- Three novel quassinoids, javanicolides A and B, and javanicoside A, from seeds of Brucea javanica
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Two novel quassinoids, javanicolides A and B, and one novel quassinoid glucoside, javanicoside A were isolated from the seeds of Brucea javanica Merr. (Simaroubaceae), along with four known quassinoids, yadanziolides A and D, and bruceins D and E, and two known quassinoid glucosides, yadanziosides D and L. Their structures were elucidated by the analysis of spectral data and chemical evidence.
- Kim, Ik Hwi,Suzuki, Ryoko,Hitotsuyanagi, Yukio,Takeya, Koichi
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- A new megastigmane glucoside and three new flavonoid glycosides from spiraea prunifolia var. simpliciflora
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A new megastigmane glucoside, simplicifloranoside (1), and three new flavonol glycosides, prunifolianosides A-C (2-4, resp.), were isolated from the aerial parts of Spiraea prunifolia var. simpliciflora. In addition, fifteen known compounds, including five phenolic acids, three lignans, four flavonoids, one eugenol glycoside, and two alkyl-primeverosides, were also identified. Their structures were elucidated on the basis of detailed spectroscopic analyses and acid hydrolysis. Copyright
- Yean, Min Hye,Kim, Ju Sun,Kang, Sam Sik,Kim, Yeong Shik
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- Two new bufadienolides and one new pregnane from Helleborus thibetanus
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Two new bufadienolides, 3β,14β,16β-trihydroxy-5α-bufa-20,22-dienolide (1) and 14β-hydroxy-3β-[β-D-glucopyranosyl-(1→6)-(β-D-glucopyranosyl)oxy]-5α-bufa-20,22-dienolide (2), one new pregnane, 3β-hydroxypregna-5,16-diene-20-one-1β-yl sulfate (3), along with
- Zhang, Hui,Su, Yanfang,Yang, Fengying,Zhao, Zeqing,Gao, Xiumei
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- Flavonoids from Malus hupehensis and their cardioprotective effects against doxorubicin-induced toxicity in H9c2 cells
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Three biflavonoid glycosides along with 12 known flavonoids, were isolated from leaves of Malus hupehensis. The complete structures of two of the compounds were established from analysis of MS, NMR spectroscopic and CD data, as well as DFT CD calculations they were determined to be atropisomeric along a central biaryl axis. The antioxidant activities and protective effects of the compounds against doxorubicin-induced cardiomyopathy in H9c2 cells were also investigated. Amongst all of the isolated compounds, quercetin was the most active radical scavenger with EC50 values of 3.2 μM and 17.8 μM by the DPPH and ABTS+ methods, respectively. The results indicated that three of the flavanoids also had a strong protective influence against doxorubicin-induced cell death with EC50 values of 8.3, 5.2 and 7.6 μM, respectively.
- Wang, Shu-Qi,Zhu, Xiao-Feng,Wang, Xiao-Ning,Shen, Tao,Xiang, Feng,Lou, Hong-Xiang
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- Alkenes with antioxidative activities from Murraya koenigii (L.) Spreng
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Four new alkenes (1-4), and six known alkenes (5-12) were isolated from Murraya koenigii (L.) Spreng. Their structures were elucidated on the basis of spectroscopic analyses and references. Compounds (1-12) were evaluated for antioxidative activities. Amo
- Ma, Qin-Ge,Xu, Kun,Sang, Zhi-Pei,Wei, Rong-Rui,Liu, Wen-Min,Su, Ya-Lun,Yang, Jian-Bo,Wang, Ai-Guo,Ji, Teng-Fei,Li, Lu-Jun
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- Eremophilane derivatives from Senecio dianthus
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From the aerial parts of Senecio dianthus, five eremophilane glucosides (1, 2, 4-6) and one new eremophilenolide (7) were isolated, together with sixteen known compounds (3, 8-22). Their structures and relative configurations were elucidated on the basis of extensive spectroscopic analysis, including HR-ESI-MS, X-ray, CD, 1D- and 2D-NMR experiments.
- Huang, Shuai,Zhou, Xian-Li,Wang, Hong-Yan,Wang, Cui-Juan,Zhou, Xiao-Li,Xiao, Feng,Weng, Jie
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- Monoterpene derivatives with anti-allergic activity from red peony root, the root of Paeonia lactiflora
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The methanolic extract and its subfractions from red peony root, the dried roots of Paeonia lactiflora Pallas showed potent antiallergic effects, as inhibition of immunoglobulin E (IgE)-mediated degranulation in rat basophil leukemia (RBL)-2H3 cells. Bioassay-guided fractionation led to the isolation of 16 monoterpene derivatives, including 3 new compounds, paeoniflorol (1), 4′-hydroxypaeoniflorigenone (2) and 4-epi-albiflorin (3), together with 13 known ones (4-16). The chemical structures of the new compounds were elucidated on the basis of spectroscopic and chemical evidences. Among the isolated monoterpene derivatives, nine compounds showed potent anti-allergic effects and compound 1 was the most effective. A primary structure-activity relationship of monoterpene derivatives was discussed.
- Shi, Yan-Hong,Zhu, Shu,Ge, Yue-Wei,He, Yu-Min,Kazuma, Kohei,Wang, Zhengtao,Yoshimatsu, Kayo,Komatsu, Katsuko
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- Cytisine-type alkaloids and flavonoids from the rhizomes of Sophora tonkinensis
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Abstract: A new cytisine-type alkaloid, (?)-N-hexanoylcytisine (1), and a new isoflavan, (3S, 4R)-4-hydroxy-7,4′-dimethoxyisoflavan 3′-O-β-d-glucopyranoside (2), along with 10 known compounds, were isolated from the rhizomes of Sophora tonkinensis. Their structures were determined by spectroscopic methods, chemical evidence, and ECD data analysis. All of the isolates were evaluated for their cytotoxic activities against four human tumor cell lines.
- Pan, Qi-Ming,Zhang, Gui-Jie,Huang, Ri-Zhen,Pan, Ying-Ming,Wang, Heng-Shan,Liang, Dong
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- Two new glycosidal metabolites of endophytic fungus Penicillium sp. (NO.4) from Tapiscia sinensis
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Two new glycosides, 8-O-β-D-glucopyranosyl-6-methyl-1-carboxylate methyl ester xanthone (1) and 4'-O-β-d-galactopyranosyl djalonensone (2), together with four known compounds, 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylate methyl ester (3), cassionllin (4), djalonensone (5) and alternariol (6), were isolated from the endophytic fungus Penicillium sp. (NO.4) of Tapiscia sinensis Oliv. The structures of compounds 1-6 were elucidated by the analysis of 1D and 2D NMR and HRMS. The cytotoxic activities of these compounds were evaluated against four cancer cell lines, as well as antimicrobial activities against two plant-pathogenic microbes. Compounds 1-6 showed moderate cytotoxicity against the A549 cancer cell line with IC50values ranging from 6.8 to 35.8 μg mL-1and were found to be inactive against three other cancer cell lines MCF-7, Caski and Hep G-2.
- Wan, Qiao,Feng, Ziwei,Li, Xueshuang,Lv, Mengmeng,Guo, Zhiyong,Deng, Zhangshuang,Zou, Kun
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- Furofuran Lignan Glucosides with Estrogen-Inhibitory Properties from the Bangladeshi Medicinal Plant Terminalia citrina
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Extracts from the leaves of the Bangladeshi medicinal plant Terminalia citrina were prepared, and 13 new furofuran lignan glucosides, terminalosides A-K (1-4, 6-12), 2-epiterminaloside D (5), and 6-epiterminaloside K (13), were characterized using various spectroscopic techniques. Twelve of the isolates were found to contain rare tetraoxygenated aryl groups in their structures. Analysis of the NMR chemical shifts for the oxymethine signals in the furofuran ring suggested a pragmatic approach to determining the relative configuration of these compounds. The ECD and NOESY spectroscopic data obtained allowed for the deduction of the absolute configurations and conformations of the compounds. The isolates were tested for their estrogenic/antiestrogenic activity using the MCF-7 and T47D estrogen-responsive human breast cancer cell lines. Terminalosides B (2) and G (8) exhibited inhibitory effects for both cell lines, and estradiol-enhanced cell proliferation was suppressed by 90% at concentrations lower than 10 M. Terminaloside E (6) showed inhibitory activity against the T47D cell line, whereas terminalosides C (3), F (7), and I (10) and 6-epiterminaloside K (13) displayed antiestrogenic activity against MCF-7 cells.
- Muhit, Md. Abdul,Umehara, Kaoru,Mori-Yasumoto, Kanami,Noguchi, Hiroshi
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- Flavone tetraglycosides and benzyl alcohol glycosides from the Mongolian Medicinal plant dracocephalum ruyschiana
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From an extract of the aerial parts of Dracocephalum ruyschiana, five new flavone tetraglycosides, five new benzyl alcohol glycosides, and 19 known compounds were isolated. The tetraglycosides contain a 7-O-β-D- glucopyranosyl-(1→2)-β-D-glucopyranosyl-( 1→2)-[α-L- rhamnopyranosyl-(1→6)]-β-D-glucopyranosyl moiety. The benzyl alcohol glycosides had acyl groups on their glycosyl or aglycone moieties. The compounds were tested for antioxidant activity using DPPH. Although the new compounds were not active, phenylpropanoylquinic acid derivatives were revealed as radical scavengers in D. ruyschiana.
- Selenge, Erdenechimeg,Murata, Toshihiro,Kobayashi, Kyoko,Batkhuu, Javzan,Fumihiko Yoshizaki
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- A C14-polyacetylenic glucoside with an α-pyrone moiety and four C10-polyacetylenic glucosides from Mediasia macrophylla
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Polyacetylenic glucosides (1-5) were isolated from the MeOH extract of Mediasia macrophylla, and their structures were established by spectroscopic analyses. Compounds 2-4 were the first examples of C10-polyacetylenic glucosides found in the family Umbelliferae, while compound 1 was a unique polyacetylenic glucoside possessing an α-pyrone moiety.
- Kurimoto, Shin-ichiro,Okasaka, Mamoru,Kashiwada, Yoshiki,Kodzhimatov, Olimjon K.,Takaishi, Yoshihisa
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- Chemical constituents of the roots of Codonopsis lanceolata
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A new phenylpropanoid (1), a new alkaloid (11), and a new natural polyacetylene (17), together with nine phenolic compounds (2–10), five alkaloids (12–16), three polyacetylenes (18–20), three triterpenoidal saponins (21–23), one phenylethanoid glycoside (24), and three hexyl glycosides (25–27) with previous known structures, were isolated from the roots of Codonopsis lanceolata. All of the isolates 1–27 were evaluated for their inhibitory effects on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages and cell viability in A2780 human ovarian cancer cells. Among the isolates, lancemasides A and B have a significant inhibitory effect on the production of NO in RAW264.7 cells (IC50 values A exhibited the most potent inhibitory effect on cell viability. This is the first report on the pharmacological activities of lancemaside B (22).
- Du, Young Eun,Lee, Jin Su,Kim, Hye Mi,Ahn, Ji-Hye,Jung, In Ho,Ryu, Jong Hoon,Choi, Jung-Hye,Jang, Dae Sik
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- Rapulasides A and B: Two novel intermolecular rearranged biiridoid glucosides from the roots of Heracleum rapula
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Two novel intermolecular rearranged biiridoid glucosides, rapulasides A and B (1 and 2), have been isolated from the roots of Heracleum rapula. Their structures were identified by extensive spectral analysis especially different NMR techniques. NOESY experiment, with the help of Dreiding molecular model, was used to elucidate their relative stereochemistry. Both compounds were tested for their inhibitory effects on rabbit platelet aggregation induced by PAF, ADP, or AA, respectively. Only trends of inhibition were observed for them.
- Xiao, Weilie,Li, Shenghong,Niu, Xuemei,Zhao, Yu,Sun, Handong
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- Phytochemical Studies on Two Australian Anigozanthos Plant Species
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Phytochemical studies of two Australian Anigozanthos (kangaroo paw) species, A. rufus and A. pulcherrimus, resulted in the identification of 13 secondary metabolites. 2-Amino-6-O-p-coumarylheptanedioic acid (3) and chalcone-5′-O-(4-O-p-coumaryl)-O-β-d-glucopyranoside (12) are reported as new compounds and are accompanied by nine flavonoids (2, 5-11, 13) and two anthocyanins (1, 4). Compounds 1 and 4 were isolated as red solids from A. rufus and are likely responsible for the coloration of the flowers. Compounds 1, 3, and 6 showed weak antimicrobial activities against Acinetobacter baumannii ATCC 19606 at concentrations of 52.4, 94.9, and 53.9 μM, respectively.
- Hendra, Rudi,Keller, Paul A.
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- Cytotoxic phenylpropanoid glycosides from Cirsium japonicum
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Three new phenylpropanoid glycosides 1–3, along with nine known phenylpropanoid glycosides 4–12, were isolated from the aerial parts of Cirsium japonicum. The structures of isolated compounds were elucidated by chemical and spectroscopic methods. Compounds 1, 3, 6, 8, and 11 showed moderate cytotoxicities against MCF-7, U87, HCT116, and A549 cell lines with IC50values in the range of 1.35–11.32?μM. The known compounds 4–12 were obtained from this plant for the first time.
- Shang, Dong-Li,Ma, Qin-Ge,Wei, Rong-Rui
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- Phytochemical investigation of the fruit peels of Citrus reticulata Blanco
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Phytochemical investigation of the fruit peels of Citrus reticulata Blanco (Rutaceae) resulted in the isolation of three new phytoconstituents along with n-hexacosonoic acid. Their structures have been established as 18H-urs-5,11-dien-3-ol-11-one-3-D-gluc
- Khan, M. Aasim,Ali,Alam, Prawez
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- Isolation, identification and bioactivities of abietane diterpenoids from: Premna szemaoensis
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Investigation of the leaves and stems of Premna szemaoensis resulted in the isolation of twelve new abietane diterpenoids, szemaoenoids A-L (1-12), together with four known abietane diterpenoids (13-16). The structures involved two rearranged-abietane skeletons: 17(15 → 16)-abeo-abietane (7, 10-12, 14 and 15) and 17(15 → 16),18(4 → 3)-diabeo-abietane (1-6, 13 and 16). The structures of the new compounds were established mainly by analyzing NMR and HRESIMS data. The absolute configurations of 1, 3 and 10 were confirmed by single crystal X-ray diffraction analysis. In bioactivity assays, compounds 11, 12, 14 and 15 were active against two human colon cancer cell lines (HCT-116 and HT-29) with IC50 values ranging from 8.8 to 34.3 μM, and compounds 10, 13 and 14 exhibited effective free radical scavenging activity with IC50 values ranging from 35.6 to 41.5 μM by DPPH experiment.
- Pu, De-Bing,Wang, Ting,Zhang, Xing-Jie,Gao, Jun-Bo,Zhang, Rui-Han,Li, Xiao-Nian,Wang, Yong-Mei,Li, Xiao-Li,Wang, He-Yao,Xiao, Wei-Lie
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- Antihepatotoxic, nephroprotective, and antioxidant activities of phenolic compounds from Satureja macrostema leaves against carbon tetrachloride-induced hepatic damage in mice
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Satureja macrostema (SM) is used with culinary and medicinal purposes. Methanol extract from SM was investigated for its phenolic content, antioxidant, hepatoprotective, and kidney protective activities. Liver and kidney damage were induced in rats with CCl4. Hepatoprotective efficacy was measured by the activity of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, cholesterol, high density lipoprotein and total protein, and lipid peroxidation. Kidney function was evaluated by measuring plasma urea and creatinine. Antioxidant activity was evaluated by measuring blood glutathione content, superoxide dismutase and catalase activities, and malondialdehyde equivalent; their activity was comparable to that of silymarin, a well-known hepatoprotective agent. Methanol extracts of S. macrostema showed potent antioxidant, kidney protective, and hepatoprotective activities; in-depth chromatographic investigation resulted in the identification of six new flavonoid glycosides: 5-hydroxy-3,6,4′- trimethoxyflavonol-7-C-α-l-rhamnopyranosyl-(1 → 3)-β-d- glucopyranoside (2), 4′-methoxy-5,7,3′,5′-tetra- hydroxyflavanone-3-O-β-d-rhamnopyranosyl-(1 → 2)-β-d- rhamnopyranoside (3), 5,4′-dimethoxy-7,3′,5′- trihydroxyflavanone-3-O-β-d-rhamnopyranoside (4), 5,3′,4′, 5′-tetrahydroxyflavanone-7-O-β-d-rhamnopyranoside (5), 5,3′,4′,5′-tetramethoxyflavanone-7-O-β-d- rhamnopyranoside (6), and 5,4′-dimethoxy-3′-hydroxyflavone-7-β- d-rhamnopyranoside (8) along with three known compounds: 5-hydroxy-7,4′- dimethoxyflavone (1), prunin (7), and diosmin (9) that were isolated. Structural elucidation of the new compounds was established based on the spectral data. The present study revealed that S. macrostema leaves have a significant radical scavenging and hepatoprotective activity.
- Gutierrez, Rosa Martha Perez
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- A novel hexanordammarane glycoside from the leaves and stems of Panax quinquefolium L.
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One novel hexanordammarane glycoside, ginsenoside R10, was isolated from the leaves and stems of Panax quinquefolium L. as a minor constituent. It is the first time that a hexanordammarane glycoside isolated from the plant of Panax quinquefolium L. Its structure was elucidated as 3-O-β-D-glucopyranosyl-3β, 12β-dihydroxy-22, 23, 24, 25, 26, 27-hexanordammarane-20-one (1), by the combination analysis of one-dimensional NMR, two-dimensional NMR and mass spectrometry.
- Liu, Jin-Ping,Lu, Dan,Li, Ping-Ya
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- Hydrolysis of cellulose in 1-allyl-3-methylimidazolium chloride catalyzed by methyltrioxorhenium
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Methyltrioxorhenium (MTO) has been applied as catalyst to promote cellulose hydrolysis by using the ionic liquid 1-allyl-3-methylimidazolium chloride ([Amim]Cl) as solvent. When using 7 mol% of MTO, 70 μL of water, ca. 0.6 mmol of microcrystalline cellulose and 2.0 g of [Amim]Cl under microwave irradiation for 30 min at 150 °C, 51.2% of total reducing sugar (TRS) and 24.7% of glucose yield can be obtained. The nucleophilic attack of electron-rich O atom of β-1,4-glycosidic bond to electron-poor Re atom of MTO, leading to the broken of β-1,4-glycosidic bond, is assumed to be crucial for cellulose degradation.
- Yuan, Yuguo,Wang, Jingyun,Fu, Nihong,Zang, Shuliang
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- Flavonoids from silkworm droppings and their promotional activities on heme oxygenase-1
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A new flavane glucoside, 7,2'-dihydroxy-8-hydroxyethyl-4'-methoxyflavane- 2'-O-β-d-glucopyranoside (3), along with three known flavonoids, 7,2'-dihydroxy-8-prenyl-4'-methoxyflavane (1), euchrenone a7 (2), and 7,2'-dihydroxy-8-prenyl-4'-methoxy-2'-O-β-d-glucopyranosylflavane (4), was isolated from silkworm droppings. The structures of the compounds were elucidated on the basis of 1D and 2D NMR spectroscopic analyses and optical rotational characteristics. The compounds isolated from silkworm droppings were evaluated for their effects on heme oxygenase-1 (HO-1) activity. Compounds 1 and 3 increased the expression of HO-1 in HepG2 cells. HO-1 is an antioxidant enzyme that catabolizes heme to carbon monoxide, free iron, and biliverdin, all of which are involved in the suppression of inflammatory mediators.
- Park, Ji-Hae,Lee, Dae-Young,Yun, Pyeong,Yeon, Seung-Woo,Ko, Jong Hee,Kim, Yong-Soon,Baek, Nam-In
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- Four new monoterpenoid glycosides from the flower buds of Magnolia biondii
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Four new monoterpenoid glycosides 1-4, named magnoliaterpenoid A-D, were isolated from a 50% aqueous acetone extract of flower buds of Magnolia biondii, along with one known compound, (1′R,3′S,5′R,8′S,2Z,4E)-dihydrophaseic acid 3-O-β-D-glucopyranoside (5). Their structures and relative configuration were identified by extensive spectroscopic analysis (IR, UV, MS, 1D and 2D NMR). The aglycones of these four new compounds possess seven-membered rings systems, which are very rare. A plausible biosynthetic route for the four new compounds was proposed via the biogenetic isoprene rule. Compounds 1, 2, 3, and 4 showed no antimicrobial activity at the concentration range of 1.95-250 μg/mL.
- Feng, Wei-Sheng,He, Yu-Huan,Zheng, Xiao-Ke,Wang, Jian-Chao,Cao, Yan-Gang,Zhang, Yan-Li,Song, Kai
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- Osteosaponins 1 and 2: Two new saponin glycosides from Osteospermum vaillantii
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Osteospermum vaillantii (Decne) T. Norl., collected from southern Saudi Arabia, yielded two new saponins characterised as 3-O-β-D-glucopyranosyl- (2′ → 1″)-β D-glucopyranosyl-(3′ → 1?)-O-β D-galactopyranosyl-oleanolic acid, designated as osteosaponin (1),
- Ahmed, Bahar,Khan, Riaz A.,Al-Howiriny, Tawfeq A.,Al-Rehaily, Adnan J.
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- Regeneration of cello-oligomers via selective depolymerization of cellulose fibers derived from printed paper wastes
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Cellulose extracted from printed paper wastes were selectively depolymerized under controlled conditions into cello-oligomers of controllable chain lengths via dissolution in an ionic liquid, 1-allyl-3-methylimidazolium chloride (AMIMCl), and in the presence of an acid catalyst, Amberlyst 15DRY. The depolymerization process was optimized against reaction temperature, concentration of acid catalyst, and reaction time. Despite rapid initial depolymerization process, the rate of cellulose depolymerization slowed down gradually upon prolonged reaction time, with 75.0 wt% yield of regenerated cello-oligomers (mean Viscosimetric Degree of Polymerization value of 81) obtained after 40 min. The depolymerization of cellulose fibers at 80 °C appeared to proceed via a second-order kinetic reaction with respect to the catalyst concentration of 0.23 mmol H3O+. As such, the cellulose depolymerization process could afford some degree of control on the degree of polymerization or chain lengths of cello-oligomers formed.
- Voon, Lee Ken,Pang, Suh Cem,Chin, Suk Fun
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- Isolation and evaluation of kaempferol glycosides from the fern Neocheiropteris palmatopedata
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Kaempferol glycosides, named palmatosides A (1), B (2) and C (3), together with three known kaempferol glycosides, multiflorins A (4) and B (5), and afzelin (6), were isolated from the roots of the fern Neocheiropteris palmatopedata. Palmatosides A (1) and B (2) each possessed an unusual sugar moiety containing a 4,4-dimethyl-3-oxo-butoxy substituent group. The isolated compounds were evaluated for their cancer chemopreventive potential based on their ability to inhibit tumor necrosis factor alpha (TNF-α)-induced NF-κB activity, nitric oxide (NO) production, aromatase, quinone reductase 2 (QR2) and COX-1/-2 activities. Palmatosides B (2) and C (3) inhibited TNF-α-induced NF-κB activity with IC50 values of 15.7 and 24.1 μM, respectively; multiflorin A (4) inhibited aromatase enzyme with an IC50 value of 15.5 μM; afzelin (6) showed 68.3% inhibition against QR2 at a concentration of 11.5 μg/ml; palmatoside A (1) showed 52% inhibition against COX-1 enzyme at a concentration of 10 μg/ml; and multiflorin B (5) showed 52% inhibition against nitric oxide production at a concentration of 20 μg/ml. In addition, compounds 3-6 were shown to bind QR2 enzyme using LC-MS ultrafiltration binding assay.
- Yang, Jian-Hong,Kondratyuk, Tamara P.,Marler, Laura E.,Qiu, Xi,Choi, Yongsoo,Cao, Hongmei,Yu, Rui,Sturdy, Megan,Pegan, Scott,Liu, Ying,Wang, Li-Qin,Mesecar, Andrew D.,Breemen, Richard B. Van,Pezzuto, John M.,Fong, Harry H.S.,Chen, Ye-Gao,Zhang, Hong-Jie
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- Platinum-Catalyzed aqueous-Phase hydrogenation of d?Glucose to d?Sorbitol
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Aqueous-phase hydrogenation of D-glucose to D-sorbitol was systematically investigated over silica-supported Pt nanoparticles to elucidate structure?reactivity relations and mechanistic insight. D-Glucose hydrogenation over large Pt particles competes with its isomerization to D-fructose over low-coordination (electron-deficient) Pt sites; D-sorbitol production by the former process was structure insensitive for nanoparticles spanning 3?17 nm, whereas isomerization was favored by smaller particles, with both pathways independent of the choice of fumed silica or mesoporous SBA-15 support. While D-fructose was readily hydrogenated to D-mannitol under the same reaction conditions, the latter underwent minimal isomerization to D-sorbitol, which is, therefore, a direct product of D-glucose ring opening and subsequent hydrogenation of the aldose conformer. D-Sorbitol production was favored by low D-glucose concentrations (2 pressures (>40 bar), and low reaction temperatures (140 °C), which suppressed undesired polymerization side reactions.
- Zhang, Xingguang,Durndell, Lee J.,Isaacs, Mark A.,Parlett, Christopher M.A.,Lee, Adam F.,Wilson, Karen
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- Microchip Device for Performing Enzyme Assays
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An automated enzyme assay was performed within a microfabricated channel network. Precise concentrations of substrate, enzyme, and inhibitor were mixed in nanoliter volumes using electrokinetic flow. Reagent dilution and mixing were controlled by regulating the applied potential at me terminus of each channel, using voltages derived from an equivalent circuit model of the microchip. The enzyme β-galactosidase (β-Gal) was assayed using resorufin β-D-galactopyranoside (RBG), a substrate that is hydrolyzed to resorufin, a fluorescent product Reaction kinetics were obtained by varying the concentration of substrate on-chip and monitoring the production of resorufin using laser-induced fluorescence. Derived Michaelis-Menten constants compared well between an on-chip and a conventional enzyme assay. Bias in the derived Km and kcat was primarily due to the limited solubility of RBG and the associated lack of measurements at substrate concentrations exceeding the Km. A Ki of 8 μM for the inhibitor phenylethyl β-D-thiogalactoside (PETG) was determined from plots of initial rate versus substrate concentration obtained at three concentrations of PETG. The relative inhibition of β-Gal by lactose, p-hydroxymercuribenzoic acid, and PETG was determined by varying the inhibitor concentration with constant enzyme and substrate concentration. An enzyme assay performed on the microchip within a 20-min period required only 120 pg of enzyme and 7.5 ng of substrate, reducing the amount of reagent consumed by 4 orders of magnitude over a conventional assay.
- Hadd, Andrew G.,Raymond, Daniel E.,Halliwell, John W.,Jacobson, Stephen C.,Ramsey, J. Michael
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- A new steroidal saponin from Allium ampeloprasum var. porrum with antiinflammatory and gastroprotective effects
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A new steroidal saponin was isolated from the bulbs of Allium ampeloprasum var. porrum. On the basis of chemical conversions and detailed analyses of 1H and 13C NMR spectra including 2D NMR spectroscopic techniques, its structure was established as 3-[(O-β-d-glucopyranosyl-(1 → 3)-β-d-glucopyranosyl-(1 → 2)-O-[O-β-d-glucopyranosyl-(1 → 3)]-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranosyl)oxy] -2,6-dihydroxy-(2α,3β,5α,6β,25R)-spirostane. Results of the present study indicated that the steroidal saponin showed haemolytic effects in the in vitro assays and demonstrated antiinflammatory activity and gastroprotective property using in vivo models.
- Adao, Camila Rodrigues,Da Silva, Bernadete Pereira,Parente, Jose Paz
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- New monoterpenoids from the stigmas of Crocus sativus
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One new compound, crocusatin M (1), and three new glycosidic compounds, crocusatins N-P (2–4), along with nine known compounds were isolated from the dried stigmas of Crocus sativus. The structures of new compounds were elucidated on the basis of spectros
- Fang, Qing-Wei,Fu, Wen-Wei,Yang, Jin-Ling,Lu, Yue,Chen, Jiang-Cheng,Wu, Pei-Ying,Zhang, Xue,Xu, Hong-Xi
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- The main factors affecting the catalytic properties of Ru/Cs-HPA systems in one-pot hydrolysis-hydrogenation of cellulose to sorbitol
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One-pot conversion of mechanically activated cellulose to sorbitol was investigated over bifunctional catalysts based on Ru (0.6, 1 and 3 wt.%) and cesium salts of heteropoly acids (HPA) Cs2.1H0.9PW12O40 and Cs3HSiW12O40 (Cs-PW and Cs-SiW, respectively). The maximal yield of sorbitol equal to 59 % and selectivity 94 % were achieved over the 1%Ru/Cs3HSiW12O40 catalyst. Physicochemical and catalytic data showed that the rate-determining step, i.e. the hydrolysis of cellulose, depended on the surface acidity of catalysts, whereas Ru content in catalyst affected both the hydrolysis and the hydrogenation steps. The kinetic parameters for one-pot conversion of cellulose were determined by mathematical modeling approach and were successfully used for the prediction of the yields of sorbitol and mannitol.
- Gerasimov, Evgeniy Yu.,Gromov, Nikolay V.,Kozhevnikov, Ivan V.,Medvedeva, Tatiana B.,Panchenko, Valentina N.,Parmon, Valentin N.,Said-Aizpuru, Olivier,Taran, Oxana P.,Timofeeva, Maria N.
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- Two New Triterpenoid Glycosides from the Roots of Rosa cymosa Tratt.
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Two new triterpenoid glycosides, 3α,19α,23α-trihydroxy-2-oxo-12-ursen-28-O-β-d-glucopyranoside (1) and 3α,19α,23α-trihydroxy-2-oxoolean-12-en-28-O-β-d-glucopyranoside (2) as well as three known compounds, 2α,3α,19α-trihydroxyolean-12-en-28-O-β-d-glucopyranoside (3), 2α,3α,19α,23-tetrahydroxy-12-ursen-28-O-β-d-glucopyranoside (4), and 2α,3β,19α,23-tetrahydroxyurs-12-en-28-oic acid (5) were isolated from 75% EtOH extract of Rosa cymosa. Their structures were elucidated by extensive spectroscopic methods. All the isolated compounds displayed moderate inhibitory activity against LPS-induced NO production in macrophages.
- Ma, Guo-Xu,Huang, Xiao-Yan,Dai, Hua-Nian,Zhong, Xiao-Qing,Zhou, Yan-Lin,Su, Zuo-Lin,He, Ying-Zi,Yang, Jun-Shan,Yuan, Jing-Quan,Xu, Xu-Dong
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- A new diterpenoid glucoside and two new diterpenoids from the fruit of Vitex agnus-castus
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A new labdane-type diterpenoid glucoside and two new labdane-type diterpenoids were isolated from the fruit (chasteberry) of Vitex agnus-castus L. (Verbenaceae) along with 14 known compounds comprising seven labdane-type diterpenoids, one halimane-type diterpenoid, two oleanane-type triterpenoids, two ursane-type triterpenoids, one aromadendrane-type sesquiterpenoid, and one flavonoid. Their structures were characterized on the basis of spectroscopic data as well as chemical evidence. Furthermore, the antioxidative activities of the flavonoid were evaluated using five different analyses.
- Ono, Masateru,Eguchi, Keisuke,Konoshita, Masatarou,Furusawa, Chisato,Sakamoto, Junich,Yasuda, Shin,Ikeda, Tsuyoshi,Okawa, Masafumi,Kinjo, Junei,Yoshimitsu, Hitoshi,Nohara, Toshihiro
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- Anti-inflammatory constituents from Psychotria prainii H. Lév
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One new and three known compounds were isolated from the ethanol extract of Psychotria prainii aerial parts. By means of spectroscopic methods, their structures were elucidated to be deacetylasperulosidic acid 6-ethyl ether (1), asperulosidic acid (2), asperuloside (3) and obtucarbamates C (4). The isolated compounds were evaluated for their inhibitory effect on NO production in LPS-stimulated RAW264.7 cells. Among them, compounds 2 and 4 exhibited strong effect with the IC50 values of 5.75?±?0.85 and 6.92?±?0.43?μM, respectively. This is the first report for the chemical composition and biological activity of P. prainii.
- Tran, Phi Hung,Le, Viet Dung,Do, Thi Ha,Nguyen, Thi Luyen,Nguyen, Phuong Thao,Nguyen, Trong Thong,Nguyen, Tien Dat
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- Effective conversion of cellobiose and glucose to sorbitol using non-noble bimetallic NiCo/HZSM-5 catalyst
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The tandem hydrolysis and hydrogenation of saccharides into sorbitol is an especially attractive reaction in the conversion of biomass. Here, an economical and efficient bimetallic catalyst for the transformation of glucose and cellobiose into sorbitol is reported. Non-precious metal based catalysts such as NiCo, Ni, and Co, were prepared via modified impregnation method, and NiCo/HZSM-5 showed superior performance for the synthesis of sorbitol (86.9% from cellobiose, 98.6% from D-glucose). Various characterizations, such as Brunner-Emmet-Teler (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), confirmed that NiCo alloy formed and highly dispersed in NiCo/HZSM-5 catalyst. The high performance of fabricated catalyst would be attributed to the formation of nickel-cobalt alloy over HZSM-5 zeolite surface. High temperature and H2 pressure were favorable for the tandem hydrolysis and hydrogenation reaction. Besides, the reaction pathway was also proposed based on the kinetics study. Cellobitol was detected as the intermediate in the reaction mixture. Furthermore, in the catalytic stability study, it was found that active metal species of NiCo/HZSM-5 were stable. The deactivation of catalyst would be due to the covering of acidic sites over NiCo/HZSM-5.
- Zada, Bakht,Yan, Long,Fu, Yao
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- Antibacterial and cytotoxic phenolic metabolites from the fruits of amorpha fruticosa
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Fourteen new natural products, namely, 2-[(Z)- styryl]-5-geranylresorcin-1-carboxylic acid (1), amorfrutin D (2), 4-O-demethylamorfrutin D (3), 8-geranyl-3,5,7- trihydroxyflavanone (4), 8-geranyl-5,7,3′-trihydroxy-4′-methoxyisoflavone (5), 6-geranyl-5,7,3
- Muharini, Rini,Diaz, Adriana,Ebrahim, Weaam,Mándi, Attila,Kurtán, Tibor,Rehberg, Nidja,Kalscheuer, Rainer,Hartmann, Rudolf,Orfali, Raha S.,Lin, Wenhan,Liu, Zhen,Proksch, Peter
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- Four new triterpenoids from callicarpa kwangtungensis
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Four new triterpenoids which were identifed as 2α,3β,6β,19α-Tetrahydroxyoleanolic acid 28-O-β-D-glucopyranoside (1), 2-O-β-D-glucopyranosyloxy-3α,19α-dihydroxyoleanolic acid (2), 2-O-β-D-glucopyranosyloxy-3α,19α-dihydroxyursolic acid (3), 2α,3α,6β,19α-Tetrahydroxyursolic acid 28-O-β-D-glucopyranoside (4), were isolated from the aerial parts of Callicarpa kwangtungensis together with three known triterpenoids identified as 2α,3β,21β-Trihydroxyursolic acid 28-O-β-D-glucopyranoside (5), 2α,3α,19α,23-tetrahydroxyoleanolic acid 28-O-β-D-glucopyranoside (6), 2α,3α,19α,23-Tetrahydroxyursolic acid 28-O-β-D-glucopyranoside (7). Their structures were elucidated by the combination of mass spectrometry (MS), one and two-dimensional NMR experiments.
- Zhou, Guo-Ping,Yu, Yan,Yuan, Ming-Ming,Ji, Tengfei,Fu, Hui-Zheng,Zhong, Rui-Jian
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- Steric course of the hydrolysis of alpha,alpha-trehalose and alpha-D-glucosyl fluoride catalyzed by pig kidney trehalase.
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We are unable to confirm the report of Labat et al.3 that pig kidney trehalase hydrolyzes alpha,alpha-trehalose to form solely alpha-D-glucose. Highly purified trehalase from pig renal cortex was found, in reactions monitored by 1H-n.m.r. spectra, to hydrolyze alpha,alpha-trehalose with the formation of both alpha- and beta-D-glucose. That the beta anomer constitutes the enzymically mobilized glucosyl residue is indicated by the further finding that beta-D-glucose is the product formed on hydrolysis of alpha-D-glucosyl fluoride by the enzyme. Present results show the stereochemical behavior of pig kidney trehalase in hydrolyzing alpha,alpha-trehalose to be indistinguishable from that reported by ourselves and others for trehalase preparations from a range of biological sources including rabbit renal cortex.
- Nakano,Brewer,Kasumi,Hehre
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- A new dihydrochalcone glycoside from the stems of Homalium stenophyllum
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A new dihydrochalcone glycoside, phloretin-4-O-β-D-glucopyranoside (1), together with seven known flavonoids (2–8), were isolated from the stems of Homalium stenophyllum. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. The known compounds (2–8) were isolated from the genus Homalium for the first time. All compounds were evaluated for their antibacterial activities against six pathogenic bacteria in vitro.
- Wu, Shou-Yuan,Fu, Yan-Hui,Zhou, Qi,Bai, Meng,Chen, Guang-Ying,Han, Chang-Ri,Song, Xiao-Ping
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- A new alkylene dihydrofuran glycoside with antioxidation activity from the root bark of Morus alba L
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A new alkylene dihydrofuran glycoside (1) was isolated from the root bark of Morus alba L., along with moracin M-3′-O-β-Dglucopyranoside (2), and moracin M-6, 3′-di-O-β-D-glucopyranoside (3). Compound 1 was identified as 2-methylene-3-methoxy-2, 5-dihydrofuran-4-O-β-D- glucopyranoside on the basis of chemical and spectroscopic data including 1D and 2D NMR spectral analysis. In addition, the antioxidant activity of 1 was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The IC50 values were 2.49 and 0.45 mg/mL, respectively.
- Fu, Wei,Lei, Yong Fang,Cai, Ya Ling,Zhou, Dao Nian,Ruan, Jin Lan
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- Three new phthalides from gnaphalium adnatum
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Three new phthalides, gnaphalides A-C (1 - 3, resp.), together with three known phthalides, were isolated from the aerial part of Gnaphalium adnatum. The structures of the new compounds were elucidated as 6-(1,1-dimethylprop-2-en-1-yl)-5,7-dihydroxy-2-benzofuran-1(3H)-one (1), 5-hydroxy-7- [(2-hydroxy-3-methylbut-3-en-1-yl)oxy]-2-benzofuran-1(3H)-one (2), and 1,3-dihydro-7-[(3-methylbut- 2-en-1-yl)oxy]-1-oxo-2-benzofuran-5-yl β-d-glucopyranoside (3) on the basis of spectral analyses. The structure of 1 was also confirmed by X-ray crystallographic analysis. The three known phthalides, identified as 5,7-dihydroxyisobenzofuran-1(3H)-one (4), anaphatol (5), and 7-O-(β-glucopyranosyl)-5- hydroxyisobenzofuran-1(3H)-one (6), were isolated from the genus Gnaphalium for the first time.
- Zheng, Xing-Ping,Cui, Qiong-Fang,Zhao, Jing-Feng,Yang, Li-Juan,Zhang, Hong-Bin,Yang, Xiao-Dong,Li, Liang
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- IMMOBILIZED ENZYME KINETIC STUDY OF D-GLUCOSE MUTAROTATION BY FLOW INJECTION ANALYSIS.
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A novel analytical application of immobilized enzymes is presented in which the mutarotation kinetics of D-glucose are studied. A glucose oxidase single bead string reactor is combined with the Trinder reaction in a flow injection system. The apparatus is used to monitor the mutarotation of D-glucose in a batch reactor. The mutarotation coefficients obtained are in good agreement with the literature values. Phosphate ion is shown to catalyze the reaction and the mutarotation coefficient is directly proportional to its concentration. The selectivity of the enzyme reactor is also demonstrated.
- Stults,Wade,Crouch
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- An anti-inflammatory C-stiryl iridoid from Camptosorus sibiricus Rupr.
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A new iridoid glycoside, named camptoside (1), together with three known compounds as dehydrodiconiferyl alcohol-9′-O-β-D-glucopyranoside (2), aesculetin (3) and vajicoside (4), have been isolated from Camptosorus sibiricus Rupr. (Aspleniaceae). Their structures were established on the basis of spectroscopic analysis, especially 1D- and 2D-NMR data, and by comparison of their spectroscopic and physical data with those reported in the literature. Compounds 1–3 exhibited inhibitions of nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages with IC50 values of 11.2, 8.3 and 9.4 μM, respectively.
- Wang, Fang,Jia, Qing-Wen,Yuan, Zhen-Hai,Lv, Ling-Yue,Li, Min,Jiang, Zhi-Bo,Liang, Da-Lian,Zhang, Dai-Zhou
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- A new 2-(2-phenylethyl)chromone glycoside in Chinese agarwood “Qi-Nan” from Aquilaria sinensis
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A new 2-(2-phenylethyl)chromone glycoside, 2-[2-(4-glucosyloxy-3-methoxyphenyl)ethyl]chromone (1), was isolated from the high-quality Chinese agarwood “Qi-Nan” originating from Aquilaria sinensis (Lour.) Glig. The structure including the absolute configuration of the sugar moiety was elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR), MS analysis, PMP-labeling HPLC analysis methods, as well as comparison with literature data. To the best of our knowledge, it is the first time that chromone glycoside was discovered in agarwood, or even in the whole Aquilaria plants.
- Shao, Hang,Mei, Wen-Li,Kong, Fan-Dong,Dong, Wen-Hua,Li, Wei,Zhu, Guo-Peng,Dai, Hao-Fu
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- Microtropiosides A-F: ent-Labdane diterpenoid glucosides from the leaves of Microtropis japonica (Celastraceae)
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From a 1-BuOH-soluble fraction of a MeOH extract of the leaves of Microtropis japonica, collected in the Okinawa islands, six ent-labdane glucosides, named microtropiosides A-F, were isolated together with one known acyclic sesquiterpene glucoside. Their structures were elucidated by a combination of spectroscopic analyses, and their absolute configurations determined by application of the β-d-glucopyranosylation-induced shift-trend rule in 13C NMR spectroscopy and the modified Mosher's method.
- Koyama, Yuka,Matsunami, Katsuyoshi,Otsuka, Hideaki,Shinzato, Takakazu,Takeda, Yoshio
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- Chemical constituents from the fruit of Gardenia jasminoides and their inhibitory effects on nitric oxide production
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Three new iridoid glycosides, 6″-O-trans-caffeoylgenipin gentiobioside (1), genipin 1-O-β-d-apiofuranosyl (1→6)-β-d- glucopyranoside (2), genipin 1-O-α-d-xylopyranosyl (1→6)-β-d- glucopyranoside (3), three new monocyclic monoterpenoids, jasminoside R (4),
- Peng, Kaifeng,Yang, Liguo,Zhao, Shizhe,Chen, Lixia,Zhao, Feng,Qiu, Feng
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- Three new iridoid glycosides from the fruit of gardenia jasminoides var. radicans
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Three new iridoid glycosides, 6″-O-trans-feruloylgenipin gentiobioside (1), 2'-O-trans-p-coumaroylgardoside (2), 2'-O-trans- feruloylgardoside (3), were isolated from the fruit of Gardenia jasminoides var. radicans MAKINO (Rubiaceae). The structures of th
- Qin, Fang-Min,Meng, Ling-Jie,Zou, Hui-Liang,Zhou, Guang-Xiong
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- A new cerebroside from the entomopathogenic fungus Ophiocordyceps longiissima: Structural-electronic and antioxidant relations. Experimental and DFT calculated studies
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The chemical characterization of n-butanol soluble extract of the fungus Ophiocordyceps longiissima NBRC 106965 afforded a new cerebroside, 1-O-(β-d-glucopyranosyl)-(2S,3R,4E,8E)-2-[(2′R)-2′-hydroxyheptadecanoylamino]-9-methylheptadeca-4,8-diene-1,3-diol, trivially named ophiocordylongiiside A (1), in addition to 22E,24R-24-methylcholest-5,22-diene-3-O-β-D-O-glucopyranoside (2). The chemical structure of 1 was established based upon the by modern spectroscopic and chemical techniques. Compound 1 exhibited strong DPPH-free radical scavenging with the IC50 value of 55.72 mg/mL. The biological result can be explained by density functional theoretical (DFT) calculation, in which antioxidant activity is mostly controlled by the O–H bond dissociation enthalpy (BDE) following hydrogen atom transfer (HAT) mechanism. In all studied environments, the lowest BDE values are found in 2′-OH.
- Elshamy, Abdelsamed I.,Yoneyama, Tatsuro,Trang, Nguyen Van,Son, Ninh The,Okamoto, Yasuko,Ban, Sayaka,Noji, Masaaki,Umeyama, Akemi
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- Diterpenoids with immunosuppressive activities from cinnamomum cassia
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Three new diterpenoids with unprecedented carbon skeletons, cinncassiols F (1) and G (2) and 16-O-β-d-glucopyranosyl-19-deoxycinncassiol G (3), a new isoryanodane diterpenoid, 18-hydroxyperseanol (4), six known isoryanodane diterpenoids, 5-10, and a known ryanodane diterpenoid, 11, were isolated from the stem bark of Cinnamomum cassia. Compound 1 possesses an 11,13:12,13-diepoxy- 6,11-epoxy:12,13-disecoisoryanodane diterpenoid skeleton bearing ketal and hemiketal functionalities, whereas compounds 2 and 3 feature an 11,12-secoisoryanodane diterpenoid skeleton with an 11,6-lactone moiety. The structures of the four new diterpenoids, 1-4, and their absolute configurations were established using HRESIMS, NMR, ECD, single-crystal X-ray diffraction, and chemical methods. Compounds 2 and 11 significantly inhibited the proliferation of murine T cells induced by ConA.
- Zeng, Junfen,Xue, Yongbo,Shu, Penghua,Qian, Huiqin,Sa, Rongjian,Xiang, Ming,Li, Xiao-Nian,Luo, Zengwei,Yao, Guangmin,Zhang, Yonghui
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- Exopolysaccharide Produced by Probiotic Bacillus albus DM-15 Isolated From Ayurvedic Fermented Dasamoolarishta: Characterization, Antioxidant, and Anticancer Activities
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An exopolysaccharide (EPS) was purified from the probiotic bacterium Bacillus albus DM-15, isolated from the Indian Ayurvedic traditional medicine Dasamoolarishta. Gas chromatography-mass spectrophotometry and nuclear magnetic resonance (NMR) analyses revealed the heteropolymeric nature of the purified EPS with monosaccharide units of glucose, galactose, xylose, and rhamnose. Size-exclusion chromatography had shown the molecular weight of the purified EPS as around 240 kDa. X-ray powder diffraction analysis confirmed the non-crystalline amorphous nature of the EPS. Furthermore, the purified EPS showed the maximum flocculation activity (72.80%) with kaolin clay and emulsification activity (67.04%) with xylene. In addition, the EPS exhibits significant antioxidant activities on DPPH (58.17 ± 0.054%), ABTS (70.47 ± 0.854%) and nitric oxide (58.92 ± 0.744%) radicals in a concentration-dependent way. Moreover, the EPS showed promising cytotoxic activity (20 ± 0.97 μg mL–1) against the lung carcinoma cells (A549), and subsequent cellular staining revealed apoptotic necrotic characters in damaged A549 cells. The EPS purified from the probiotic strain B. albus DM-15 can be further studied and exploited as a potential carbohydrate polymer in food, cosmetic, pharmaceutical, and biomedical applications.
- Kalimuthu, Palanisamy,Ma, Yongkun,Mathivanan, Krishnamurthy,Rai, Amit Kumar,Saravanan, Kandasamy,Sathiyanarayanan, Ganesan,Sekar, Soundarapandian,Sudharsan, Kumaresan,Vinothkanna, Annadurai
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- Three new steroidal saponins from the roots and rhizomes of Rohdea chinensis (Baker) N.Tanaka (synonym Tupistra chinensis Baker)
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Three new steroidal saponins (1–3), together with four known compounds (4–7), were isolated from the roots and rhizomes of Rohdea chinensis Baker, and their structures were determined as (24S, 25 R)-1β-hydroxy-3β-[(β-D-glucopyranoside)oxy]-spirost-5-en-24-yl-β-D-glucopyranoside (1) and (24S)-spirost-25(27)-en-1β, 3β, 4β, 5β, 6β, 24β-hexahydroxy-24-O-β-D-glucopyranoside (2), (22S, 25S)-1β, 3β, 4β, 5β, 26, 27-hexanol-furospirost-5, 26-O-β-D-glucopyranoside (3), together with four known compounds 3-epi-diosgenin-3-β-D-glucopyranosid (4), 3-epiruscogenin (5), 25(R)-1β-hydroxy-spirost-5-en-3α-yl-O-β-D-glucopyranoside (6) and tupichinin A (7), on the basis of physico-chemical properties and spectral analysis. In this study, compounds 1–3 and 5–7 were evaluated for their cytotoxic activity against SW620, A549 and HepG2 tumor cell lines. Among them, compound 7 showed moderate cytotoxicity against two human cancer cell lines A549 and HepG 2 with IC50 values of 25.3 ± 2.6 and 26.1 ± 2.5 μM, respectively.
- Song, Bei,Huang, Wenli,Li, Yuze,Zhang, Yangyang,Zhang, Huawei,Jiang, Yi,Deng, Chong,Song, Xiaomei,Liu, Jianli
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p. 108 - 115
(2019/06/10)
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- The identification of phenylpropanoids isolated from the root bark of Ailanthus altissima (Mill.) Swingle
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Chemical investigation of 75% EtOH exact of the root bark of Ailanthus altissima (Mill.) Swingle led to the isolation and identification of two new phenylpropanoids (1–2), along with six known compounds (3–8). Their chemical structures were elucidated by extensive spectroscopic data analyses including NMR experiments and HRESIMS analyses, as well as computer-assisted structure elucidation software (ACD/Spectrus Processor). All compounds were evaluated for cytotoxic activities against Hep 3B and Hep G2 cells. Compound 1 and 7 displayed weak cytotoxic activities against the Hep 3B cell line.
- Du, Ye-Qing,Yan, Zhi-Yang,Chen, Jing-Jie,Wang, Xiao-Bo,Huang, Xiao-Xiao,Song, Shao-Jiang
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p. 1139 - 1146
(2019/08/08)
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- Isolation and identification of two new sargentodoxosides from Sargentodoxa cuneata and their agonistic effects against FXR
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Sargentodoxa cuneata (Oliv.) Rehd. et Wils is a traditional Chinese medicine to treat acute appendicitis, rheumarthritis, abdominal pain, and painful menstruation for a long history. The investigation of S. cuneata led to the isolation and identification of twenty-three secondary metabolites, including two new compounds, sargentodoxosides A (1) and B (2), and twenty-one known ones (3-23). Their structural characterization was conducted by HRESIMS, 1 D and 2 D NMR spectra. All the isolated compounds were assayed for their agonistic activities against the farnesoid X receptor (FXR). Nine of the isolated compounds displayed significant agonistic effects against FXR at 0.1 μM, suggesting that they could be served as potential agents for the development of FXR agonists.
- Zhang, Wen,Sun, Cheng-Peng,Peng, Yu-Lin,Zhao, Wen-Yu,Wang, Zheng-Yue,Ning, Jing,Lv, Xia,Yu, Zhen-Long,Zhou, Shuang,Peng, Wei,Fang, Bang-Jiang,Ma, Xiao-Chi
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- Discovery of New Iridoids as Farnesoid X Receptor Agonists from Morinda officinalis: Agonistic Potentials and Molecular Stimulation
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The investigation of Morinda officinalis led to the isolation of twelve compounds (1—12), including three new iridoid glycosides morindalins A—C (1—3) and nine known compounds (4—12). Their structural identifications were conducted using HRMS, 1D and 2D NMR, and electronic circular dichroism (ECD) spectra as well as quantum chemical computations. Compound 6 displayed the most significantly agonistic activity against farnesoid X receptor (FXR) with an EC50 value of 7.18 μM, and its agonistic effect was verified through the investigation of FXR downstream target genes including small heterodimer partner 1 (SHP1), bile salt export pump (BSEP), and organic solute transporter subunit alpha and beta (OSTα and OSTβ). The potential interaction of compound 6 with FXR was analyzed by molecular docking and molecular dynamics stimulation, revealing that amino acid residues Leu287, Thr288, and Ser332 played a crucial role in the activation of compound 6 towards FXR. These findings suggested that compound 6 could be regarded as a potential candidate for the development of FXR agonists.
- Luan, Zhi-Lin,Qiao, Fei,Zhao, Wen-Yu,Ming, Wen-Hua,Yu, Zhen-Long,Liu, Jie,Dai, Sheng-Yun,Jiang, Shuang-Hui,Lian, Chao-Jie,Sun, Cheng-Peng,Zhang, Bao-Jing,Zheng, Jian,Ma, Shuang-Cheng,Ma, Xiao-Chi
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p. 1288 - 1296
(2021/05/06)
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- A novel acylated flavonol tetraglycoside and rare oleanane saponins with a unique acetal-linked dicarboxylic acid substituent from the xero-halophyte Bassia indica
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In recent years, the scientific interest and particularly the economic significance of halophytic plants has been highly demanding due to the medicinal and nutraceutical potential of its bioactive compounds. A xero-halophyte Bassia indica is deemed to be
- Othman, Ahmed,Amen, Yhiya,Shimizu, Kuniyoshi
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- Polyacetylenes and Flavonoids Isolated from Flowers of Carthamus tinctorius
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A new acetylene, (8S)-deca-4,6-diyne-1,8-di-O-β-D-glucopyranoside (4), and four known polyacetylenes (1–3 and 5), together with nine known flavonoids (6–14), were isolated from the flowers of Carthamus tinctorius L. The structures of the isolates were elucidated by using spectroscopic analysis, mainly 1D and 2D NMR, HR-MS, and comparison with literature data, as well as enzymatic hydrolysis and Mosher′s esterification methods. All isolated compounds were evaluated for their anti-allergic effects by analyzing the inhibition of interleukin-2 (IL-2) expression in Jurkat T cells. Among them, 6-hydroxykaempferol 3,6-diglucoside (7) inhibited IL-2 production in activated T cells.
- Cao, Thao Quyen,Kim, Jeong Ah,Min, Byung Sun,Ngo, Thi Men,Vu, Thi Oanh
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p. 635 - 640
(2021/07/17)
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- The neurotrophic and antineuroinflammatory effects of phenylpropanoids from Zanthoxylum nitidum var. tomentosum (Rutaceae)
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Three novel lignans (1, 5 and 6) and two novel quinic acids (16 and 17) along with 15 known phenylpropanoids were obtained from the ethanol extract of Zanthoxylum nitidum var. tomentosum (Rutaceae). Their structures were confirmed by comprehensive spectroscopic data (NMR and HRESIMS), and the absolute configurations of all novel compounds were elucidated based on electronic circular dichroism (ECD) spectroscopic data. The production of nitric oxide (NO) in BV-2 microglial cells induced through lipopolysaccharide (LPS) was used to evaluate in vitro anti-neuroinflammatory activity of compounds 1–20. Compound 2, 3, 7 and 16 showed excellent inhibition of LPS-induced NO production. The structure-activity relationships of the isolates were investigated. In addition, the mechanism of action of 2 was elucidated by RT-PCR and Western blotting analysis, which indicated that it reduced neuroinflammatory mainly through NLRP3/caspase1 signaling pathways in LPS-induced BV2 microglial cells.
- Chen, Yao,Fan, Cai-Wen,Huang, Xiao-chao,Li, Mei-Shan,Qin, Feng,Wang, Chun-Gu,Wang, Fan-Fan,Wang, Heng-Shan,Zhu, Yan-Kui
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- New benzoic acid and caffeoyl derivatives with anti-inflammatory activities isolated from leaves of Ilex kaushue
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A new benzoic acid, 3-[2-(2-hydroxyphenyl)acetoxy]benzoic acid (1), and two new caffeoyl derivatives, methyl (3E,5Z)-di-O-caffeoylquinate (2) and dhurrin 6′-O-caffeate (3), along with 20 known compounds were isolated from the leaves of Ilex kaushue collected in Vietnam. Their structures were elucidated on the basis of 1 D and 2 D NMR spectroscopy, and high-resolution MS spectrometry. The absolute configuration of 2 and 3 was unambiguously established by comparison of experimental and calculated ECD spectra and/or chemical reactivity. In addition, new compounds were evaluated for inhibitory effects of their tumor necrosis factor-α (TNF-α) production and cell cytotoxicity on lipopolysaccharide-induced RAW264 macrophage cells. All of those moderately suppressed TNF-α production in ratios of approximately 50% or higher at 25–100 μM, without cell cytotoxicity.
- Kakumu, Yuya,Mitsunaga, Tohru,Nguyen, Thi Minh Tu,Yamauchi, Kosei
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- Enzyme aggregation and fragmentation induced by catalysis relevant species
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It is usually assumed that enzymes retain their native structure during catalysis. However, the aggregation and fragmentation of proteins can be difficult to detect and sometimes conclusions are drawn based on the assumption that the protein is in its native form. We have examined three model enzymes, alkaline phosphatase (AkP), hexokinase (HK) and glucose oxidase (GOx). We find that these enzymes aggregate or fragment after addition of chemical species directly related to their catalysis. We used several independent techniques to study this behavior. Specifically, we found that glucose oxidase and hexokinase fragment in the presence ofd-glucose but notl-glucose, while hexokinase aggregates in the presence of Mg2+ion and either ATP or ADP at low pH. Alkaline phosphatase aggregates in the presence of Zn2+ion and inorganic phosphate. The aggregation of hexokinase and alkaline phosphatase does not appear to attenuate their catalytic activity. Our study indicates that specific multimeric structures of native enzymes may not be retained during catalysis and suggests pathways for different enzymes to associate or separate over the course of substrate turnover.
- Adair, James,Bhide, Ashlesha,Gentile, Kayla,Ghosh, Subhadip,Kauffman, Joshua,Lee, Tae-Hee,Maiti, Subhabrata,Sen, Ayusman
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p. 20709 - 20717
(2021/10/02)
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- New flavone C-glycosides from Scleranthus perennis and their anti-collagenase activity
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Three new flavone glycosides, one known flavone glycoside, and the phenolic derivative apiopaenonside were isolated and identified from the ethyl acetate fraction of the aerial parts of Scleranthus perennis. The planar structures were elucidated through e
- Granica, Sebastian,Jakimiuk, Katarzyna,Strawa, Jakub W.,Tomczyk, Micha?
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- Two new ionones from the fresh roots of Rehmannia glutinosa
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Two new ionones, frehmaglutin F (1) and frehmaglutin G (2), along with eight known compounds (3–10) were isolated from the EtOAc extract of the fresh roots of Rehmannia glutinosa. All the structures were established by interpretation of the MS and NMR spe
- Cao, Yan-gang,Chen, Xu,Fan, Xi-ling,Feng, Wei-sheng,He, Chen,Liu, Yan-ling,Ren, Ying-jie,Zeng, Meng-nan,Zhang, Yu-han,Zheng, Xiao-ke
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p. 114 - 118
(2021/10/20)
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- Secoiridoid dimers and their biogenetic precursors from the fruits of Cornus officinalis with potential therapeutic effects on type 2 diabetes
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Cornusdiridoid A-F (1–6), six unusual cornuside-morroniside secoiridoid dimers, and their possible new biogenetic precursor, 3″,5″-dehydroxycornuside (7), together with four known secoiridoids (8–11), were obtained from the fruits of Cornus officinalis. Their structures were elucidated on the basis of various spectroscopic and chemical methods. A plausible biosynthetic pathway of compounds 1–11 was proposed. The α-glucosidase inhibitory, antioxidant and anti-inflammatory activities of these isolates were evaluated. Some of them emerged out as potent antidiabetic, anti-inflammatory and free radical scavenging agents. Molecular docking was also carried out for antidiabetic target α-glucosidase to investigate the possible binding modes of the most potent α-glucosidase inhibitor, vincosamide (9). These results revealed that the secoiridoids from C. officinalis fruits may be served as new potential antidiabetic agents to prevent and treat type 2 diabetes.
- Peng, Zhong-Can,He, Jun,Pan, Xue-Ge,Zhang, Jia,Wang, Yu-Ming,Ye, Xian-Sheng,Xia, Cong-Yuan,Lian, Wen-Wen,Yan, Yu,He, Xiao-Li,Zhang, Wei-Ku,Xu, Jie-Kun
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- Acylated pelargonidin and cyanidin 3-sambubiosides from the flowers of Aeschynanthus species and cultivars
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Thirteen anthocyanins were isolated from the flowers of two Aeschynanthus species, A. fulgens and A. pulcher, and six cultivars, ‘Mahligai’, ‘Mona Lisa’, ‘SoeKa’, ‘Redona’, ‘Freshya’ and ‘Bravera’, and identified as pelargonidin and cyanidin 3-O-sambubiosides and their malonates, succinates, p-coumarates and caffeates, and pelargonidin 3-O-glucoside by acid hydrolysis, HR-MS and NMR. Of their anthocyanins, pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-malonylglucoside)] (2), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-succinylglucoside)] (3), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-E-p-coumaroylglucoside)] (4), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-Z-p-coumaroylglucoside)] (5), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-E-caffeoylglucoside)] (6) and cyanidin 3-O-[xylosyl-(1 → 2)-(6''-succinylglucoside)] (9) were reported in nature for the first time.
- Iwashina, Tsukasa,Mizuno, Takayuki,Rahayu, Sri,Sugahara, Kohtaro,Tsutsumi, Chie,Widyatmoko, Didik
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- Solvent-Dependent Mechanism and Stereochemistry of Mitsunobu Glycosylation with Unprotected Pyranoses
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An SN2 mechanism was proposed for highly stereoselective glycosylation of benzoic acid with unprotected α-d-glucose under Mitsunobu conditions in dioxane, while an SN1 mechanism was indicated for nonstereoselective glycosylation in DMF. The SN2-type stereoselective Mitsunobu glycosylation is generally applicable to various unprotected pyranoses as glycosyl donors in combination with a wide range of acidic glycosyl acceptors such as carboxylic acids, phenols, and imides, retaining its high stereoselectivity (33 examples). Glycosylation of a carboxylic acid with unprotected α-d-mannose proceeded also in an SN2 manner to directly afford a usually less accessible 1,2-cis-mannoside. One-or two-step total syntheses of five simple natural glycosides were performed using the glycosylation strategy presented here using unprotected α-d-glucose.
- Fujimori, Yusuke,Furuta, Takumi,Kawabata, Takeo,Nagaishi, Masaru,Sasamori, Takahiro,Shibayama, Hiromitsu,Takeuchi, Hironori,Tokitoh, Norihiro,Ueda, Yoshihiro,Yoshimura, Tomoyuki
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supporting information
(2020/06/29)
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- New cucurbitane type triterpenes from Momordica foetida Schumach. (Cucurbitaceae)
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Phytochemical studies on Momordica foetida led to the isolation and characterization of Momordin (23,24,25,26,27-pentanorcucurbitacin) (3), a new pentanor cucurbitane along with the known β-sitosterol 3-O-β-D-glucopyranoside (4), β-sitosterol (5) and kaempferol-7-O-?-D-glucopyranoside (6). In adition to those components, two previously unreported cucurbitane glucosides, namely 3β-hydroxy-7-oxo-23(R)-cucurbita-5,24-diene-23-O-β-D-glucopyranoside (Momordiside A) (1) and 3β-hydroxy-7β-methoxy-23(R)-cucurbita-5,24-diene-23-O-β-D-glucopyranoside (Momordiside B) (2) were also obtained. The structures were elucidated by HR-ESI-MS and spectroscopic analysis including 1D- and 2D-NMR. Compounds 1 and 2 showed significant antioxidant potential in DPPH radical scavenging assay. In addition, compound 2 further revealed significant inhibitory potential against the enzyme urease in vitro as well as moderate activity against oral cancer cell line CAL-27.
- Ahmed, Ayaz,Ali, Muhammad Shaiq,Bakang, Bruno Tchebemou,Defokou, Ulrich Dzo,Lateef, Mehreen,Nganso, Yves Oscar Ditchou,Sidjui, Lazare Sidjui,Tchouboun, Ernestine Nkwengoua,Nyassé, Barthélemy,Soh, Désiré,Teponno, Rémy Bertrand
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- A new triterpenoid saponin from Pulsatilla cernua predicted by NMR-based mosaic method
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A saponin (1) with gypsogenin as aglycone was isolated from the roots of Pulsatilla cernua. The aglycone of compound 1 was considered as gypsogenin which was rarely found in this genus. Its structure was predicted by NMR-based “mosaic” method rapidly, and further confirmed on the basis of spectroscopic data, including 2D NMR spectra and chemical evidence. This work suggested that NMR-based mosaic method is suitable for most of saponins from common species of genus Pulsatilla.
- Bao, Ying,Li, Mei-Chen,Liu, Jian-Yu,Ren, Xu-Hong,Wang, An-Dong,Wang, Xia,Xu, Yong-Nan
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supporting information
p. 909 - 914
(2018/12/14)
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- Unraveling the hydrolysis of β-1,4-glycosidic bonds in cello-oligosaccharides over carbon catalysts
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Carbon catalysts having weakly acidic groups are uniquely active for hydrolysis of cellulose to produce cello-oligosaccharides and glucose. Although adsorption of cellulose molecules on carbon is considered as the cause for this behavior, the effect of ad
- Chen, Pengru,Fukuoka, Atsushi,Shrotri, Abhijit
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p. 4593 - 4601
(2020/08/10)
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- Bioassay-guided isolation of cyclooxygenase-2 inhibitory and antioxidant phenylpropanoid derivatives from the roots of Dendropanax dentiger
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The root of Dendropanax dentiger (Harms) Merr. is a traditional Chinese medicine that has been used to treat inflammation-related diseases with little scientific validation. In this study, a bioassay-guided phytochemical investigation of D. dentiger led to the isolation of 19 phenylpropanoid derivatives including one new compound (1) and 18 known ones (2–19). Their structures were elucidated by NMR and HRMS as well as comparison with literature data. The ability of cyclooxygenase-2 (COX-2) inhibition and antioxidant of all isolated compounds were measured in vitro. Chlorogenic acid derivatives (14–19) exhibited outstanding COX-2 inhibitory (IC50 = 5.1–93.4 μM) and antioxidant (IC50 = 13.2–31.9 μM) activities. Moreover, the tight structure-activities relationships were proposed. This is the first report on the COX-2 inhibitory activity of phenylpropanoids and D. dentiger.
- He, Junwei,Liu, Ronghua,Liu, Shengzhang,Yang, Li
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- A total of eight novel steroidal glycosides based on spirostan, furostan, pseudofurostan, and cholestane from the leaves of cestrum newellii
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Previously, various steroidal glycosides were reported from plants of Cestrum species. However, phytochemical investigation has not been conducted on Cestrum newellii. A systematic phytochemical investigation of the leaves of C. newellii resulted in the isolation of eight novel steroidal glycosides (1-8), which were classified into three spirostanol glycosides (1-3), two furostanol glycosides (4 and 5), two pseudofurostanol glycosides (6 and 7), and one cholestane glycoside (8). In addition, three known cholestane glycosides (9-11) were isolated and identified. The structures of the new compounds were determined based on spectroscopic data and chemical transformations. Compounds 1 and 2 are spirostanol glycosides having hydroxy groups at C-2, C-3, C-12, and C-24 of the aglycone moiety. Although C. newellii is known to be a poisonous plant, the 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl-2H-tetrazoliumbromide assay exhibited that none of the isolated compoundswere cytotoxic to HL-60 human promyelocytic leukemia cells.
- Iguchi, Tomoki,Mimaki, Yoshihiro,Takahashi, Naoki
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- Two new lignans from the fruits of Forsythia suspensa
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Two new lignans, wikstronoside B (1) and forsysesquinorlignan (2), were isolated from the fruits of Forsythia suspensa, along with two known sesquineolignans, hedyotol A and hedyotol C (3 and 4). The structures of new compounds were established via extensive spectroscopy techniques, including UV, IR, HRESIMS, NMR, and ECD. Compounds 3 and 4 were isolated from this plant for the first time. Their anti-inflammatory effects were evaluated via a detection model with LPS-induced murine macrophage RAW264.7 cells, and compound 3 showed a moderate activity.
- Cao, Jun,Shao, Si-Yuan,Zhang, Xu,Yuan, Xiang,Feng, Zi-Ming,Jiang, Jian-Shuang,Yang, Ya-Nan,Zhang, Pei-Cheng
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p. 418 - 424
(2019/11/03)
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- Acylated iridoid glycosides with hyaluronidase inhibitory activity from the rhizomes of Picrorhiza kurroa Royle ex Benth
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Seven new acylated iridoid glycosides, picrorhizaosides A–G (1–7), were isolated from the methanol extract of the rhizomes of Picrorhiza kurroa Royle ex Benth. (Plantaginaceae), in addition to six known iridoid glycosides (8–13). The structures of these new iridoids, including their stereochemistry, were determined based on chemical and physicochemical evidence derived from NMR and MS analysis. Of the isolates, picrorhizaosides D (4, IC50 = 43.4 μM) and E (5, 35.8 μM); picrosides I (8, 60.7 μM), II (9, 22.3 μM), and IV (11, 59.2 μM); and minecoside (13, 57.2 μM), exhibited a similar or stronger hyaluronidase inhibitory activity than those of the antiallergic medicines disodium cromoglycate (64.8 μM), ketotifen fumarate (76.5 μM), and tranilast (227 μM).
- Morikawa, Toshio,Nakanishi, Yusuke,Inoue, Naoki,Manse, Yoshiaki,Matsuura, Hideyuki,Hamasaki, Shinya,Yoshikawa, Masayuki,Muraoka, Osamu,Ninomiya, Kiyofumi
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- Two new benzophenone glycosides from the aerial parts of Hypericum przewalskii
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Plants of the genus Hypericum contain various types of secondary metabolites that exhibited extensive biological activities. In the ongoing efforts to discover natural neuroinflammatory inhibitors with the potential to develop into therapeutic agents for neurodegenerative diseases, two new benzophenone glycosides, hyperewalones A and B (1 and 2), along with eight known compounds (3–10), were isolated from the aerial parts of Hypericum przewalskii. Their structures were elucidated by comprehensive analysis of IR, HRESIMS, 1D and 2D NMR spectra, and chemical derivatization. The anti-neuroinflammatory activity of compounds 1–10 was evaluated by determining their ability to inhibit the production of nitric oxide (NO) in lipopolysaccharide (LPS)-activated BV-2 microglial cells. Compounds 2, 4, 6–8 exhibited significant anti-neuroinflammatory activity with IC50 values of 0.61–4.90 μM. These findings suggest that the benzophenone, ionone, and flavonoid glycosides isolated from H. przewalskii are promising anti-neuroinflammatory compounds worthy of further investigations.
- Xie, Jin-Yan,Jin, Qinghao,Gao, Jin-Ming,Zong, Shi-Chun,Yan, Xi-Tao
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supporting information
(2021/01/05)
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- New pregnane glycosides from Caralluma hexagona Lavranos and their in vitro α-glucosidase and pancreatic lipase inhibitory effects
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Three new pregnane glycosides in addition to four known compounds were isolated from the methylene chloride fraction of Caralluma hexagona Lavranos using bioassay-guided fractionation. The new compounds were identified as 12,20-di-O-benzoyl-3β,8β,12β,14β,20-pentahydroxy-(20R)-pregn-5-ene-3-O-β-D-glucopyranosyl-(1→4)-β-D-digitaloside (1), 3β,8β,14β,20-tetrahydroxy (20R)-pregn-5-ene-3-O-β-D-glucopyranosyl-(1→4)-O-β-D-digitaloside-20-O-β–D-glucopyranoside (2), 3β,8β,14β,20-tetrahydroxy-(20R)-pregn-5-ene-3-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl-(1→4)-O-β-D-digitaloside-20-O-β–D-glucopyranoside (3), along with the known compounds luteolin 4`-O-neohesperidoside (4), apigenin-8-C-neohesperoside (5), β-sitosterol (6) and β-sitosterol glucoside (7). Preliminary studies of the crude methanolic extract and methylene chloride fraction showed inhibitory effects against α-glucosidase and pancreatic lipase. Among the isolated compounds, compound 5 showed the most potent α-glucosidase inhibition with IC50 value of 0.82 ± 2.50 μM compared to acarbose (0.81 ± 0.86 μM). Whereas compound 1 showed the highest inhibitory activity on pancreatic lipase with an IC50 value of 23.59 ± 2.49 μM compared to orlistat (7.41 ± 2.26 μM).
- Abdel-Sattar, Essam,Choucry, Mouchira A.,El Halawany, Ali M.,El-Sakhawy, Fatma S.,Ki, Dae-Won,Morita, Hiroyuki,Shalabi, Akram A.
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- Triterpene saponins from Silene gallica collected in North-Eastern Algeria
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Eleven previously undescribed triterpene saponins, named silenegallisaponin A-K (1–11), were isolated from the aerial parts of Silene gallica L. Their structures were elucidated by analysis of 1D and 2D-NMR spectroscopic data and mass spectrometry (HR-ESI-MS). The saponins comprised caulophyllogenin, echinocystic acid, or quillaic acid substituted at C-3 by a β-D-glucuronic acid or β-D-galactopyranosyl-(1 → 3)-β-D-glucuronopyranoside and at C-28 by a β-D-fucopyranose substituted at C-2 by a β-D-glucose and at C-3 by a β-D-glucose or a β-D-quinovose.
- Bechkri, Sara,Alabdul Magid, Abdulmagid,Sayagh, Charlotte,Berrehal, Djemaa,Harakat, Dominique,Voutquenne-Nazabadioko, Laurence,Kabouche, Zahia,Kabouche, Ahmed
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- Mechanistic insights into enzymatic catalysis by trehalase from the insect gut endosymbiont Enterobacter cloacae
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Energy metabolism in the diamondback moth Plutella xylostella is facilitated by trehalase, an enzyme which assists in trehalose hydrolysis, from the predominant gut bacterium Enterobacter cloacae. We report the biochemical and structural characterization of recombinant trehalase from E. cloacae (Px_EclTre). Px_EclTre showed KM of 1.47 (±0.05) mm, kcat of 6254.72 min?1 and Vmax 0.2 (±0.002) mm·min?1 at 55 °C and acidic pH. Crystal structures of Px_EclTre were determined in the ligand-free form and bound to the inhibitor Validoxylamine A. The crystal structure of the ligand-free form, unavailable until now for any other bacterial trehalases, enabled us to delineate the conformational changes accompanying ligand binding in trehalases. Multiple salt bridges were identified that potentially facilitated closure of a hood over the substrate-binding site. A cluster of five tryptophans lined the ?1 substrate-binding subsite, interacted with crucial active site residues and contributed to both trehalase activity and stability. The importance of these residues in enzyme activity was further validated by mutagenesis studies. Many of these identified residues form part of signature motifs and other conserved sequences in trehalases. The structure analysis thus led to the assignment of the functional role to these conserved residues. This information can be further explored for the design of effective inhibitors against trehalases.
- Adhav, Anmol,Harne, Shrikant,Bhide, Amey,Giri, Ashok,Gayathri, Pananghat,Joshi, Rakesh
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p. 1700 - 1716
(2019/02/20)
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- Enzymatically Degassed Surface-Initiated Atom Transfer Radical Polymerization with Real-Time Monitoring
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Polymer brush coatings are frequently prepared by radical polymerization, a notoriously oxygen sensitive process. Glucose oxidase (GOx) can inexpensively enable radical polymerization in solution by enzymatically consuming oxygen as it oxidizes glucose. Here, we report the growth of polymeric brushes using GOx-assisted atom transfer radical polymerization (ATRP) from a surface while open to air. Specifically, we grew a set of biomedically relevant polymer brushes, including poly(oligo(ethylene glycol) methacrylate) (POEGMA), poly(2-dimethylaminoethyl methacrylate) (PDMAEMA), poly(sulfobetaine methacrylate) (PSBMA), and poly(2-(methylsulfinyl)ethyl acrylate (PMSEA). For each of these polymers, we monitored GOx-assisted and GOx-free ATRP reaction kinetics in real time using quartz crystal microbalance (QCM) and verified findings with localized surface plasmon resonance (LSPR). We modeled brush growth kinetics considering bimolecular termination. This model fit our data well (r2 > 0.987 for all samples) and shows the addition of GOx increased effective kinetic chain lengths, propagation rates, and reproducibility. We tested the antifouling properties of the polymer brush coatings against human blood plasma and were surprised to find that coatings prepared with GOx repelled more plasma proteins in all cases than their GOx-free counterparts.
- Navarro, Luis A.,Enciso, Alan E.,Matyjaszewski, Krzysztof,Zauscher, Stefan
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supporting information
p. 3100 - 3109
(2019/02/19)
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- Mechanochemistry-assisted hydrolysis of softwood over stable sulfonated carbon catalysts in a semi-batch process
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The hydrolysis of lignocellulose is the first step in saccharide based bio-refining. The recovery of homogeneous acid catalysts imposes great challenges to the feasibility of conventional hydrolysis processes. Herein, we report a strategy to overcome these limitations by using stable sulfonated carbons as solid acid catalysts in a two-step process, composed of mechanocatalytic pretreatment and secondary hydrolysis in a semi-batch reactor. Without mechanocatalytic pre-treatment the hydrolysis of the insoluble substrate largely occurs through homogeneously catalyzed reactions. Ball-milling induced amorphization promotes a substantially higher substrate reactivity, because homogeneous hydrolysis occurs preferentially from less ordered structural domains in cellulose. In contrast, concerted ball-milling (CBM) of cellulose with the sulfonated carbon promotes a heterogeneously catalyzed hydrolysis to soluble oligosaccharides. By performing an in-depth physicochemical characterization of cellulose subjected to CBM treatment with different carbons, we reveal the crucial role of strong Br?nsted acid sites in facilitating mechanocatalytic depolymerization. Recyclability experiments confirmed that despite being subject to profound structural changes during repeated pre-treatment/semi-batch hydrolysis cycles, the sulfonated carbon retained its catalytic activity. The combination of mechanocatalytic pretreatment with strong solid acids and hydrolysis in the semi-batch reactor was successfully extrapolated for the first time to the hydrolysis of real lignocellulose to achieve quantitative yields in C5 and high yields in C6 derived products.
- Scholz, David,Xie, Jingwei,Kr?cher, Oliver,Vogel, Frédéric
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p. 33525 - 33538
(2019/10/28)
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- WCl6 catalyzed cellulose degradation at 80?°C and lower in [BMIM]Cl
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Degradation of cellulose to reducing sugar is the key step for the conversion of cellulose to valuable chemicals. Cellulose was degraded by WCl6 in 1-butyl-3-methyl imidazole chloride at 80 °C and lower. 83% and 85.5% yield of total reducing sugar was gotten at 70 and 80 °C, respectively. Compared with inorganic acid, heteropoly acid, acidic ionic liquid and other metal chlorides, WCl6 has shown better catalytic performance for degradation of cellulose to reducing sugar. The effect of reaction temperature, reaction time, WCl6 amount and cellulose concentration were investigated. Degradation of cellulose by WCl6 in 1-butyl-3-methyl imidazole chloride is a zero reaction. WCl6 also showed excellent catalytic performance for the degradation of nature cellulose and lignocellulose. Catalyst can be reused at least 5 times without decrease of reducing sugar yield. The mechanism of degradation of WCl6 was also suggested.
- Zhou, Lilong,Zhang, Shanshan,Li, Zhengjie,Zhang, Zhikun,Liu, Runjing,Yun, Jimmy
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p. 289 - 296
(2019/02/25)
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- Carbon Materials as Phase-Transfer Promoters for Obtaining 5-Hydroxymethylfurfural from Cellulose in a Biphasic System
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Different carbonaceous materials were tested as mass-transfer promoters for increasing the yield of 5-hydroxymethylfurfural (5-HMF) in biphasic cellulose hydrolysis. The benefits of working with a biphasic system (water/methyl isobutyl ketone) under soft acid conditions were taken as starting point (no humins or levulinic acid production), with slow extraction kinetics as the weakest point of this approach. Carbon nanotubes (CNTs) and activated carbon (AC) were proposed to improve 5-HMF liquid–liquid mass transfer. A kinetic analysis of the extraction process indicated the competition between 5-HMF and glucose adsorption as the main cause of the poor results obtained with AC. In contrast, very promising results were obtained with CNTs, mainly at 1.5 wt % loading, with complete transfer of HMF and a high global mass-transfer coefficient. The use of CNTs improved the amount of 5-HMF in the organic phase by more than 270 %.
- Faba, Laura,Garcés, Diego,Díaz, Eva,Ordó?ez, Salvador
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p. 3769 - 3777
(2019/07/04)
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- Hederagenin glycosides from the fruits of Blighia unijugata
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A phytochemical investigation of Blighia unijugata led to the isolation of eleven hederagenin glycosides. Among these compounds, six are previously undescribed, two are described in their native forms for the first time and three are known whereas firstly isolated from Blighia unijugata. The structure of the undescribed compounds was elucidated on the basis of 2D NMR and mass spectrometry analyses as 3-O-β-D-xylopyranosyl-(1 → 3)-α-L-arabinopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin, 3-O-β-D-xylopyranosyl-(1 → 3)-α-L-arabinopyranosyl-(1 → 4)-3-O-acetyl-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin, 3-O-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin, 3-O-β-D-xylopyranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin, 3-O-β-D-xylopyranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-3-O-acetyl-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin, 3-O-α-L-arabinopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin 28-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl ester, 3-O-α-L-arabinopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin 28-O-β-D-glucopyranosyl ester and 3-O-β-D-xylopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin 28-O-β-D-glucopyranosyl ester. These results revealed the existence of several conserved structural features that could be used as chemotaxonomic markers for the Blighia genus such as the glycosidic sequence 3-O-α-L-arabinopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl, the occurrence of 3-O-acetylated β-D-glucopyranosyl units and the systematic presence of hederagenin as aglycone.
- Petit, Bastien,Mitaine-Offer, Anne-Claire,Delaude, Clément,Miyamoto, Tomofumi,Tanaka, Chiaki,Lacaille-Dubois, Marie-Aleth
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p. 260 - 269
(2019/05/01)
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- New Acylated Phenolic Glycosides with ROS-Scavenging Activity from Psidium guajava Leaves
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Reactive oxygen species and subsequent oxidative stress are reported to play important roles in chronic metabolic diseases. Plant-derived polyphenols, especially food-derived phenolics, have attracted a lot of attention due to their potential usage against oxidative stress-related diseases. The leaf of Psidium guajava (known as guava) is regarded as a good resource of polyphenols and its products are commercially available in Japan as functional foods against multiple chronic metabolism disorders. In the course of finding novel polyphenols with antioxidative activities from guava leaf, 11 acylated phenolic glycosides (1-11), including 5 new oleuropeic acid-conjugated phenolic glycosides, named guajanosides A-E (1, 2, and 5-7), along with 17 known meroterpenoides (12-28), were isolated and identified. Their structures were determined by spectroscopic data analysis, chemical degradation, and acid hydrolysis. Compounds 1, 2, and 5-11 displayed potent reactive oxygen species-scavenging activity in lipopolysaccharide-stimulated RAW 264.7 macrophage cells. Western blot revealed that compound 6 markedly increased the expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), and the glutamate-cysteine ligase catalytic subunit. The current study revealed the presence of oleuropeic acid-derived phenolic glycosides in guava leaf and highlighted the potential usage of this type of phenolics against oxidative stress-related metabolic diseases via activation of the Nrf2 signaling pathway.
- Li, Yuanyuan,Li, Dongli,An, Qi,Ma, Hang,Mu, Yu,Qiao, Wenjun,Zhang, Zengguang,Zhang, Jingsheng,Huang, Xueshi,Li, Liya
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p. 11089 - 11098
(2019/10/11)
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- Chemical constituents from the twigs and leaves of Trichilia sinensis and their biological activities
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Phytochemical investigation on the twigs and leaves of Trichilia sinensis led to the isolation of two previously undescribed limonoids (i.e., trichiliasinenoids D and E, 1 and 2), two previously undescribed phenolic acids (3 and 4), and one previously undescribed natural phenolic acid dimer (5), together with 11 known compounds (6-16). Their structures were elucidated by extensive spectroscopic analysis (IR, UV, HRESIMS, 1D and 2D NMR) and chemical techniques. The potential anti-inflammatory activities of all the compounds were evaluated in lipopolysaccharide-stimulated RAW 264.7 cells. Among these isolates, compounds 1, 2, 6, and 11-13 expressed weak NO inhibition. The antibacterial activities of all the compounds against bacteria were also tested in vitro. Compound 16 exhibited moderate antibacterial activities against Escherichia Coli.
- Cao, Dong-Hua,Sun, Peng,Liao, Shang-Gao,Gan, Li-She,Yang, Lin,Yao, Jian-Neng,Zhang, Zong-Yi,Li, Jin-Feng,Zheng, Xiao-Ling,Xiao, Yi-Dian,Xiao, Chun-Fen,Zhang, Ping,Hu, Hua-Bin,Xu, You-Kai
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p. 142 - 147
(2018/12/11)
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- Structural determination of ananatoside A: An unprecedented 15-membered macrodilactone-containing glycolipid from Pantoea ananatis
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The bacterium Pantoea ananatis was reported to produce glycolipid biosurfactants of unknown structures. Herein, we present the isolation and structural determination of ananatoside A, the main congener of a new family of 15-membered macrodilactone-containing glucolipids. The structure of ananatoside A was elucidated via chemical degradation and spectroscopic methods including 1D/2D NMR analysis, tandem MS/MS, GC-MS, HR-ESI-TOF-MS, MALDI-TOF-MS, and polarimetry. Computational methods were used to predict the most abundant conformers of ananatoside A.
- Gauthier, Charles,Lavoie, Serge,Piochon, Marianne,Martinez, Sarah,Milot, Sylvain,Déziel, Eric
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- Structures and biological evaluation of phenylpropanoid derivatives from Murraya koenigii
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Four new phenylpropanoid derivatives (1–4), together with eleven known analogues (5–15) were isolated and identified by comparison with their references and extensive spectroscopic methods from Murraya koenigii for the first time. Compounds (1–15) were assayed for their inhibitory activities by measuring IL-6-induced STAT3 promoter activities in HepG2 cells, and found compounds 1, 2, 6, and 15 showed inhibitory effects with IC50 values of 11.5, 18.7, 8.9, and 22.7 μM, respectively. The inhibitory activities of compounds (1–15) were screened against NO production in lipopolysaccharide (LPS)-induced RAW264.7 macrophage cells, and found compounds 3, 4, 9, 11, and 14 exhibited inhibitions against LPS-induced NO production in RAW264.7 macrophages, with IC50 values of 32.7, 7.9, 42.1, 58.9, and 62.4 μM, respectively.
- Ma, Qinge,Wei, Rongrui,Yang, Ming,Huang, Xiaoying,Zhong, Guoyue,Sang, Zhipei,Dong, Jianghong,Shu, Jicheng,Liu, Jianqun,Zhang, Rui,Yang, Jianbo,Wang, Aiguo,Ji, Tengfei,Su, Yalun
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p. 159 - 165
(2019/02/03)
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- A Systematic Study of Metal Triflates in Catalytic Transformations of Glucose in Water and Methanol: Identifying the Interplay of Br?nsted and Lewis Acidity
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The specific type of acidity associated with the given metal trifloromethanesulfonates (Br?nsted or Lewis acidity) dramatically influences the course of reactions, and it is possible to select for disaccharides, fructose, methyl glucosides, or methyl levulinate. Glucose is transformed into a range of value-added molecules in water and methanol under the action of acidic metal triflates as catalysts, including their analogous Br?nsted acid-assisted or Br?nsted base-modified systems. A systematic study is presented of a range of metal triflates in methanol and water, pinning down the preferred conditions to select for each product.
- Bodachivskyi, Iurii,Kuzhiumparambil, Unnikrishnan,Williams, D. Bradley G.
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- Bioactivity-Guided Isolation and Identification of Antiadipogenic Compounds in Shiya Tea (Leaves of Adinandra nitida)
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Obesity is a worldwide epidemic contributing to a higher risk of developing maladies such as type 2 diabetes, heart disease, and cancer. Shiya tea (leaves of Adinandra nitida), a traditional Chinese tea, is widely consumed due to its palatable flavor and various curative effects, such as reducing blood pressure and blood lipids, as well as anti-inflammation, etc. However, no relevant research on the antiobesity effects of Shiya tea has been reported. In particular, no health-benefiting compounds, other than flavonoids, in Shiya tea have been reported. Thus, 3T3-L1 preadipocytes have been used as a bioactivity-guided identification model to verify the inhibitory effects of Shiya tea on adipogenesis, as well as to identify antiadipogenic compounds. Four triterpenoid saponins (1-4), including one new compound (2α,3α-dihydroxyursolic acid 28-O-β-d-glucopyranosyl ester, compound 1), and a flavonoid (5) have been identified using NMR (1D and 2D NMR) and liquid chromatography (LC)-MS techniques. Compound 1, the major antiadipogenic constituent with an IC50 value of 27.6 μg/mL, has been identified for the first time in Shiya tea. To understand the structure-activity relationship, three hydrolytic compounds (1s, 2s, and 5s) were obtained to provide an inhibitory effect on lipid accumulation during 3T3-L1 adipocyte differentiation. The inhibitory effect of the triterpenoid (1s) possessing no sugar group decreased significantly, while the flavonoid (5s) also without a sugar group showed increased activity. In addition, the hydroxyl group position may also play a role in inhibitory efficacy.
- Yuan, Chunmao,Huang, Linhua,Suh, Joon Hyuk,Wang, Yu
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- Phytochemical studies on the Australian native plant species Acacia pycnantha and Jacaranda mimosifolia D.Don*
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In ongoing investigations into colours in Nature, the chemical constituents from the flowers of Acacia pycnantha and Jacaranda mimosifolia D.Don grown in Australia are reported. Eight known secondary metabolites were isolated from the A. pycnantha flower including isosalipurposide (7) which may be responsible for their distinctive colouration. Nine secondary metabolites were isolated from the J. mimosifolia D.Don flower including the new phenylethanoid β-D-glucopyranose (10). All isolated compounds were inactive against bacteria tested at concentration of 32?μg/mL.
- Hendra, Rudi,Willis, Anthony,Keller, Paul A.
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supporting information
p. 1997 - 2003
(2018/06/18)
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- Antihyperlipidemic glycosides from the root bark of Lycium chinense
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Three new glycosides (1–3), together with six known ones (4–9), were isolated from the root bark of Lycium chinense. Their structures were elucidated on the basis of MS and NMR spectroscopic data. Five compounds (3, 5, 6, 8, and 9) exhibited potent antihyperlipidemic activities in HepG2 cells as assessed by Oil Red O staining and significant inhibition of intracellular triglyceride (TG) levels, whereas two compounds (5 and 9) significantly reduced total cholesterol (TC) levels.
- Chen, Hui,Li, Yu-Jie,Sun, Yan-Jun,Li, Xiao-Kun,Jian-Hong, Gong,Wu, Ya,Su, Fang-Yi,Du, Kun,Zhang, Yan-Li,Feng, Wei-Sheng
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p. 2655 - 2661
(2018/05/15)
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- Flavonoid glycosides from seeds of Hippophae rhamnoides subsp. Sinensis with α-glucosidase inhibition activity
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Hippophae rhamnoides subsp. Sinensis is a famous traditional medicinal plant in Tibet and Mongolia of China. Three novel flavonoid glycosides and ten known analogues were obtained from the seeds of H. rhamnoides. The structures of new compounds were elucidated by spectroscopics, chemical methods as well as literature data. In vitro assay, compounds 5–9, kaempferol and 70% ethanolic elution fraction showed prominent α-glucosidase inhibitory activities with IC50 values ranging from 8.30 to 112.11 μM, better than that of the positive control, acarbose, whose IC50 value was 1727.07 μM.
- Li, Rui,Wang, Qing,Zhao, Menghao,Yang, Peiming,Hu, Xiao,Ouyang, Danwei
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- New hexalactone derivatives and a pair of new oxaspiro-carbon epimeric glycosides from the fruits of Illicium lanceolatum
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Five new compounds (1–5), including three hexalactone derivatives (1–3) and a pair of new oxaspiro-carbon epimeric glycosides (4 and 5), and six known compounds (6–11) were obtained from the fruits of Illicium lanceolatum. The structures of the new compounds were elucidated using extensive spectroscopic data. The absolute configurations of compounds 1–3 were determined by an analysis of their CD spectra. It was determined that compounds 4 and 5, which are epimeric at C-5, possess the same 1-oxaspiro[4,5]decane-7α,8α,9β-triol moiety. Plausible biogenetic pathways for 4 and 5 derived from the key precursor shikimic acid were proposed. Compounds 1–11 were all assayed on monosodium glutamate-induced human neuroblastoma SH-SY5Y cell damage. The results demonstrated that compounds 4, 5, and 8–10 possess potential neuroprotective effects. The anti-inflammatory, antiviral, and cytotoxic activities of 1–11 were also evaluated.
- Liu, Yang-Lan,Wang, Xiao-Jing,Wang, Ru-Bing,Li, Mi,Li, Wen-Rui,Zhang, Jian-Pei,Bao, Xiu-Qi,Zhang, Dan,Ma, Shuang-Gang
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- Discovery of Neolignan Glycosides with Acetylcolinesterase Inhibitory Activity from Huangjinya Green Tea Guided by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry Data and Global Natural Product Social Molecular Networking
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Global Natural Product Social feature-based networking was applied to follow the phytochemicals, including nine flavonoid glycosides, six catechins, and three flavonols in Huangjinya green tea. Further, a new 8-O-4′-type neolignan glycoside, camellignanoside A (1), and 15 known compounds (2-16) were isolated through a variety of column chromatographies, and the structure was elucidated extensively by ultra performance liquid chromatography-quadrupole-time-of-flight-tandem mass spectrometry, 1H and 13C nuclear magnetic resonance, heteronuclear single-quantum correlation, heteronuclear multiple-bond correlation, 1H-1H correlation spectroscopy, rotating frame nuclear Overhauser effect spectroscopy, and Nuclear Overhauser effect spectroscopy, and circular dichroism spectroscopies. Compounds 1 and 2 showed acetylcolinesterase inhibition activity, with IC50 = 0.75 and 0.18 μM, respectively.
- Wu, Hao-Yue,Ke, Jia-Ping,Wang, Wei,Kong, Ya-Shuai,Zhang, Peng,Ling, Tie-Jun,Bao, Guan-Hu
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- An acid-stable β-glucosidase from Aspergillus aculeatus: Gene expression, biochemical characterization and molecular dynamics simulation
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β-Glucosidases hydrolyze terminal, non-reducing β-D-glucosyl residues and thereby release β-D-glucose. They have applications in the production of biofuels, beverages and pharmaceuticals. In this study, a β-glucosidase derived from Aspergillus aculeatus (BGLA) was expressed, characterized, and the molecular mechanism of its acid denaturation was comprehensively probed. BGLA exhibited maximal activity at pH 5.0–6.0. Its optimal temperature was 70 °C. Its enzyme activity was enhanced by Mg2+, Ca2+ and Ba2+, while Cu2+, Mn2+, Zn2+, Fe2+ and Fe3+ had a negative effect. BGLA showed activity on a broad range of substrates including salicin, cellobiose, arbutin, geniposide and polydatin. Finally, the acid-denaturation mechanism of BGLA was probed using molecular dynamics (MD) simulations. The results of simulation at pH 2.0 imply that the contact number, solvent accessible surface area and number of hydrogen bonds in BGLA decreased greatly. Moreover, the distance between the residues Asp280 and Glu509 that are part of the active site increased, which eventually destroyed the enzyme's catalytic activity. These MD results explain the molecular mechanism of acid denaturation of BGLA, which will greatly benefit the rational design of more acid-stable β-glucosidase variants in the future.
- Li, Yu,Hu, Xiaoyan,Sang, Jingcheng,Zhang, Ying,Zhang, Huitu,Lu, Fuping,Liu, Fufeng
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p. 462 - 469
(2018/08/03)
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- Br?nsted acidic ionic liquids for cellulose hydrolysis in an aqueous medium: Structural effects on acidity and glucose yield
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The conversion of cellulose into valuable chemicals has attracted much attention, due to the concern about depletion of fossil fuels. The hydrolysis of cellulose is a key step in this conversion, for which Br?nsted acidic ionic liquids (BAILs) have been considered promising acid catalysts. In this study, using BAILs with various structures, their acidic catalytic activity for cellulose hydrolysis assisted by microwave irradiation was assessed using the Hammett acidity function (H0) and theoretical calculations. The glucose yields exceeded 10% when the H0 values of the BAIL aqueous solutions were below 1.5. The highest glucose yield was about 36% in 1-(1-octyl-3-imidazolio)propane-3-sulfonate (Oimps)/sulfuric acid (H2SO4) aqueous solution. A long alkyl side chain on the imidazolium cation, which increased the hydrophobicity of the BAILs, enhanced the glucose yield.
- Suzuki, Shiori,Takeoka, Yuko,Rikukawa, Masahiro,Yoshizawa-Fujita, Masahiro
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p. 14623 - 14632
(2018/04/26)
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