- A straightforward synthesis of natural oxygenated ent-kaurenoic acid derivatives
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The paper presents the synthesis of some natural diterpenoids of ent-kauranic structure, starting from ent-kaur-16-en-19-oic acid, a natural diterpenoid readily available from the dried wastes of sunflower (Helianthus annuus L.). The reported ent-16α,17-dihydroxykauran-19-oic, ent-16α-hydroxy-17-acetoxykauran-19-oic and ent-16α,17-diacetoxykauran-19-oic acids have been previously isolated from different plant sources and showed diverse biological activities, including anti-HIV, anti-cancer and anti-Alzheimer properties. Their chemical synthesis has not been disclosed so far. Additional cytotoxicity studies of the obtained compounds revealed a remarkable cell proliferative effect of parent ent-kaur-16-en-19-oic acid and two of its synthetic derivatives, which is in line with recent pioneering studies in this area.
- Morarescu, Olga,Grinco, Marina,Kulci?ki, Veaceslav,Barba, Alic,Garbuz, Olga,Gudumac, Valentin,Gulea, Aurelian,Ungur, Nicon
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- THE MICROBIOLOGICAL TRANSFORMATION OF TWO ENT-16β,17-EPOXYKAURANE DERIVATIVES BY GIBBERELLA FUJIKUROI
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The biotransformation of ent-16β,17-epoxy-7α-hydroxykaurane by Gibberella fujikuroi affords ent-7α,11α,16β,17-tetrahydroxykaurane and ent-7α,9α,16β,17-tetrahydroxykaurane.These results indicated that the presence of the 16α,17-diol group, into which the 16α,17-epoxy is transformed in the medium, imhibits oxidation at C-19 and favours hydroxylation at C-11(β).Incubation of ent-16β,17-epoxykauran-19-oic acid, via the 16α,17-diol, gave the 7-aldehyde of 16α,17-dihydroxy-GA12. - Key words: Gibberella fujikuroi; biotransformations; diterpenes; ent-16β,17-epoxy-7α-hydroxykaurane; ent-16β,17-epoxykauran-19-oic acid; ent-7α,16β,17-trihydroxykaurane; ent-16β,17-dihydroxykauran-19-oic acid.
- Fraga, Braulio M.,Gonzalez, Pedro,Guillermo, Ricardo,Hanson, James R.,Hernandez, Melchor G.,Takahashi, Jacqueline A.
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- A new ent-kaurane diterpene derivative from the stems of Eurya chinensis R.Br
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One new ent-kaurane diterpene derivative (1), along with four known diterpenes, was isolated from the stems of Eurya chinensis R.Br. The structure of the new compound was established by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. Compound 1 showed moderate anti-inflammatory activities with IC50 value of 8.12?μM. This is the first example of diterpenoids with 4-hydroxy-4-(2-hydroxyethyl)-1-hydroxyl-cyclohexanoyl substituent.
- Song, Jia-Ling,Yuan, Yao,Nie, Ling-Hui,Li, Bai-Lin,Qin, Xu-Bing,Li, Yan,Wu, Jie-Wei,Qiu, Sheng-Xiang
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- A new ent-kaurane diterpenoid glycoside from the leaves of Cussonia bojeri, a Malagasy endemic plant.
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A new ent-kaurane diterpene glycoside, beta-D-glucopyranosyl 17-hydroxy-ent-kauran-19-oate-16-O-beta-D-glucopyranoside (4) was isolated from the dried leaves of Cussonia bojeri SEEM., together with four known compounds identified as 16beta,17-dihydroxy-kauran-19-oic acid (1), beta-D-glucopyranosyl 16beta,17-dihydroxy-(-)-kauran-19-oate (2), paniculoside IV (3), and rutin (5). The structure of 4 was deduced on the basis of chemical and spectroscopic evidence.
- Harinantenaina, Liva,Kasai, Ryoji,Yamasaki, Kazuo
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- Oxyfunctionalization products of terpenoids with dimethyldioxirane and their biological activity
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Oxyfunctionalization of the bioactive terpenoids, ursolic acid acetate (1), oleanolic acid acetate (5), lupeol acetate (12), and kaurenic acid (17), with dimethyldioxirane (DMDO) was investigated. Treatment of the terpenoids with DMDO under mild conditions afforded a variety of oxidation and oxydegradation products to yield naturally occurring and/or novel compounds in one step. After chromatographic separation, the structures of the individual isolated products were determined using spectroscopic methods including several homonuclear ( 1H-1H) and heteronuclear (1H-13C) shift-correlated 2D-NMR techniques. The inhibitory activity of the terpenoid derivatives against α-glucosidase was investigated and compounds 1, 3, 7, and 9 were found to exhibit potent activity.
- Ogawa, Shoujiro,Hosoi, Keiji,Ikeda, Noriaki,Makino, Mitsuko,Fujimoto, Yasuo,Iida, Takashi
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p. 247 - 250
(2007/10/03)
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