- Lignan and neolignan glycosides from stems of Alangium premnifolium
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From a methanol extract of stems of Alangium premnifolium, eight lignan derivatives were isolated. Structural elucidation by a spectroscopic method revealed that four of them were new lignan or neolignan glycosides.
- Yuasa, Kaori,Ide, Toshinori,Otsuka, Hideaki,Ogimi, Choei,Hirata, Eiji,Takushi, Anki,Takeda, Yoshio
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- Pinoresinol-lariciresinol reductase: Substrate versatility, enantiospecificity, and kinetic properties
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Two western red cedar pinoresinol-lariciresinol reductase (PLR) homologues were studied to determine their enantioselective, substrate versatility, and kinetic properties. PLRs are downstream of dirigent protein engendered, coniferyl alcohol derived, stereoselective coupling to afford entry into the 8- and 8′-linked furofuran lignan, pinoresinol. Our investigations showed that each PLR homolog can enantiospecifically metabolize different furofuran lignans with modified aromatic ring substituents, but where phenolic groups at both C4/C4′ are essential for catalysis. These results are consistent with quinone methide intermediate formation in the PLR active site. Site-directed mutagenesis and kinetic measurements provided additional insight into factors affecting enantioselectivity and kinetic properties. From these data, PLRs can be envisaged to allow for the biotechnological potential of generation of various lignan skeleta, that could be differentially “decorated” on their aromatic ring substituents, via the action of upstream dirigent proteins.
- Davin, Laurence B.,Hwang, Julianne K.,Lewis, Norman G.,Moinuddin, Syed G. A.
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- Lignan Glycosides from the Twigs of Chaenomeles sinensis and Their Biological Activities
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Phytochemical investigation of the twigs of Chaenomeles sinensis led to the isolation and identification of six new lignan glycosides, chaenomiside A-F (1-6), along with five known ones (7-11). Their chemical structures were determined by spectroscopic methods, including NMR, MS, ECD, and GC/MS analyses. All the isolated compounds (1-11) were tested for their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide-activated murine microglial cells and the secretion of nerve growth factor (NGF) in a C6 rat glioma cell line. Compound 6 significantly reduced NO levels in the murine microglia BV2 cells with an IC50 value of 21.3 μM, and compounds 1, 3, and 6 were potent stimulants of NGF release with stimulation levels of 151.74 ± 6.77%, 144.31 ± 7.49%, and 167.61 ± 18.5%, respectively.
- Kim, Chung Sub,Subedi, Lalita,Kim, Sun Yeou,Choi, Sang Un,Kim, Ki Hyun,Lee, Kang Ro
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supporting information
p. 1174 - 1178
(2015/06/02)
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- Lignan bis-glucosides from Galium sinaicum
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The new lariciresinol-based lignan bis-glucosides, 7S, 8R, 8'R-(-)- Iariciresinol-4,4'-bis-O-β-D-glucopyranoside and 7S, 8R, 8'R-(-)-5- methoxylariciresinol-4,4'-bis-O-β-D-glucopyranoside, together with (-)- syringaresinol-4,4'-bis-O-β-D-glucopyranoside were isolated from the n- butanol extract of Galium sinaicum roots and their structures were established by various spectroscopic techniques. The isolated compounds represent the first report of lignan glycosides from the Rubiaceae. The two lariciresinol-type glucosides exhibited weak cytotoxic activity against the P388 cell line.
- El Gamal,Takeya,Itokawa,Halim,Amer,Saad
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p. 597 - 600
(2007/10/03)
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