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Nattaya Lourith Takeshi Katayama Kimiko Ishikawa Toshisada Suzuki 《Journal of Wood Science》2005,51(4):379-386
To investigate the biosynthesis and stereochemistry of syringylglycerol-8-O-4′-(sinapyl alcohol) ether (SGSE), a syringyl 8-O-4′ neolignan, feeding experiments and enzyme assays using Eucommia ulmoides were carried out. Diastereoselective formation of erythro-SGSE was found. When [8-14C]sinapyl alcohol was administered to excised shoots of E. ulmoides, 14C was incorporated into free SGSE and SGSE glucosides. In stems, incorporation into (+)-erythro-[14C]SGSE (0.037%) with 9.1% enantiomeric excess (% e.e.) was found; incorporation into the threo isomer was not detectable. Erythro-[14C]SGSE glucosides (0.047%) dominated over threo forms (0.007%) with 74.0% diastereomeric excess (% d.e.); both diastereomers were levorotatory with 32.0% e.e. and 18.3% e.e., respectively. In leaves, higher incorporation into (−)-erythro-[14C]SGSE (0.500%, 15.9% e.e.) than into the threo isomer (0.206%, 7.4% e.e.) was observed (41.6% d.e.). (−)-Erythro-[14C]SGSE glucosides (1.692%, 25.0% e.e.) were produced at higher rates than threo isomers (0.177%, 16.4% e.e.) with 81.0% d.e. In incubations of a mixture of [8-14C]sinapyl and [8-14C]coniferyl alcohols with an insoluble enzyme preparation from stems of E. ulmoides, erythro-SGSE was preferentially produced. The highest % d.e. (82.8) was observed at 60 min with the (+)-erythro isomer (21.4% e.e.) and the (−)-threo form (4.3% e.e.).Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002, and the 47th Lignin Symposium, Fukuoka, October 2002 相似文献
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Stereochemistry and biosynthesis of guaiacylglycerol-8-O-4′-(sinapyl alcohol) ether (GGSE), an 8-O-4′ neolignan, which consists of coniferyl and sinapyl alcohol moieties, in Eucommia ulmoides were investigated. Four 8-O-4′ neolignans, GGSE, syringylglycerol-8-O-4′-(coniferyl alcohol) ether (SGCE), guaiacylglycerol-8-O-4′-(coniferyl alcohol) ether (GGCE), and syringylglycerol-8-O-4′-(sinapyl alcohol) ether (SGSE), were synthesized. Their erythro and threo diastereomers were separated through acetonide derivatives, intermediates of the synthesis, and identified by means of nuclear magnetic resonance (NMR) spectroscopy. All of the erythro-acetonide derivatives have larger coupling constants (ca 9 Hz) for the C7-H resonances than those of the threo ones (1.5–2 Hz). In the case of the four 8-O-4′ neolignans, the C7-H coupling constants of the threo-isomers are not smaller than those of the erythro ones. GGSE isolated previously from this plant was identified as the erythro isomer by comparison of the 13C-NMR data with synthetic erythro-GGSE and threo-GGSE and the other 8-O-4′ neolignans mentioned as above. Administration of a mixture of [8-14C]coniferyl alcohol and [8-14C]sinapyl alcohol to excised shoots of E. ulmoides was carried out and the incorporation of 14C into erythro-[14C]GGSE was found to be higher than that in threo-[14C]GGSE. The occurrence of diastereoselective formation of erythro-GGSE by cross coupling of coniferyl and sinapyl alcohols is suggested.Part of this paper was presented at the 47th Lignin Symposium, Fukuoka, October 2002 and the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, April 2003 相似文献
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The neolignan, burchellin, a natural compound that reduces urine excretion in larvae of the bloodsucking bug, Rhodnius prolixus, a vector of Chagas' disease, is rapidly degraded in the hemolymph of the insect. The main product that accumulates in this tissue has been shown to be piperonyl alcohol. Other catabolites have been identified by GC-MS analysis. 相似文献
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Two new neolignans (1 and 2) were isolated from the root bark of Illicium henryi, along with four known neolignans and seven known flavonoids (3–13). Their structures were elucidated on the basis of spectroscopic and chemical methods. The absolute configurations of compounds 1 and 2 were determined by the CD spectrum. 相似文献
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Four new neolignans, wilfordiols A-D (1-4), together with five known compounds (5-9), were isolated from an aqueous extract of the dried leaves of Tripterygium wilfordii. Their structures were determined by spectroscopic methods, including 1D and 2D NMR, HRESIMS, and CD experiments. The anti-inflammation activities of compounds 1-9 were evaluated by the inhibitory effect on NO production, in vitro. 相似文献
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Two new compounds, a neolignan (1), and a benzofuran derivative (2), along with 6 known compounds (3-8), were isolated from the aerial parts of Leontopodium leontopodioides. The structures of the new compounds were elucidated as (7R,8S)-3,5'-dimethoxy-4',7-epoxy-8,3'-neolignane-5,9,9'-triol (1) and (2R)-12-hydoxy-4-methoxy-tremeton (2) on the basis of their spectroscopic data, respectively. All of the isolates were evaluated for their effects on the inhibition of nitric oxide (NO) production in lipopolysaccharide-activated RAW264.7 macrophages and compounds 1 and 8 exhibited inhibitory activity with IC(50) values of 35.80 and 24.41 μM, respectively. 相似文献
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