- Four new norlignan glycoside isomers from the twigs of Cephalotaxus oliveri Mast.
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Four novel isomers of norlignan glycoside were isolated from Cephalotaxus oliveri Mast. Their structures were elucidated as 3S-4″-O-β-D-glucopyranosylnyasol 1, 3S-4′-O-β-D-glucopyranosylnyasol 2, 3S-4″-O-β-D-glucopyranosylhinokiresinol 3, 3S-4′-O-β-D-gluc
- Meng, Fan-Cheng,Liu, Hui,Huang, Xiao-Jun,Chang, Yu,Ren, Dai,Lin, Li-Gen,Zeng, Qing-Qian,Zhang, Qing-Wen
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- Subunit composition of hinokiresinol synthase controls enantiomeric selectivity in hinokiresinol formation
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Asparagus officinalis hinokiresinol synthase (HRS) is composed of two subunits, HRSα and HRSβ. Individually, each subunit forms (E)-hinokiresinol (EHR) from 4-coumaryl 4-coumarate, whereas a mixture of both subunits forms (Z)-hinokiresinol (ZHR) from the same substrate. In this study, we analyzed the enantiomeric compositions of ZHR and EHR formed after incubation of 4-coumaryl 4-coumarate with recombinant subunit proteins, recHRSα and/or recHRSβ, and with naturally occurring A. officinalis ZHR. The enantiomeric composition of ZHR formed by the mixture of recHRSα and recHRSβ was (+)-100% enantiomer excess (e.e.), identical to that of A. officinalis ZHR. In contrast, the enantiomeric compositions of EHR formed by recHRSα and recHRSβ, individually, were (-)-20.6 and (-)-9.0% e.e., respectively. These results clearly demonstrate that the subunit composition of A. officinalis HRS controls not only cis/trans isomerism but also enantioselectivity in hinokiresinol formation. The Royal Society of Chemistry.
- Yamamura, Masaomi,Suzuki, Shiro,Hattori, Takefumi,Umezawa, Toshiaki
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experimental part
p. 1106 - 1110
(2010/06/20)
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- Structure and absolute configuration of nyasol and hinokiresinol via synthesis and vibrational circular dichroism spectroscopy
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The absolute configuration of the norlignan (+)-nyasol was determined to be S by comparison of the experimental vibrational circular dichroism data with first-principle calculations taking into account the eight lowest energy conformations. The established absolute configuration of (+)-nyasol enables establishment of the absolute configuration of (-)-hinokiresinol, which is concluded to be S. A total synthesis and resolution of hinokiresinol has been performed to resolve the conflicting reports of the coupling constant of the vinylic protons of the disubstituted double bond in this molecule. Racemic hinokiresinol was resolved. Both enantiomers possess the same antiplasmodial activity.
- Lassen, Peter R.,Skytte, Dorthe Mondrup,Hemmingsen, Lars,Nielsen, Simon Feldbaek,Freedman, Teresa B.,Nafie, Laurence A.,Christensen, S. Brogger
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p. 1603 - 1609
(2008/09/17)
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