Isolation and structural identification of C-glycosyl flavonoids from the leaves of Ohwia caudata(Thunberg)H.Ohashi
Objective The chemical constituent′s investigation of Ohwia caudata(Thunberg)H.Ohashi leaves was carried out to enrich its material basis.Methods The dried leaves of O.caudata were extracted by heating reflux to obtain 70%EtOH extraction.Then,the extraction was separated and purified by various chromatographic methods to gain compounds,whose structures were identified by using NMR and mass spectra mainly.Results Fifteen C-glycosyl flavonoids named as isovitexin(1),vitexin(2),6,8-di-C-β-D-glucopyranosylapigenin(3),isosaponarin(4),isovitexin-2″-O-rhamnoside(5),swertisin(6),isoswertisin(7),2″-O-rhamnosylswertisin(8),2″-α-rhamnopyranosyl-7-O-methylvitexin(9),luteolin 6-C-β-glucopyranoside(10),luteolin 8-C-β-glucopyranoside(11),isoorientin-2″-O-rhamnoside(12),swertiajaponin(13),2″-O-rhamnopyranosyl-7-O-methylisoorientin(14),and isoscoparin-7-O-glucoside(15)were obtained from the 70%ethanol extract of O.caudata leaves.Conclusion Among them,compounds 4,5,7,11-15 are gained from Ohwia genus for the first time.
the leaves of Ohwia caudata(Thunberg)H.Ohashi.C-glycosyl flavonoidsstructural identificationrestricted rotational isomerism
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