Flavonolignans from Hyparrhenia hirta

Leaves of Hyparrhenia hirta yielded the rare diastereoisomeric flavonolignans tricin 4'-O-(erythro-beta-guaiacylglyceryl) ether and tricin 4'-O-(threo-beta-guaiacylglyceryl) ether together with their 7-O-glucosides, which are the first flavonolignan glycosides to be isolated as natural products. A complete set of H-1 and C-13 NMR resonance assignments obtained for both flavonolignan aglycones indicates the need for revision of data published previously for these compounds and for a reassessment of their original stereochemical designation. (C) 2002 Elsevier Science Ltd. All rights reserved.