Acylated flavonol pentaglycosides from Baphia nitida leaves

Two new acylated flavonol pentaglycosides were isolated from the butanolic extract of Baphia nitida leaves by Sephadex LH-20 and preparative HPLC. Structural elucidation of kaempferol 3-O-beta-D-xylopyranosyl(1 -> 3)-(4-O-E-p-coumaroyl-alpha-L-rhamnopyranosyl(1 -> 2))[beta-D-glucopyranosyl(1 -> 6)]-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (1) and kaempferol 3-O-beta-D-xylopyranosyl(1 -> 3)-(4-O-Z-p-coumaroyl-alpha-L-rhamnopyranosyl(1 -> 2))[beta-D-glucopyranosyl(1 -> 6)]-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (2) was achieved using UV, NMR, and mass spectrometry, indicating the presence of trans or cis isomers of p-coumaric acid moiety in these novel structures. The antioxidant activity of the two compounds was assessed in the peroxynitrite assay. (C) 2010 Phytochemical Society of Europe. Published by Elsevier B. V. All rights reserved.