Antibacterial Activity of Acylated Flavonol Glycoside from Waltheria indica

Abstract

A rare acylated flavonol glycoside, kaempferol 3-O-β-D-(6''-E-p-coumaryl)-glucopyranoside (1), together with five known flavonoids, quercetin 3-O-glucopyaranoside (2), kaempferol-3- O-α-L- rhamnoside (3), kaempferol-3-O-β-D-glucopyranoside (4), quercetin (5) and kaempferol (6) were isolated from the whole plant of Waltheria indica. The structures of these compounds were elucidated by FABMS, UV, ¹D and ²D NMR spectroscopy including COSY, HSQC and HMBC experiments and acid hydrolytic and saponification studies. Compound 1 was isolated for the first time from the family Sterculiaceae. These compounds were screened for antibacterial activity against Staphylococcus aureus and Escherichia coli.