A new flavone C-glycoside from clematis rehderiana

Abstract

A new flavone C-glycoside, isovitexin 6-O-E-p-coumarate (1) and two known flavonoid glycosides-quercetin 3-O-β-D-glucuronopyranoside (2) and isoorientin (3)- were isolated from an ethanol extract of aerial parts of Clematis rehderiana. Their structures were determined by spectroscopic methods. The antioxidant effects of the two flavone C-glycosides were evaluated by both the MTT and DPPH assays. Compound 1 showed potent activities against H 2O2-induced impairment in PC12 cells within the concentration range tested, whereas compound 3 scavenged DPPH radical strongly, with an IC50 value of 13.5 μM. © 2010 by the authors.