Flavone C-glycosides from Lychnis senno and their antioxidative activity.

A new flavone C-glycoside, 5-O-acetyl-2"-alpha-rhamnopyranosylisovitexin (1), was isolated from the aerial parts of Lychnis senno Siebold et Zucc. (Family Caryophyllaceae), along with 2"-alpha-rhamnopyranosylisovitexin (2), 2"-a-rhamnopyranosylisoorientin (3) and isoorientin 3'-mehyl ether (4). All these compounds were isolated for the first time from L. senno and their antioxidative activity was analyzed by the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical-scavenging method. Compound 3 showed moderate antioxidative activity.