In vitro anti-complementary activity of flavonoids from olive (Olea europaea L.) leaves.

From extracts of olive (Olea europaea L., Oleaceae) leaves showing anti-complementary activity, the flavonoids apigenin, apigenin-4'-O-rhamnosylglucoside, apigenin-7-O-glucoside, luteolin, luteolin-4'-O-glucoside, luteolin-7-O-glucoside, chrysoeriol, chrysoeriol-7-O-glucoside and quercetin-3-O-rhamnoside were isolated. Major isolated constituents strongly inhibited the classical pathway of the complement system.