Antiviral activity of lignans and their glycosides from Justicia procumbens

Ten antiviral lignans, seven known (justicidins A, B, C and D, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate) and three new compounds, justicidinosides A (justicidin C 6'-O-glucoside), B (justicidin A 6'-O-glucoside) and C (justicidin B 6'-O-glucoside), were isolated from a methanolic extract of the aerial parts of Justicia procumbens var. leucantha. Justicidins A and B, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate showed strong antiviral activity (the MIC were less than 0.25 mu g ml(-1), respectively) against vesicular stomatitis virus and low cytotoxicity (the MTC were larger than 31 mu g ml(-1), respectively) against cultured rabbit lung cells (RL-33).