Abstract: Four triterpenoid saponins, mimengosides A and B and buddlejasaponins I and Ia were isolated from a traditional Tibetan medicinal plant, Oreosolen wattii Hook. f., together with acteoside and 6-hydroxyluteolin-7-O-glucoside. The in vitro spermicidal activities of the four saponins were tested by a modified Sander-Cramer method. Mimengoside A and buddlejasaponin I Showed stronger activity than the positive control NP-9.

Key words: Oreosolen wattii