Triterpene saponins of ursane and oleane type isolated from the involucral bracts of Cynara cardunculus L. (Asteraceae) were investigated in in vitro assays for their activity on the complement system. The anticomplementary activity of bidesmosidic saponins on the classical pathway activation of the complement was higher than the activity of monodesmosidic saponins, but esterification of the carboxylic group of glucuronic acid in the sugar residue resulted in a significant decrease in anticomplementary activity.

        Key words: Cynara cardunculus L. – Asteraceae – saponins – triterpenes – anticomplementary activity