Antiviral, haemolytic and molluscicidal activities of triterpenoid saponins from Maesa lanceolata: Establishment of structure-activity relationships

Ten saponins isolated from the leaves of Maesa lanceolata were tested for t heir antiviral, haemolytic and molluscicidal activities. The influence of t he substitution pattern of these acylated triterpenoid saponins on their bi ological activities was investigated and structure-activity relationships w ere established. Maesasaponin VI2 (3 beta -O-{[alpha -L-rhamnopyranosyl-(1 --> 2)-beta -D-galactopyranosyl-(1 -->3)]-[beta -D-galactopyranosyl-(1 --> 2)]-beta -D-glucopyranuronyl}-21 beta ,22 alpha -diangeloyloxy-13 beta ,28- epoxyolean-16 alpha ,28 alpha -diol), the most potent molluscicidal compoun d (LC50 0.5 ppm), also showed virucidal and haemolytic activity. In general , 21,22-diacylation appeared to be associated with a virucidal (reduction f actor of the viral titer greater than or equal to 10(3) at 50 mug/ml) and h aemolytic activity (HC50 less than or equal to1 mug/ml).