Alkaloids from Corydalis saxicola and their anti-hepatitis B virus activity.

Eight protoberberine-type alkaloids and two indole alkaloids were isolated from the MeOH extracts of the herb Corydalis saxicola Bunting (Papaveraceae). Their structures were identified as dehydrocavidine (1), dehydroapocavidine (2), dehydroisoapocavidine (3), berberine (4), dehydroisocorypalmine (5), coptisine (6), tetradehydroscoulerine (7), berbinium (8), 1-formyl-5-methoxy-6-methylindoline (9), and 1-formyl-2-hydroxy-5-methoxy-6-methylindoline (10). Compounds 3, 9, and 10 are new alkaloids. All compounds were tested for anti-HBV activity against the 2.2.15 cell line in vitro. Dehydrocavidine (1), dehydroapocavidine (2), and dehydroisoapocavidine (3) exhibited inhibitory activity against HBsAg and HBeAg, but no cytotoxicity against the 2.2.15 cell line.