In continuation of work on Solanum incanum a new steroidal alkaloid glycoside has been isolated from the fresh berries, which is named incanumine, and characterized as O(3)-[beta-D-xylopyranosyl-(1----3glu)-[beta-D-xylopyranosyl-(1--- -4rha)- alpha-L-rhamnopyranosyl-(1----4)]-beta-D-glucopyranosyl)-solasodine++ +. Solamargine, solasodine, ursolic acid, and ursolic acid derivatives (3-O-palmitoyl ursolic acid, 3-O-crotonyl ursolic acid, 3-O-propionyl ursolic acid) exhibited significant cytotoxic effects against human PLC/PRF/5 cells in vitro. Esterification of ursolic acid with aliphatic acids clearly enhanced the cytotoxic effects against human PLC/PRF/5 cells in vitro.