Cucurbitane triterpenoids from Momordica charantia and their cytoprotective activity in tert-butyl hydroperoxide-induced hepatotoxicity of HepG2 cells.

Two novel pentanorcucurbitane triterpenes, 22-hydroxy-23,24,25,26,27-pentanorcucurbit-5-en-3-one (1) and 3,7-dioxo-23,24,25,26,27-pentanorcucurbit-5-en-22-oic acid (2) together with a new trinorcucurbitane triterpene, 25,26,27-trinorcucurbit-5-ene-3,7,23-trione (3) were isolated from the methyl alcohol extract of the stems of Momordica charantia. The structures of the new compounds were elucidated by spectroscopic methods. Compounds 2 and 3 showed potent cytoprotective activity in tert-butyl hydroperoxide (t-BHP)-induced hepatotoxicity of HepG2 cells.