Jaspiferins C-F, four new isomalabaricane-type triterpenoids from the South China Sea sponge Jaspisstellifera

A chemical investigation of marine sponge Jaspis stellifera, collected from the South China Sea, led to the isolation of four new isomalabaricane-type triterpenoids, jaspiferins C-F (1-4). The structures of those compounds were elucidated by extensive spectroscopic methods. Jaspiferin C (1), which has the six-membered carbon ring at the side chain, was discovered for the first time from the isomalabaricane-type triterpenoids. The hypothesis of a biogenetic pathway to generate jaspiferin C (1) was depicted.