Sesquiterpenes from the soft coral Paralemnalia thyrsoides and their biogenetic correlation

Terpenoids are the important secondary metabolites of soft coral. In the investigation of soft corals collected from South China Sea, we have found many cembranoid diterpenes with bioactivity and two rare unique biscembranoid tetraterpenes, i.e. methyl sartortuoate and methyl isosartortuoate. We have suggested a plausible biogenesis pathway for these two tetraterpenoids in the soft coral Sarcophyton tortuosum.Recently, B. F. Bowden et al. obtained one more tetraterpenoid with the similar structure from the same species Australian soft coral. Besides, they isolated one of the probably