Tridemethylisovelleral, a potent cytotoxic agent.

The synthesis and in vitro cytotoxicity toward various tumor cell lines of (+/-)-tridemethylisovelleral, an analogue of the bioactive fungal sesquiterpene (+)-isovelleral retaining the bicyclo[4,1,0]hept-2-en-1,2-dicarbaldehyde system but lacking the three methyl groups, is reported. The cytotoxicity of tridemethylisovelleral toward several tumor cell lines was found to be comparable with those of established antitumor drugs, and significantly higher than that of isovelleral.