The chemical study of two sponges of the genus Dysidea collected in the Gulf of California has led to the isolation of the new merosesquiterpenes 20-O-acetyl-21-hydroxy-ent-isozonarol (2), 20-O-acetylneoavarol (3), ent-yahazunol (4), and dysienone (5), together with the known compounds 1 and 6-9. The structures of the new metabolites have been established by spectroscopic techniques. The absolute configuration of compounds 5 and 6 has been investigated by application of a procedure developed by Riguera et al. Compounds 2 and 5 showed cytotoxic activity against three human tumor cell lines.

Further research on the constituents of the sponge Axinyssa isabela collected in the Gulf of California has led to the isolation of nine new sesquiterpenes, the eudesmanes axinisothiocyanates M and N (1, 2), the bisabolane axinythiocyanate A (3), and the aristolane derivatives axinysones A-E (4-8) and axinynitrile A (9), together with four known sesquiterpenoids (10-13). The structures of the new metabolites have been established by spectroscopic techniques.The absolute configuration of axinysones A (4) and B (5) has been assigned after esterification with (R)- and (S)-MPA acids. In addition, the unusual nitrile-containing sesquiterpene 9 has been synthesized from (+)-aristolone (14). The cytotoxic activity of the compounds isolated has been tested against three human tumor cell lines.