A cytotoxic sesquiterpene alkaloid from the South China Sea gorgonian Subergorgia suberosa

A new sesquiterpene alkaloid, 6-(9'-purine-6',8'-diolyl)-2 beta-suberosanone (1), together with three known sesquiterpenes, suberosenol A (2), subergorgic acid (3), and subergorgiol (4), was isolated from the EtOH/ CH2Cl2 extracts of the South China Sea gorgonian Subergorgia suberosa. The structure of 1 was determined through spectroscopic methods. Compound 1 showed moderate cytotoxicity against the human breast carcinoma MDA-MB-231 cell line with an IC50 of 8.87 mu g/mL.