Identification of zerumbone in Zingiber zerumbet Smith as a potent inhibitor of 12-O-tetradecanoylphorbol-13-acetate-induced Epstein-Barr virus activation.

Zerumbone was isolated from the rhizomes of Zingiber zerumbet Smith as a potent inhibitor of tumor promoter 12-O-tetradecanoylphorbol-13-acetate-induced Epstein-Barr virus activation. The IC50 value of zerumbone (0.14 microM) is noticeably lower than those of the anti-tumor promoters we have hitherto obtained. Interestingly, alpha-humulene lacking the carbonyl group at the 8-position in zerumbone was inactive (IC50 > 100 microM), while 8-hydroxy-alpha-humulune was markedly active (IC50 = 0.95 microM).