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 12-0-tetradecanoylphorbol-13-acetate-induced Epstein-Barr virus activation. The 1C50 value of zerumbone (0.14 mu-m) 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 (IC50100 mu-M), while 8-hydroxy-alpha-humulune was markedly active (IC50= 0.95 mu-M)