Porritoxins, metabolites of Alternaria porri, as anti-tumor-promoting active compounds.
To search for possible cancer chemopreventive agents from natural sources, we performed primary screening of metabolites of Alternaria porri by examining their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. The ethyl acetate extract of A. porri showed the inhibitory effect on EBV-EA activation. Three porritoxins (1-3) were obtained as inhibitory active compounds for EBV-EA from ethyl acetate extract. 6-(3',3'-Dimethylallyloxy)-4-methoxy-5-methylphthalide (2) showed the strongest activity among them. Inhibitory effect of porritoxin (1) and (2) was superior to that of beta-carotene, a well-known anti-tumor promoter. Furthermore, the structure-activity correlation of porritoxins and their related compounds were discussed.
Horiuchi
Masayuki
M
Research Institute for Production Development, Sakyo-ku, Kyoto 606-0805, Japan. masayuki-h@oct.zaq.ne.jp
Tokuda
Harukuni
H
Ohnishi
Keiichiro
K
Yamashita
Masakazu
M
Nishino
Hoyoku
H
Maoka
Takashi
T
D000528:Alternaria / Q000737:chemistry*; D000956:Antigens, Viral; D000970:Antineoplastic Agents / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology*; D054833:Isoindoles; D015394:Molecular Structure; D013329:Structure-Activity Relationship
D000956:Antigens, Viral; D000970:Antineoplastic Agents; C033305:Epstein-Barr virus early antigen; D007211:Indoles; D054833:Isoindoles; C466610:porritoxin