Portal de Periódicos da CAPES

Inhibitory effects of new types of biflavonoid-related polyphenols; lophirone A and lophiraic acid, on some tumor promoter-induced biological responses in vitro and in vivo

1991; Elsevier BV; Volume: 58; Issue: 1-2 Linguagem: Inglês

10.1016/0304-3835(91)90030-l

1872-7980

Akira Murakami, Hiroaki Ohigashi, Mitsuo Jisaka, Mitsuru Hirota, Ryozo Irie, K. Koshimizu,

Bioactive Compounds and Antitumor Agents

Lophirone A, isolated as a new type of biflavonoid-related inhibitor of Epstein-Barr virus (EBV) activation, was tested for further inhibitory properties against tumor promotion by short-term systems. Lophirone A (200 μg) significantly inhibited inflammation of mouse ear (inhibitory effect (IE) = 70%) by 12-O-hexadecanoyl-16-hydroxyphorbol-13-acetate (HHPA, 2 μg). It also inhibited both Ca2+- and phospholipid-dependent protein kinase C (PKC) activation by 12-O-tetradecanoylphorbol-13-acetate (TPA, IC50 = 50 μM). Application of lophirone A (160 nmol) reduced the number of tumors per mouse (IE = 85%) in an initiation-promotion experiment using dimethylbenz[a]anthracene (DMBA, 0.19 μmol) and TPA (1.6 nmol) on ICR mouse skin. Lophiraic acid, a related polyphenol, was negative in all of the short-term tests. An important chemical factor which may reduce the activities of flavonoid class of inhibitors for tumor promotion was indicated.