Biol Pharm Bull. 1997 Sep; 20(9): 1017-9.

Immunosuppressive effects of gallic acid and chebulagic acid on CTL-mediated cytotoxicity.

Hamada S, Kataoka T, Woo JT, Yamada A, Yoshida T, Nishimura T, Otake N, Nagai K.

Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan.

Gallic acid (GA) and chebulagic acid (CA) were isolated from the extract of a herbal medicine, kashi (myrobalans: the fruit of Terminalia chebula) as active principles that blocked the cytotoxic T lymphocyte (CTL)-mediated cytotoxicity. GA and CA inhibited the killing activity of CD8+ CTL clone at IC50 values of 30 microM and 50 microM, respectively. Granule exocytosis in response to anti-CD3 stimulation was also blocked by GA and CA at the equivalent concentrations.