SELECTIVE INDUCTION OF CELL-DEATH IN CANCER-CELLS BY GALLIC ACID

Gallic acid (3,4,5-trihydroxybenzoic acid) is a naturally occurring pl ant phenol obtained by the hydrolysis of tannins and is known to show some pharmacological activities. In screening anti-cancer agents in tr aditional Chinese medicines, gallic acid,vas found to show cytotoxicit y against all cancer cells that we examined in this study (IC(50)s: 4. 8-13.2 mu g/ml). Gallic acid, however, showed no cytotoxicity against primary cultured rat hepatocytes and macrophages, and lesser cytotoxic ity against fibroblasts and endothelial cells. Cell death in dRLh-84 c ells occurred within 6 h after gallic acid treatment at a concentratio n of more than 20 mu g/ml. A study of structurally related compounds s uggested that the cytotoxicity shown by gallic acid was not a common f eature in phenolic compounds, but was a fairly specific characteristic of gallic acid. That is, three adjacent phenolic hydroxyl groups of g allic acid were responsible for the cytotoxicity, and the carboxyl gro up was not responsible, but seemed to be implicated in distinguishing between normal cells and cancer cells,