Modification of apoptosis-inducing activity of gallic acid by saliva

Gallic acid, a structural unit of tannin, induced apoptotic cell death, cha racterized by nuclear condensation and caspase activation in human oral tum or cell lines (HSC-2, HSG). Agarose gel electrophoresis demonstrated that g allic acid produced large DNA fragments in these cells, as well as in T-cel l leukemia (MOLT-4) and erythroleukemia (K-562) cells, whereas it induced i nternucleosomal DNA fragmentation in human myelogenous leukemic cell lines (HL-60, ML-1, U-937, THP-1). This indicates that induction of internucleoso mal DNA fragmentation or production of large DNA fragments depends on both target cells and inducers. Addition of total saliva dose-dependently reduce d the cytotoxicity induction by gallic acid. These data suggested that the biological action of gallic acid might be modified by physiological fluids.