Mutagenicity and antimutagenicity studies of tannic acid and its related compounds

Tannic acid and its hydrolysed products such as ellagic acid, gallic acid and propyl gallate were tested for mutagenicities using Ames Salmonella tester strains TA98 and TA100. Also, the antimutagenic activities of these compounds against a number of direct mutagens including 2-nitrofluorene (2-NF), 4,4′-dinitro-2-biphenylamine, 1-nitropyrene, 1,3-dinitropyrene, 2-nitro-p-phenylenediamine, 3-nitro-o-phenylenediamine, 4-nitro-o-phenylenediamine were tested. None of these tannic acid compounds was mutagenic. They also failed to show antimutagenic activity towards the tested direct mutagens. However, tannic acid at non-growth inhibitory concentrations reduced the revertant numbers of TA98 in the presence of S9 mix when benzidine, 3,3′-4,4′-tetraminobiphenyl, 4-aminobiphenyl, and N,N-N′,N′-tetramethylbenzidine were used as the mutagens. These results suggest that tannic acid, but not its hydrolytic products, affects the metabolic activation of these mutagens.