Inhibitory efect of uprocessed/processed aliums under in vitro/in vivo conditions on carcinogen induced mutagenesis using different assays

Abstract

Three experiments were carried out to assess the antimutagenic potential of garlic or onion This was tested in, in vitro/in vivo models where mutagenicity was induced either with benzo (a) pyrene (BP)/3-methyl-cholanthrene (3MC), using Ames test or the comet assay. Also the effects of cooking processes like boiling/frying on the antimutagenic potential of these alliums were tested by SOS inhibition assay using 4-nitroquinoline-N-oxide (4 NQO) as the mutagen. In the first experiment, onion feeding at 1 and 5% in the diet inhibited the formation and excretion of urinary mutagens in dose dependent manner as indicated by decreased frequency of revertants in strains TA 98 and TA100 in the presence of urine belonging to rats fed onion and exposed to BP or 3MC. In the second experiment using SOS induction assay, both processed or unprocessed garlic exhibited dose dependent inhibition of SOS induction. However with boiled/unboiled onion this was not statistically significant. Studies with DAS also showed a dose dependent inhibition of SOS induction. No significant differences were observed in inhibition of SOS responses with processing of onion/garlic. These results indicate that the antimutagenic principle in garlic is not destroyed on heat treatment during cooking processes. In the third experiment, BP treatment resulted in comet induction (as judged by the comet ratio¬diameter/length) significantly as compared to control, both in liver and kidney tissues (p<0.001). Allium vegetables fed groups showed values similar to control group. As was observed in the peripheral blood lymphocytes, a trend towards recovery from damage was noted both in liver and kidney tissue due to prior allium feeding. All these results show that alliums whether in the processed or unprocessed form can be used in diets to avert toxic effects of environmental carcinogens/genotoxicants and can be potent chemopreventive agents and cancer prevention is far more desirable alternative than treatment by surgery and drugs. The protection could be achieved even by very low intake level of allium in natural form through diet.