Antimutagenic effect of fruit and vegetable aqueous extracts against N-nitrosamines evaluated by the Ames test

The inhibitory effect of nine fruit and vegetable aqueous extracts against the mutagenicity of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosodibutylamine (NDBA), and N-nitrosopiperidine (NPIP) was evaluated by means of the Ames test. Onion extract (500 mu g/plate) showed the greatest inhibitory effect (60%) against NDMA, and the mutagenicity of NPYR was inhibited markedly (54%) by apple extract (50 mu g/plate). The antimutagenic effect of carrot extract (250 mu g/plate) was remarkable (49%) against NDBA, and the mutagenicity of NPIP was also strongly inhibited (65 and 50%) by garlic and kiwi extracts (2000 mu g/plate), respectively. Vegetable and fruit extracts that exhibited an antimutagenic effect in decreasing order against NDMA and NPYR were as follows: onion > licorice > kiwi = apple, carrot > garlic > pineapple > broccoli; and apple > broccoli > kiwi > onion = pineapple, respectively. Decreasing orders against NDBA and NPIP were, respectively, carrot > garlic > broccoli > onion > kiwi and garlic > kiwi > broccoli > green pepper > pineapple > carrot > onion = apple.