Antimutagenic activity of carotenoids in green peppers against some nitroarenes

In Mexico, as well as in Central and South American countries, the consumption of peppers ( Capsicum annuum) has been tradition for thousands of years; the per capita dietary intake of peppers is about 40 g/day. Peppers are an important source of β-carotene and vitamin A, which have antimutagenic and/or anticarcinogenic properties. In the present study, Salmonella typhimurium tester strain YG1024 in the plate-incorporation test was used to examine the antimutagenicity of carotenoids extracted from five different types of Capsicum spp. (`Chilaca', `Poblano', `Serrano', `Jalapeño' and `Pimiento') which were chosen, based on their consumption and availability on the local market. Extracts from these peppers were tested against 1-nitropyrene (1-NP); 1,6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene (1,8-DNP) mutagenicity. Dose–response mutagenicity curves of 1-NP; 1,6-DNP and 1,8-DNP were obtained. For the antimutagenicity studies, doses of 0.05 μg/plate, 0.20 ng/plate and 0.06 ng/plate for 1-NP, 1,6-DNP and 1,8-DNP respectively were chosen, and the number of net revertants/plate were 1008 for 1-NP, 512 for 1,6-DNP, and 712 for 1,8-DNP. Trans-β-carotene and the extracts were not toxic to the bacteria at the concentrations tested. The extracts obtained from the peppers showed more inhibition than pure trans-β-carotene on 1-NP; 1,6-DNP and 1,8-DNP mutagenicity. Chilaca pepper extract required 0.36 g (34 nmol expressed as trans-β-carotene equivalents) of fresh pepper to inhibit 94% on 1-NP mutagenicity, 78% on 1,6-DNP mutagenicity and 84% on 1,8-DNP mutagenicity. Bell pepper (`Pimiento') extract required 1.53 g (50 nmol expressed as trans-β-carotene) to obtain 87%, 79% and 73% inhibition on 1-NP; 1,6-DNP and 1,8-DNP mutagenicity respectively. Since pure β-carotene inhibited only approximately 50% the mutagenicity of nitroarenes, these results suggest that each one of the pepper extracts have more than one antimutagenic compound (e.g., β-carotene and xanthophylls) and those functional nutrients apparently have a synergistic effect.