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', 'Jalapeno' 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. Copyright (C) 1998 Elsevier Science B.V.