Peroxynitrite is a powerful oxidant produced by macrophages and neutrophils. We have investigaed the reaction of peroxynitrite with some carotenoids such as β-carotene, astaxanthin and lutein in vitro. In the present study, reactions of peroxynitrite with capsanthin and fucoxanthin were studied. 14'-s-cia-15'-nitrocapsanthin (1), 12-nitro-capsanthin (2), 14-s-cis-15-nitrofucoxanthin (3), and 11-cis-11-nitro-fucoxanthin (4) were obtained by these reactions. These results indicated that carotenoids could take up peroxynitirite through the formation of nitrocarotenoids and/or oxazine carotenoids (in the case of lutein). These reactions would probably be occurred in vivo and suggest that carotenoids might contribute to the prevention of peroxynitrite induced disease.
