Comparative Study of Natural and Synthetic Food Additive Dye Amaranth through Photochemical Reactions

Food additive Amaranth dye (1) was isolated from amaranth plant (Amaranthaceae). Natural and synthetic ones were subjected to photo-catalyzed reaction using titanium dioxide (in micro and nano particles size) as heterogeneous singlet oxygen sensitizer. or Rose Bengal as homogeneous singlet oxygen sensitizer under irradiation of mercury lamp. Synthetic Amaranth dye (1) gave disodium 3, 4-dioxo-3, 4-dihydro-naphthalene-2, 7-disulfonate (2), disodium 3, 4-dihydroxy-3, 4-dihydro-naphthalene-2, 7-disulfonate (3) and sodium 4-hydroxy-naphthalene-1-sulfonate (4) in the case of TiO2. Whereas photo-oxidation of 1 with Rose Bengal, which gave 2 and 4. Toxicological examination of the photo-degraded product 3 on DNA was investigated showing a high degree of DNA degradation. Natural Amaranth dye (1) showed high stability towards this reaction, only decolorization has been done to it.