Effect on Urethane Induced Mutagenicity in Drosophila melanogaster of Different Germinated Unpolished Rice and the Thai Desserts Made from Them

Abstract

Four kinds of rice (Oryza sativa L.), namely polished Jasmine rice, germinated unpolished Jasmine rice and germinated unpolished red Jasmine rice, germinated unpolished Homnil rice were proved to have antioxidant activity and phenolic compounds. Each type of rice was blended and used to make rice crispy, dried rice ball and steamed banana cake. The desserts were evaluated for their modulating effect on urethane induced wing spots in Drosophila melanogaster. In the evaluation, three-day-old trans-heterozygous larvae (mwh flr⁺/mwh TM3) were transferred to the Drosophila medium that each dessert was substituted for corn flour (used for the mutagenicity evaluation of each sample) and the Drosophila medium that each dessert and 20 mM urethane were substituted for corn flour and water (used for antimutagenicity evaluation of each sample). The wings of the surviving flies were analyzed for the occurrence of mutant spots. Most of the samples were non-mutagenic. Although the Drosophila medium prepared from each germinated unpolished rice meal increased the mutagenicity of urethane (possibly be due to the high content of polyunsaturated fatty acids that might lead to the generation of free radicals in test organism) almost all of the desserts made from the three type of geminated unpolished rice reduced the mutagenicity of urethane at various degrees. It was suspected that some components, besides the rice meal in the deserts, might be the modulators of urethane biotransformation.