Abstract:
The possible modulating effect of some mushrooms namely: Agaricus bisporus (button, เห็ดกระดุม ), Lentinus edodes (Shiitake, เห็ดหอม ), Pleurotus ostreatus (Oyster เห็ดนางรม), and P.abalonus (Abalone เห็ดเป๋าฮื้อ), in 3 conditions (fresh, blanching and fermention) on mutagenicity induced by urethane in somatic mutation and recombination test in Drosophila melanogaster was investigated. Three day old trans-heterozygous larvae, obtained by mating virgin females of Oregon wing flare hair strain and males of multiple wing hair strain on standard medium, were transferred to sample medium and experimental medium (samples extracts plus urethane 20 mM) for the simultaneous feeding study. The virgin females and males designated in the pre-feeding study were mated on an experimental medium until the larvae were three-days old. Then they were transferred to positive medium and experimental medium as type II or I experiment respectively until they became adult flies. The round wings of all surviving flies were analyzed for the occurrence of mutant spots. It was found that all extracts were not toxic or mutagenic in both studies. In simultaneously feeding study. only fresh/fermented shiitake and fresh/ fermented oyster mushroom reduced number of induced wing spots while the other extracts showed no effect. In contrast, fresh and blanched button mushrooms increased number of induced wing spots. It was proposed that some compounds obtained from biochemical changes during fermentation might activate glutathione S-transferase activity or decrease the activity of cytochrome P-450 or lactic acid bacteria existed during fermentation process could retard the activity of any toxicants. Fermented mushroom extracts need to be clarified in further studies. Pre-feeding of three-day old larvae with fresh button mushroom in type II experiments and fresh/blanched oyster mushroom both types I and II experiment increased the frequency of mutant spots. The possible mechanism might be the stimulation of cytochrome P-450 or inhibition of detoxification enzymes. Interestingly. the antimutagenicity of all fermented mushrooms was shown in pre-feeding study. It was proposed that the extracts might activate glutathione-S-transferase activity or decrease the activity of cytochrome P-450 enzymes.
