Effect of Preparation and Temperature Treatments on Antimutagenicity against Urethane in Drosophila melanogaster and Antioxidant Activity of Three Allium Members

Abstract

We investigated whether the effects of preparations (pounding or chopping) and heat treatments (100oC or 200oC) modified the antimutagenicity of garlic, shallot and onion against urethane induced somatic mutation and recombination in Drosophila melanogaster. Three-day old transheterozygous larvae (mwh flr+/mwh TM3) were transferred to an experimental medium (containing a treated sample) that had 20 mM urethane. The wings of surviving flies were analyzed for occurrence of mutant spots. The results showed that all treated samples still had both antimutagenicity and antioxidant activity (determined using DPPH scavenging capacity and ferric reducing antioxidant power) and phenolic compounds (determined using Folin-Ciocalteu reagent). Treating garlic with 100oC and 200oC before preparations slightly reduced its antimutagenicity. It was proposed that heat treatment slightly destroyed alliinase; thus, the formation of allicins and other organosulfur compounds (commonly turn to be alkylsulfides or allicin derivatives which are the inducers of phase 2 detoxification system) from alliin was reduced. On the other hand, pounding and chopping before applying heat treatments reduced the antimutagenicity of shallot and onion while heat treatment had lower effect if the samples still be a bulb or cut into large piece. It was proposed that the formation of sulfur containing compounds derived from isoalliin by alliinase during pounding and chopping were very labile to atmosphere during the 10 min standing at room temperature. Thus the effect of preparation and heat treatment unequally influenced on the antimutagenicity and the antioxidant activity including total phenolic compounds of three Allium members.