Mutagenic and Antimutagenic Activities of Aqueous Extract of Moringa oleifera Leaves

Abstract

Moringa oleifera is a cosmopolitan tree that grows in many tropical countries and useful for its various nutritional and pharmacological applications. In this study, aqueous extract of M. oleifera leaves was evaluated for its mutagenic and antimutagenic activities by Salmonella/microsome mutagenicity assay (Ames test). Mutagenic assay in Salmonella typhimurium (TA 98 and TA 100 as tester strains) with and without metabolic activation showed that 0.2-5 mg/plate of M. oleifera extract did not induce the growth of His+ revertant colonies in both strains, indicating the absence of mutagenicity. Therefore, antimutagenic activities of M. oleifera extract against the standard mutagens, aflatoxin B1 (AFB1) and 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (AF-2) were tested in S. typhimurium TA100 strain. The number of His+ revertants/plate of S. typhimurium after incubation of M. oleifera extract (1-5 mg/plate) with AFB1 (0.1 μg/plate) was not different from positive control, however, 5 mg/plate of the extract exhibited the significant inhibition of the His+ revertant colonies (51.33% Inhibition) when incubated with AF-2 (0.01 μg/plate). It was clear from the present studies that aqueous extract M. oleifera was capable of antimutagenicity through the mechanism in which some active compounds contained might inhibit the mutagen penetration into S. typhimurium cells or neutralize the mutagenic potency prior to nucleus entering, thus protecting the hot-spot region of gene from mutation. Of the results obtained, the further studies will be forward to the investigations including antimutagenicity and cancer chemoprevention in vivo.