COMPARATIVE INVESTIGATION OF TOTAL ANTIOXIDANT AND FREE RADICAL SCAVENGING ACTIVITIES OF TWO ALLIUM SPECIES

ABSTRACTObjective: The main intention of this study was to assess the comparative free radical scavenging and total antioxidant capacities (TAC) of freshAllium sativum (garlic) bulbs and Allium cepa cultivar (green onion) leaves and bulbs for aqueous and methanolic extracts.Methods: The antioxidant ability of the different plant extracts were assessed using TAC method as well as hydrogen peroxide (H2O2) free radicalscavenging method.Results: H2O2 free radical scavenging assay showed that the methanolic extracts of garlic bulbs, green onions leaves, and green onion bulbs produceda maximum percentage scavenging of 89%, 85.4%, and 66.4% respectively at 1000 μg/ml. The methanolic extract of garlic showed the minimumvalue for 50% inhibitory concentration (IC50) of 257.54 μg/ml followed by the aqueous extract of green onion leaves with IC50 of 258.33 μg/ml. TACrevealed that garlic bulbs and green onions leaves exhibited high percentage antioxidant capacity of 91.66% and 91.21% respectively at 1000 μg/ml.The minimum IC50 values for methanolic extracts of garlic and green onion leaves were found to be 64.033 μg/ml and 69.965 μg/ml respectively. TheIC50 value for ascorbic acid was found to be 88.321 μg/ml.Conclusion: Based on this aspect, we propose that this investigation can lead to the establishment of new and more potent drugs from cheaper nativeplants from natural origin since lacunae still remain in scrutinizing the various cultivars of green onions. Further studies are recommended for thein vivo investigations to commercialize their use as a cure to cancer.Keywords: Green onion, Garlic, Total antioxidants capacity, Hydrogen peroxide free radical scavenging assay, Free radicals, Cancer