Antioxidant activity of toyserkani variety of walnut husk and comparison of its antiradical activity with synthetic antioxidants

The aim of this study was extraction of phenolic compounds from Touyserkani variety of walnut husks with two extraction methods (traditional method and with microwave assisted extraction (MAE)) and with solvents (methanol 80%, ethanol 50% and water) in different times. Total Phenolic contents were determined by Folin Ciocaltue assay. Then the antioxidant activity of extracts was assessed through reducing power assay, DPPH radical-scavenging activity and total antioxidant activity. The results showed boiling water in traditional method and methanol 80% in microwave assisted extraction were optimum solvents. Lowest IC50 in DPPH radical-scavenging activity in traditional method was water extract and it in MAE was ethanolic extract. Finally, effects of methanol extract in retarding the soy oil oxidation were examined. Methanol extract with the concentration of 1000 ppm could control oxidation. Result of this study showed that walnut husk is a potential source of natural antioxidants.