Decontamination of Withania somnifera by Gamma Irradiation and its Effect on Antioxidant Activities

Abstract

The current investigation was carried out to study the effect of gamma irradiations on decontamination of Withania somnifera and its antioxidant activity. W. somnifera dry roots were packed and irradiated at doses of 1？10 kGy following the storage at 4C within a week. At the dose of 10 kGy, the microbial contamination was lowered below detection level. Glycowithanolides are known for antioxidant components present in W. somnifera. The antioxidant activity of W. somnifera extract was investigated by measuring 1,1-diphenyl- 2-picrylhydrazyl, hydroxyl and superoxide radical-scavenging activities. These activities were increased in samples extracted from the irradiated roots at 10 kGy. The extraction yield of the glycowithanolides was considered as one of the reasons for the increase of antioxidant activities of the extract.