InVitro Antioxidant and Free Radical Scavenging Activity of Withania Somnifera Root

Withania somnifera of the family Solanaceae has been considered as an important herb in the traditional Ayurvedic and in the indigenous medical system in Bangladesh for its use in the prevention of different central nervous system (CNS) disorders, especially in the conditions of stress and neurodegenerative diseases. Five different extracts of Withania somnifera root were scrutinized to unfold the antioxidant and free radical scavenging activity. In the present study, the free radical scavenging potential of five extracts of the root of Withania somnifera was assessed by measuring its capability for scavenging 2, 2-diphenyl-1-picrylhydrazyl (DPPH.) radical, hydrogen peroxide radical, nitric oxide radicals (NO.), as well as its ability in Reducing power capacity assessment, Cupric Reducing Antioxidant Capacity, using appropriate assay systems compared to natural and synthetic antioxidants. Total antioxidant capacity and phenolic, flavonoid contents were determined spectrophotometrically. In-vitro antioxidant activity of the extracts of Withania somnifera was performed and Ethanol and methanol extract of Withania somnifera showed noticeable effect in the DPPH scavenging assay, reducing power capacity, cupric reducing antioxidant capacity and nitric oxide scavenging assay. In case of total phenolic content and total antioxidant capacity methanol and ethanol extract of Withania somnifera showed significant activity. A linear correlation appeared between the total antioxidant capacity and the total phenolics contents of the extracts with good correlation coefficient (R = 0.891). N-hexane and petroleum ether extract showed least activity in all the measures. Our study demonstrated that the five different extracts of Withania somnifera root showed different level of antioxidant activity and is a potential source of antioxidants and thus could prevent many radical related diseases.