Study on Antioxidant Activity of Thermal Treatment Yam (Dioscorea batatas DECNE.) by n-Butanol and Ethyl Acetate Extracts

In Korea, yam with thermal treatment is widely used to produce tea and beverage, which appeals to all age groups. To better understand the antioxidative activity of thermal treatment yam (Dioscorea batatas DECNE.), n-butanol and ethyl acetate extracts were evaluated with different antioxidant testing system. Their antioxidant activities, including ABTS[2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power as well as total phenol contents were assessed in vitro. Results showed ethyl acetate extract (51.63±2.51 mg CAE/g) possessed similar total phenol content compared with n-butanol extract (53.93±1.00 mg CAE/g). Ethyl acetate extract also exhibited similarly stronger antioxidant activity compared with n-butanol extract apart from ABTS radical scavenging activity assay.