ABSTRACT
Objective:To determine antioxidant activity and phytochemical content from various tubers extracts of sweet potato (Ipomoea batatas) and to explore the correlation of phytochemical content with their antioxidant activities.Methods:Antioxidant activities were tested using DPPH and FRAP assays.Total phenolic was calculated by Folin-Cioealteu reagent,flavonoid content by Chang's method and correlation with their antioxidant activities were analyzed by Pearson's method.Results:PO2 showed highest antioxidant activity,which had the lowest IC50 DPPH (10.54 μg/mL) and the lowest EC5o FRAP (11.14 μg/mL).PO2 showed the highest total phenolic (11.91 g GAE/100 g) and total flavonoid content (17.83 g QE/100 g).There were significantly negative correlation between total phenolic content and flavonoid content in sample PO with their IC5o DPPH and EC5o FRAP.IC50 DPPH of sample PP and PO showed significantly positive correlation with their EC5o FRAP.Conclusions:Result of DPPH method shows that all different ethyl acetate and ethanolic tubers extracts of four varieties of sweet potato are classified as strong and very strong antioxidant.Result of DPPH and FRAP methods indicates that phenolic and flavonoid compounds in sample PO contributes together to antioxidant activities.Antioxidant activities of sample PP and PO by DPPH method are linear to FRAP method.