Antioxidant activities of extract and fractions from Tuber indicum Cooke & Massee

The antioxidant activities of ethanolic crude extract (ECE) and its four different solvent sub-fractions (namely, petroleum ether fraction (PEF), ethyl acetate fraction (EAF), n-butyl alcohol fraction (BAF) and the rest fraction (RF)) from Tuber indicum were investigated using several in vitro antioxidant assays. ECE and four sub-fractions possessed different antioxidant and radical-scavenging activities in different assays. BAF showed the most potent radical-scavenging activity on DPPH radicals, superoxide anion radicals and reducing power, with EC50 values of 1.38, 0.96, 16.0 mg/ml, respectively. EAF exhibited the highest hydroxyl radical-scavenging and ferrous ion chelating activities with EC50 values of 3.31 and 0.70 mg/ml, respectively. The total phenolics (TP) and total flavonoids (TF) were also determined. BAF had the highest TP and TF contents, and the next was EAF. These results showed that the amounts of phenolics and flavonoids were in accordance with higher effectiveness in scavenging radicals and chelating ferrous ions.

Research highlights
► Ethanolic extract and its sub-fractions of Tuber indicum have antioxidant activity.
► The activity of n-butyl alcohol fraction and ethyl acetate fraction is better.
► The antioxidant activity is related to the contents of phenolics and flavonoids.