Hydroxyl radical scavenging activity was assayed by the method of of Siddhuraju and Becker (2007). Fresh peel tissue (2.0 g) from ten fingers withdrawn randomly from each treatment was mixed with 20 mL methanol and then centrifuged at 10,000 × g for 15 min. The collected supernatant (1 mL) was mixed with 1 mL reaction buffer containing 100 μM ferric chloride, 104 μM EDTA, 2.5 mM H2O2, 2.5 mM 2-deoxyribose and 100 μM ascorbic acid. The reaction mixture was incubated for 1 h at 37 °C. A solution of thibabituric acid (TBA) in 1 mL (0.5%; w/v) of 25 mM NaOH solution and 1 mL 2.8% (w/v) trichloroacetic acid (TCA) was added. The mixture was heated for 30 min at 80 °C and then cooled rapidly. The absorbance was measured at 532 nm with a spectrophotometer. The methanol instead of the sample was used as the control. The hydroxyl radical scavenging activity (%) was calculated as (1 − absorbance of sample/absorbance of control) × 100.