*2.6. Antioxidant Activity*

The antioxidant activity of the extracts was estimated by the reduction of free radical DPPH (2,2-diphenyl-1-picrylhydrazyl) method, as described by Oke et al. [23] with minor modifications. The methanol extract (100 μL) was mixed with 5 mL of 0.004% methanol solution of DPPH radical. The reaction mixture was vigorously shaken, then incubated for 30 min in the dark at room

temperature. The absorbance was read against a blank (methanol) at 517 nm using a Shimadzu UV-1201 spectrophotometer, and the percentage of antioxidant activity was calculated as Equation (3).

$$\text{AA} = \left[ (\text{A}\_{\text{B}} - \text{A}\_{\text{S}}) / \text{A}\_{\text{B}} \right] \times 100 \tag{3}$$

where, AA is antioxidant activity expressed as a percentage, AB is absorbance of the blank (containing reaction mixture without sample extract) and AS is absorbance of the reaction mixture with sample extract.
