3.6.2. DPPH Radical Scavenging Activity

The DPPH assay was estimated according to Brand-Williams, Cuvelier, and Berset [52], with slight modification. A 0.1 mL volume of the sample was mixed with 0.9 mL of a 6 µM solution of DPPH• in 75% methanol. The absorbance was measured after 3 min of reaction at 515 nM. Here, 75% methanol was used as a blank. The scavenging effect was calculated using the formula:

$$\text{Scavenging activity} \left( \% \right) \ = \left[ 1 - \left( \text{A sample/A control} \right) \right] \times 100\tag{4}$$

where A sample is the absorbance of the mixture of sample and DPPH• ; A control is the absorbance of the control (DPPH• solution).

The results were expressed as Trolox equivalent antioxidant activity (TEAC) values (mM Trolox).
