*2.3. Free Radical Scavenging Using DPPH*

The free radical scavenging activity of the TTO and PMO against 2,2-diphenyl-1 picrylhydrazyl (DPPH) was measured according to the method described in [25]. First, EOs samples were diluted with methanol (50 μL mL<sup>−</sup>1); then, the sample was mixed with 4 mL DPPH solution (0.24 mg L−<sup>1</sup> in methanol). The control sample was prepared by mixing methanol with DPPH solution at the same volume. The mixture was mixed well and incubated in the dark at room temperature for 30 min; then, the absorbance was measured at 517 nm using a spectrophotometer (Unico UV-2000, UNICO company, Fairfield, NJ, USA). The free radical scavenging activity of each essential oil was calculated according to Equation (1).

$$\text{Free radical saving (\%)} = \text{I} (\text{A}\_{\text{control}} - \text{A}\_{\text{sample}}) / \text{A}\_{\text{control}} \text{I} \times 100 \tag{1}$$

where: *A control = absorbance of control sample*, and *A sample = absorbance of essential oil sample*.
