## 2 Materials and Methods
### Evaluation of Antioxidant Activity  
The antioxidant activities of the extracts, obtained at optimized conditions, were evaluated by the DPPH, ABTS, FRAP, and CUPRAC assays. Each sample was examined in triplicate. Trolox solutions were prepared in appropriate concentrations for quantitation purposes, and the results were expressed as Trolox equivalents in nmol per g of dry parsley for all the antioxidant tests performed.  
The capacity of extracts to scavenge the free radical of DPPH was evaluated using the method from [PERSON] et al. [20] with minor modifications. An aliquot of the extract (25 to 100 \(\upmu\)L) or appropriate standard solution of Trolox was diluted with methanol up to 0.9 mL. Then, 0.1 mL of 0.6 mM DPPH reagent in methanol was added, followed by vigorous stirring. After 15.0 min in the dark, the absorbance was measured at 515 nm against a reference sample containing methanol.  
Determination of ABTS radical scavenging activity of samples was performed using the method from [PERSON] et al. [21] with minor modifications. ABTS radical cation (ABTS\({}^{\star+}\)) was produced by the oxidation of ABTS with potassium persulfate (K\({}_{2}\)S\({}_{2}\)O\({}_{8}\)). The ABTSTS\({}^{\star+}\) was generated by reacting 7 mmol/L stock solution of ABTS with potassium persulphate in a final concentration equal to 2.45 mmol/L. The ABTSTS\({}^{\star+}\) working solution was prepared by dilution of the stock solution using distilled water to give an absorbance of 0.700 at 734 nm. Aliquots of parsley extracts (25 to 100 \(\upmu\)L) or appropriate amounts of Trolox standards were diluted to 1.0 mL with working ABTSTS\({}^{\star+}\) solution and were vigorously stirred. Samples remained for 15.0 min in the dark at ambient temperature and the absorbance was measured at 734 nm. The ability of the extracts to scavenge the ABTSTS\({}^{\star+}\) was evaluated relative to a reference sample that did not contain any quantity of extract.  
The reducing potential of the samples was determined using the FRAP assay as described by [PERSON] and [PERSON] [22]. The method is based on the reduction of the Fe\({}^{3+}\)--tripyridyl triazine complex to its ferrous-colored form at low pH in the presence of antioxidants. The FRAP reagent was freshly prepared and contained 0.2 mL of a 10 mM TPTZ (2,4,6-tripyrid-s-triazine) solution in 40 mM HCl plus 0.2 mL of 20 mM FeCl\({}_{3}\bullet\)6H\({}_{2}\)O plus 0.2 mL of 3.0 M acetate buffer, pH 3.6. Aliquots of extracts (10 to 50 \(\upmu\)L) were transferred in test tubes and dissolved up of 900 \(\upmu\)L with distilled water, followed by addition of 300 \(\upmu\)L of FRAP solution and vigorous stirring. The samples were incubated for 10 min in a 37 \({}^{\circ}\)C water bath, and the absorbance was measured at 593 nm.  
The reducing capacity of the samples was also determined using the CUPRAC assay according to [PERSON] et al. [23]. Aliquots of parsley extracts (10 to 50 \(\upmu\)L) were transferred in test tubes and diluted with 300 \(\upmu\)L of 10 mM CuCl\({}_{2}\bullet\)2H\({}_{2}\)O, 7.5 mM neocuproine, and 1 mM CH\({}_{3}\)COONH\({}_{4}\) buffer solution with pH = 7.0, followed by the addition of distilled water up to the volume of 1200 \(\upmu\)L. The samples were well stirred and remained at room temperature for 30 min. The absorbance of the samples was then measured at 450 nm.