## 2 Materials and Methods
### Biochemical Determinations  
The frozen cell lysates were thawed and then centrifuged, and the obtained supernatant was used for the biochemical analysis. The results of the biochemical assays were converted into \(10^{6}\) cells. 2.6.1. Assay of the Activity of the Antioxidant Enzymes  
The activity of the antioxidant enzymes--superoxide dismutase, catalase and glutathione peroxidase--was determined according to the manufacturer's protocol, and the tests were purchased from Cayman Chemicals, Ann Arbor. MI, USA. A reaction of xanthine with a tetrazolium salt was used to form formazan to determine SOD activity, which was measured spectrophotometrically at 440-460 nm. The spectrophotometric method was also used to determine the GPx activity. To determine the GPx activity, a reduction reaction of cumene hydroperoxide to oxidized glutathione was used, which was then reduced, and was accompanied by a decrease in absorbance at 340 nm. The catalase activity was measured by reacting CAT with methanol, the product of which is formaldehyde, which was then measured spectrophotometrically using purpald as the chromogen. 2.6.2. Total Antioxidant Status (ABTS) Assay  
The total antioxidant potential was determined based on the ABTS radical method, which consists of the reaction of potassium persulfate and ABTS. The absorbance reduction was measured at 734 nm and then the potential was read from the standard curve for the Trolox rotatable [15]. 2.6.3. Lipid Peroxidation Assay  
The concentration of MDA, which is a marker of the lipid peroxidation process, was determined using a Bioxytech MDA-586 assay test kit (OxisResearch, Foster City, CA, USA). The absorbance of the product of the reaction of N-methyl-2-phenylindole (NPMI) with MDA at 45 \({}^{\circ}\)C was measured at 586 nm. 2.6.4. Statistical Analyses  
All data are expressed as the mean \(\pm\) the standard deviation of separate experiments. An ANOVA and [PERSON]'s post hoc test were used to evaluate the results of the experiments. The statistical calculations were performed using STATISTICA 12.0 and the statistical significance was defined at \(p<0.05\). 3. Results  
Resveratrol cytotoxicity against C32 and Colo829 malignant melanoma cells was assessed in this study, ranging from 50 uM to 1000 uM (Figures 1 and 2). The concentration of 500 uM was selected for the experiment due to a statistically significant decrease in the viability of both of the melanoma cells and thus the cytotoxic effect. Figure 1: Cell viability in amelanotic malignant cultures (C32) that had been exposed to resveratrol (between 50 and 1000 uM for 24 h). Each bar represents the mean \(\pm\) SD of two independent experiments. Statistical significance, \({}^{*}\)\(p<0.05\) vs. control (F = 24.31). The results of the activity of the antioxidant enzymes that constitute the first line of defense of a cell (SOD, GPx and CAT) that were obtained in this study indicate that, in both the C32 and Colo829 melanoma cells that had been exposed to resveratrol, there was a statistically significant reduction in the activity of these enzymes relative to the control cells (Figures 3-5). The addition of resveratrol to the melanoma cells caused a significant decrease in the SOD activity by 35% (C32) and 63% (Colo829). Moreover, the activity of GPx and CAT under the influence of resveratrol was also statistically significantly decreased by 34% (C32) and 61% (Colo829) for GPx and by 40% (C32) and 24% (Colo829) for CAT, respectively. Figure 3: Effect of resveratrol and an SMF on the SOD activity in the melanoma cell cultures (C32, Colo829). The results are presented as the mean \(\pm\) SD; a \(p\) < 0.05 vs. C (control); b \(p\) < 0.05 vs. (R) resveratrol (F = 54.43). Figure 2: Cell viability in melanoma malignant cultures (Colo829) that had been exposed to resveratrol (between 50 and 1000 \(\upmu\)M for 24 h). Each bar represents the mean \(\pm\) SD of two independent experiments. Statistical significance, \({}^{*}\)\(p\) < 0.05 vs. control (F = 32.03).