The values were compared to a control to determine the percentage of inhibition of nitrite reaction with Griess reagent, depicted by the PCs, as an index of the NO scavenging activity (Marcocci et al., 1994). The MEK inhibitor measurement of a PC’s scavenging activity against the radical (DPPH ) was performed in accordance with Choi et al. (2002). Briefly, 85 μM DPPH was added
to a medium containing different PCs concentrations. The medium was incubated for 30 min at room temperature, and the decrease in absorbance measured at 518 nm depicted the scavenging activity of the PCs against DPPH (Puntel et al., 2009). The values are expressed as percentage of inhibition of DPPH absorbance in relation to the control values without the PCs. The deoxyribose degradation assay was performed according to Puntel et al. (2005). Briefly, Vorinostat solubility dmso the reaction medium was prepared containing the following reagents at the final concentrations indicated: PCs (concentrations indicated in the figures), deoxyribose (3 mM) ethanol (5%), potassium
phosphate buffer (0.05 mM, pH 7.4), FeSO4 (50 μM), and H2O2 (500 μM). Solutions of FeSO4 and H2O2 were made prior to use. Reaction mixtures were incubated at 37 °C for 30 min and stopped by the addition of 0.8 mL of trichloroacetic acid (TCA) 2.8%, followed by the addition of 0.4 mL of thiobarbituric acid (TBA) 0.6%. Next, the medium was incubated at 100 °C for 20 min and the absorbance was recorded at 532 nm (Gutteridge, 1981 and Halliwell and Gutteridge, 1981). Standard curves of MDA were made for each experiment to determine the MDA generated by the deoxyribose
degradation. The values are expressed as a percentage of control values (without PCs). Statistical significance was assessed by one-way ANOVA, followed by the Student–Newman–Keuls Metalloexopeptidase test for post-hoc comparison and two-way ANOVA. Results were considered statistically significant at values of p < 0.05, p < 0.01 and p < 0.001. The chemical structure of a PC is shown in Fig. 1A. The chemical structures of MPCs (copper-PC, manganese-PC, zinc-PC, and iron-PC) were obtained by replacing X with one of the following metals: Cu2+, Mn2+, Zn2+, or Fe2+, respectively (Fig. 1B). The PC significantly decreased the SNP-induced lipid peroxidation in liver, kidney, and brain tissues of mice at concentrations ranging from 1 to 100 μM (Fig. 2, Fig. 3 and Fig. 4, respectively). Similarly, cooper-PC (Fig. 2, Fig. 3 and Fig. 4), and manganese-PC (Fig. 2, Fig. 3 and Fig. 4) significantly decreased SNP-induced lipid peroxidation in liver, kidney, and brain at all tested concentrations (1–100 μM). Moreover, the manganese-PC was able to decrease the lipid peroxidation to levels lower than those of the controls, both in liver, and brain tissues (Fig. 2 and Fig. 4, respectively).