The effect of selected herb extracts on superoxide dismutase activity in Jurkat cells

Background: Numerous dietary and medicinal herbs containing high levels of polyphenolic compounds exert antioxidative properties which are beneficial in the prophylaxis of many diseases, including cancer and atherosclerosis. Superoxide dismutase (SOD) is an enzyme scavenging superoxide radicals. It is hypothesized that some antioxidative effects of polyphenols may occur through interaction with this enzyme. Objective: The aim of this study was to assess the influence of polyphenolic herb extracts on SOD activity in human leukemia cells. Material and Methods: Aqueous extracts comtaining polyphenolic fractions were prepared from Thymus serpyllum (Ts), Thymus vulgaris (Tv), Majorana hortensis (Mh), and Mentha piperita (Mp). The experiments were conducted on human Jurkat cells, which were exposed to the Ts, Tv, Mh, or Mp polyphenolic fractions at concentrations of 10-500 μg/ml for 0.5, 1, or 2 hours. SOD activity was measured spectrophotometrically using a modified RANSOD kit protocol. The results were analyzed using the Repeated Measures Analysis of Variance (ANOVA) design in Statistica version 6 software. All effects were regarded as significant at a significance level of p < 0.05. Results: The analysis of the results suggests a stimulatory effect of the extracts which was most evident at shorter incubation times (0.5 and 1 hour) and at concentrations of 50 and 500 μg/ml. However, in the case of Ts and Mh, 2-hour incubation at the highest concentration (500 μg/ml) also resulted in a significant increase in enzymatic activity. In contrast, the lowest concentration of the extracts (10 μg/ml) exhibited no significant effect on SOD. Conclusions: The stimulation of SOD activity in Jurkat cells under the influence of Lamiaceae herb polyphenolic fractions suggests that some antioxidative effects of polyphenols may result from direct interaction with the free radical-scavenging enzyme. © Copyright by Silesian Piasts University of Medicine in Wrocław.