Previous in vitro studies have demonstrated a pronounced cytotoxic effect of the thiazole derivative N-(5-Benzyl-13-thiazole-2-yl)-35-dimethyl-1-benzofuran-2-carboxamide (BF1) on tumor cells. Additionally, it has been determined that scavengers of reactive Oxygen species (ROS) significantly reduce the cytotoxic effect of BF1. In this study, the influence of BF1 on the activity of superoxide dismutase (SOD) and catalase (CAT), both normally and in the presence of ascorbic acid, in mouse Nemeth-Kellner lymphoma (NK/Ly) cells has been studied to evaluate the possible role of antioxidant activity during the action of this substance. The experiments were performed using nonlinear male mice weighing 20–30 g. Intraperitoneal inoculation of 10–15 million cancer cells into the mice induced the ascites form of lymphoma. The thiazole derivative (BF1) was dissolved in dimethyl sulfoxide and added to the test samples at 1, 10, and 50 μM final concentrations. Superoxide dismutase (SOD) and catalase (CAT) activities were determined spectrophotometrically in a homogenate of the lymphoma cells after incubation with the drug for 30 minutes. The baseline level of SOD in the lymphoma of the mice was 0.33±0.02 activity units/min×mg protein. BF1 significantly increased the enzyme activity by 35 % and 29 % at concentrations of 10 (p<0.01) and 50 μM (p<0.05), respectively. The baseline level of CAT activity was 4.61±0.17 nmoles H2O2/min×mg protein, and this significantly decreased by 15 % (p<0.05) and 20 % (p<0.01) following the action of the thiazole derivative at a concentration of 10 and 20 μM, respectively. The increase of SOD activity, coupled with a decrease or absence of changes in CAT activity, may be cytotoxic to cancer cells. Simultaneously, upon the addition of ascorbic acid as a scavenger of ROS to the environment, the activities of SOD and CAT did not change under the action of BF1 at any of the investigated concentrations. Therefore, the effect of the thiazole derivative BF1 has been canceled in the presence of ROS scavengers in the environment. This may indicate the dependence of the cytotoxic effect of BF1 on the presence of ROS in tumor cells.
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