Beta-Blocker Drugs, Antioxidant Enzymes, Glutathione-S-Transferase, Superoxide Dismutase, Catalase, Glutathione Peroxidase

The objective of the study is to predict the medical purposes of beta-blocker drugs beside to their antihypertensive action, by evaluating their effects on antioxidant defense enzymes. In order to accomplish this aim, firstly propranolol hydrochloride and metoprolol tartrate solubility and stability was performed using UV spectrum of drugs measured at maximum wavelengths of 290nm and 275nm, respectively. Then, their effects on the activity of antioxidant enzymes were studied for the first time with commercially available or isolated enzyme targets. Antioxidant effects of beta-blocker drugs were analyzed by measuring the changes on the activity of antioxidant enzymes; glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) upon exposure to various concentrations of drugs. The results have shown that the stability of propranolol hydrochloride in water, as best solvent, was up to one month when stored at -200C. Metaprolol was injectable, ready forivuse form, so no stability testing required. The enzyme assays showed that the inhibitory effects of propranolol and metoprolol on superoxide dismutase (SOD) were about 100%, the effect on glutathione peroxidase (GPx) activities were about 80% with IC50 of 0.0052g/L for propranolol and 90% with IC50 of 0.00072g/L for metoprolol. The inhibitory effects of both drugs on glutathione-S-transferase (GST) enzyme activity were less than 20%, however, no inhibitory effects were observed on catalase (CAT) enzyme activity.