S-alkylated/aralkylated 2-(1H-indol-3-yl-methyl)-1,3,4-oxadiazole-5-thiol derivatives. 2. anti-bacterial, enzyme-inhibitory and hemolytic activities

Purpose: To evaluate the antibacterial, enzyme-inhibitory and hemolytic activities of S-alkylated/aralkylated 2-(1H-indol-3-ylmethyl)-1,3,4-oxadiazole-5-thiol derivatives. Methods: Antibacterial activities of the compounds were evaluated using broth dilution method in 96 well plates. Enzyme inhibitory activities assays were investigated against α-glucosidase, butyrylcholinesterase (BchE) and lipoxygenase (LOX) using acarbose, eserine and baicalien as reference standards, respectively. A mixture of enzyme, test compound and the substrate was incubated and variation in absorbance noted before and after incubation. In tests for hemolytic activities, the compounds were incubated with red blood cells and variations in absorbance were used as indices their hemolytic activities. Results: The compounds were potent antibacterial agents. Five of them exhibited very good antibacterial potential similar to ciprofloxacin, and had minimum inhibitory concentrations (MIC) of at least 9.00 ± 4.12 µM against S. aureus, E.coli, and B. subtilis. One of the compounds had strong enzyme inhibitory potential against α-glucosidase, with IC₅₀ of 17.11 ± 0.02 µg/mL which was better than that of standard acarbose (IC₅₀ 38.25 ± 0.12 µg/mL). Another compound had 1.5 % hemolytic activity. Conclusion: S-Alkylated/aralkylated 2-(1H-indol-3-ylmethyl)-1,3,4-oxadiazole-5-thiol deviratives with valuable antibacterial, anti-enzymatic and hemolytic activities have been successfully synthesized. These compounds may be useful in the development of pharmaceutical products.