Abstract
The aim of the present work was to design and synthesize 4-(4-bromophenyl)-5-((5-((quinolin-8-yloxy)methyl)-1,3,4-oxadiazol-2-ylthio)methyl)-4H-1,2,4-triazole-3-thiol derivatives and evaluate them for in-vitro Antioxidant, Antibacterial, Antihypertensive activities against standards. Antioxidant properties by DPPH, 2-Deoxyribose assay and Lipid peroxidation assay against ascorbic acid, Mannitol and R-tocopherol standards were evaluated respectively. Antibacterial activity against Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae were evaluated. Angiotensin-I-converting enzyme (ACE-I) inhibition was studied by using standard lisinopril. 3 out of 10 synthesized compounds showed good in-vitro antioxidant and antibacterial activities. In antioxidant activity the compound 4d, which is 2-methyl 5,7-dichloro substitution on core 8-hydroxyquinoline showed least IC50(highest active) value i.e. 98.8 mg/ml in DPPH against 106.12 mg/ml of standard ascorbic acid, 127.2 mg/ml in 2-deoxyribose assay against 130.4 mg/ml of the standard mannitol and 131.6 mg/ml in lipid peroxidation assay against 138.81 mg/ml of standard R-tocopherol. Compounds 4b, 4c, 4a and 3d showed moderate antioxidant activity. The compounds 3d and 4d were found to have higher antimicrobial activity on E. coli and S. aureus. The compounds 4e, 4a and 4d showed % inhibition of 85.81, 68.53 and 55.66 at higher concentrations (1000 µg/µl) respectively when compared to standard lisinopril (73.33 % inhibition) in ACE-I inhibitory activity. Halo substituted 8-hydroxyquinoline moiety may be responsible for the effective antibacterial and antioxidant activities. Similarly methyl substituted 8-hydroxyquinoline moiety may be responsible for the effective ACE-I activity. Hence, further studies are also required to confirm the influence of electron withdrawing and donating group on the substitution moiety.
