Antimicrobial and antioxidant activities of substituted halogenated coumarins

Abstract

Pathogens frequently display resistance to current drugs, which frequently lack selectivity/efficacy and have detrimental side effects. Thus, there is a constant need for novel therapeutic agents. Coumarins belong to the family of lactones, having a benzopyrone system that can be isolated from plants as well as total synthesis that can be carried out in the laboratory. To date, many chemical reactions have been established that can be used to synthesize coumarins. The synthesis of coumarins and their derivatives has attracted the attention of organic and medicinal chemists, as these are widely used as fragrances, pharmaceuticals and agrochemicals. In the present study, the antimicrobial and antioxidant activities of substituted coumarin analogue compounds have been screened. 3-(2-bromoacetyl)-2H-chromen-2-one (CMRN3) and 3-(2, 2-dibromoacetyl)-2H-chromen-2-one (CMRN6) showed bacterial growth inhibition for all the tested species except Klebsiella pneumonia and Bacillus stearothermophilus. CMRN4 and CMRN5 displayed moderate bacterial inhibition against Bacillus cereus, Micrococcus luteus, Staphylococcus aureus. CMRN3 and CMRN6 had a minimum inhibition concentration at 0.75 mg/ml against B. cereus, Bacillus coagulans, and Streptococcus faecalis. They displayed a minimum inhibitory concentration (MIC) of 1.5 mg/ml against Escherichia coli and S. aureus. (CMRN5) displayed an MIC at 0.75 mg/ml against M. luteus and 1.5 mg/ml against S. aureus. Compounds3-(2-bromoacetyl)- 6-chloro-2H-chromen-2-one (CMRN4), 3-(2-aminothiazol-4-yl)-6-bromo-2H-chromen-2-one(CMRN7), 3- acetyl-6-bromo-2H-chromen-2-one (CMRN1) exhibited potent antioxidant activity at 85, 61 and 56%, respectively, as evaluated by the DPPH free radical method.