Antimicrobial activity of quinoxaline 1,4-dioxide with 2- and 3-substituted derivatives

Quinoxaline is a chemical compound that presents a structure that is similar to quinolone antibiotics. The present work reports the study of the antimicrobial activity of quinoxaline N,N-dioxide and some derivatives against bacterial and yeast strains. The compounds studied were quinoxaline-1,4-dioxide (QNX), 2-methylquinoxaline-1,4-dioxide (2MQNX), 2-methyl-3-benzoylquinoxaline-1,4-dioxide (2M3BenzoylQNX), 2-methyl-3-benzylquinoxaline-1,4-dioxide (2M3BQNX), 2-amino-3-cyanoquinoxaline-1,4-dioxide (2A3CQNX), 3-methyl-2-quinoxalinecarboxamide-1,4-dioxide (3M2QNXC), 2-hydroxyphenazine-N,N-dioxide (2HF) and 3-methyl-N-(2-methylphenyl)quinoxalinecarboxamide-1,4-dioxide (3MN(2MF)QNXC). The prokaryotic strains used were Staphylococcus aureus ATCC 6538, S. aureus ATCC 6538P, S. aureus ATCC 29213, Escherichia coli ATCC 25922, E. coli S3R9, E. coli S3R22, E. coli TEM-1 CTX-M9, E. coli TEM-1, E. coli AmpC Mox-2, E. coli CTX-M2 e E. coli CTX-M9. The Candida albicans ATCC 10231 and Saccharomyces cerevisiae PYCC 4072 were used as eukaryotic strains. For the compounds that presented activity using the disk diffusion method, the minimum inhibitory concentration (MIC) was determined. The alterations of cellular viability were evaluated in a time-course assay. Death curves for bacteria and growth curves for S. cerevisiae PYCC 4072 were also accessed. The results obtained suggest potential new drugs for antimicrobial activity chemotherapy since the MIC's determined present low values and cellular viability tests show the complete elimination of the bacterial strain. Also, the cellular viability tests for the eukaryotic model, S. cerevisiae, indicate low toxicity for the compounds tested.