1,3-benzoxathiol-2-one and 1,3-benzothiazole compounds as potential anticancer and antimicrobial Agents

Over the years, cancer and infectious diseases have appeared among the leading causes of death worldwide. The data herein highlights the need for new prototypes to design more potent and selective chemotherapeutics, as well as new, nontraditional antimicrobial agents. The main goal of this study was to evaluate some 1,3-benzoxathiol-2-one and 1,3-benzothiazole derivatives for their anticancer, antibacterial and antifungal activities. The compounds were screened for in vitro anticancer activity against melanoma (SKMEL-19), ascitic fluid (AGP-01) and breast (MCF-7) cancer cell lines using an MTT assay. The toxicity profile against erythrocytes and the normal human fibroblast cell line (MRC-5) was also evaluated. Besides that, in vitro Antimicrobial Screening Test (AST), Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) assays were performed against Gram-positive and Gram-negative bacteria as well as against Candida species. All tests were performed according to CLSI protocols, using vancomycin, ciprofloxacin and ketoconazole as reference drugs. The derivative 6-methoxy-benzo[d][1,3]oxathiol-2-one (7) exhibited considerable cytotoxic activity (IC₅₀ = 3.3 μM) against SKMEL-19, and the compound (E)-4-((2-(benzo[d]thiazol-2-yl)hydrazono)methyl)benzene-1,2,3-triol) (16m) showed good activity against all Candida species (MIC 8-32 μg mL^-1). The MBC/MIC ratio for 16l and 16m derivatives classified them as bactericidal agents against Gram-positive bacteria. Compound 16m presented a fungistatic profile against Candida albicans and non-albicans species evaluated. Overall, the in vitro results pointed to the potential of derivatives 7 and 16m as new anticancer and antifungal prototypes, respectively, to be further explored, since they also presented low toxicity profiles. (author)