Effective treatment of central nervous system (CNS) infections remains a major challenge, as most therapeutic agents do not efficiently cross the blood–brain barrier (BBB) and the blood–cerebrospinal fluid barrier (BCSFB). Coumarin derivatives are of particular interest due to their broad pharmacological activity, favorable safety profile, and potential to penetrate biological barriers. Eight novel coumarin-based peptidomimetics functionalized with trifluoromethyl or methyl scaffolds were synthesized and evaluated as antimicrobial agents with the ability to cross the blood–brain barrier. Antimicrobial activity of the investigated compounds was tested against Staphylococcus aureus and multiple Escherichia coli strains (K12, R2, R3, R4) using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Cytotoxicity was assessed in vitro in BALB/c-3T3 mouse fibroblasts and αT3-1 pituitary gonadotrope cells using the MTT assay. In vivo studies were performed in sheep to assess transfer of the compounds from blood to cerebrospinal fluid (CSF). All synthesized derivatives demonstrated antimicrobial activity and acceptable cytotoxicity, comparable to those of clinically used antibiotics. CF3-modified coumarin peptidomimetics show promise as antimicrobial agents with the potential to penetrate the BBB/BCSFB. These findings support further investigation of coumarin-based scaffolds as a platform for the development of novel therapeutics for CNS infections.
