Alternation of antibacterial, antibiofilm, and cytotoxic activities dependent on alkyl chain length of benzoate esters

AIM: This study aimed to evaluate the influence of alkyl chain length on the antibacterial, antibiofilm, and cytotoxic properties of benzoate esters commonly used in the fragrance industry, and to assess their suitability as biocompatible biofilm inhibitors. METHODS AND RESULTS: n-Butyl, n-pentyl, n-hexyl, and n-heptyl benzoate esters were synthesized via acid-catalyzed Fischer esterification and characterized by FT-IR, NMR, and GC-MS techniques. Antibacterial and antibiofilm activities were investigated against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853, while cytotoxicity was assessed using an ISO 10993-5-compliant MTT assay. The antibacterial activity of all compounds was low, with growth inhibition values of less than 33% relative to untreated control cultures. In contrast, strong antibiofilm biomass inhibition was observed, particularly against S. aureus, with inhibition rates up to 90.49%. Medium-chain derivatives, especially n-pentyl and n-hexyl benzoates, showed the most pronounced and consistent antibiofilm effects. Cytotoxicity results demonstrated dose-dependent biocompatibility, with n-hexyl and n-heptyl benzoates maintaining high cell viability at concentrations ≥0.0125%. CONCLUSIONS: Alkyl chain length is associated with differences in antibiofilm-related behavior and biocompatibility of benzoate esters but has a limited impact on direct antibacterial activity. These findings indicate that benzoate esters are more suitable for applications involving reduction of biofilm biomass and surface-associated microbial control rather than as conventional antimicrobial compounds, suggesting their potential relevance in cosmetic, medical, and industrial applications.