Linoleic Fatty Acid from Rwandan Propolis: A Potential Antimicrobial Agent Against Cutibacterium acnes

Acne is a very common skin condition that causes pimples in 80% of adolescents despite the many effective treatments developed. Various compounds have been employed in the treatment of acne, including erythromycin ointments and antiseptics, yielding mixed results. The rise in erythromycin-resistant C. acnes strains has driven the pursuit of new antimicrobial agents, especially those obtained from natural sources. Propolis that was collected in Rwanda was extracted, fractioned, and analyzed for its activity against C. acnes growth in accordance with NCLSI guidelines. Our work revealed that linoleic acid has a significant effect on C. acnes growth at a low concentration (16 µg/mL). A comparison of the antimicrobial activities of a broad panel of well-known fatty acids revealed a specific mode of action for linoleic acid, characterized by a significant membranotropic effect on Bacillus cereus established by measuring extracellular ATP levels as an indicator of membrane permeability. Our data suggest that linoleic acid is effective against C. acnes and could be a promising candidate for developing a propolis-based ointment for acne treatment.