Antimicrobial Effect of Boswellia serrata Resin’s Methanolic Extracts Against Skin Infection Pathogens

Frankincense resin (Boswellia serrata), native to arid regions of India, the Middle East, and parts of Africa, has been highly valued for its medicinal properties. This study evaluated the antimicrobial potential of methanolic extracts of Boswellia serrata resin against Staphylococcus aureus, Pseudomonas aeruginosa, and Listeria monocytogenes. High-performance thin-layer chromatography (HPTLC) coupled with bioautography identified bioactive zones, while Liquid Chromatography–Mass Spectrometry (LC-MS) quantified the phenolic and terpenoid compounds. The cytotoxicity was assessed on HaCaT human keratinocyte cells to evaluate the safety for dermatological applications. The results demonstrated significant antibacterial activity, particularly against S. aureus and L. monocytogenes. The bioautograms revealed that samples from central and southern Serbia showed the highest antimicrobial effect against the tested bacterial strains. The active compounds included 11-keto-β-boswellic acid (up to 3733.96 μg/g), gallic acid (110.93 μg/g), and naringenin (53.13 μg/g). Cytotoxicity assays confirmed non-toxic effects at 10 µg/mL, with sample 6 enhancing the keratinocyte viability by 137%, while higher concentrations (50 µg/mL) showed variable cytotoxicity. These findings highlight the potential of B. serrata resin as a natural antimicrobial agent, particularly against antibiotic-resistant pathogens. Its therapeutic applicability in pharmaceutical and cosmetic formulations is promising provided that dosing ensures a balance between efficacy and safety.