Hamadan University of Medical Sciences Avicenna Journal of Clinical Microbiology and Infection 2383-0298 13 3 2026 09 29 Antibacterial Properties of a Boswellia serrata Nanoemulsion Gel in Comparison to Its Hydroalcoholic Extra 152 158 10.34172/ajcmi.3780 EN Erfan Ebrahiminoghani https://orcid.org/0009-0006-8638-9409 Reihaneh Alsadat Mahmoudian Amir Tavakoli Kareshk Ebrahim Shafaei Parisama Ahmadizaveh Atena Mansouri https://orcid.org/0000-0003-0456-675X Journal Article 10.34172/ajcmi.3780 2025 09 08 2026 07 05 Introduction: Bacterial infections are a major health concern worldwide. Although antibiotics are widely used as cost-effective treatments, the rise of multidrug-resistant bacteria has limited their efficacy, increasing the search for alternative antimicrobial agents, particularly plant-derived products. Boswellia serrata, rich in bioactive compounds, has recently been investigated for antibacterial potential. This study evaluated the antibacterial activity of a B. serrata nanoemulsion-based gel compared with its hydroalcoholic extract. Methods: Bacterial strains, including Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (ATCC 9997), Staphylococcus aureus (ATCC 25923), and Enterococcus faecalis (ATCC 29212), were tested. Nanoemulsions were characterized using dynamic light scattering and transmission electron microscopy. Moreover, the functional groups of the extract and gel were examined by Fourier-transform infrared spectroscopy. Antibacterial activity was assessed by the microbroth dilution method to determine the minimum inhibitory concentration (MIC). Results: The hydroalcoholic extract demonstrated MICs of 20 mg/mL for S. aureus and P. aeruginosa,>20 mg/mL for E. coli and K. pneumoniae, and 2.5 mg/mL for E. faecalis. Furthermore, the nanoemulsion showed MICs of<50 mg/mL for E. coli, K. pneumoniae, and P. aeruginosa, as well as 25 mg/mL and 6.5 mg/mL for S. aureus and E. faecalis. The gel formulation also displayed MICs of<50 mg/mL for E. coli, K. pneumoniae, and P. aeruginosa, as well as 12.5 mg/mL and 6.25 mg/mL for S. aureus and E. faecalis. Conclusion: Both formulations displayed antibacterial activity, particularly against Gram-positive bacteria. The hydroalcoholic extract was more potent, suggesting promise as a natural antimicrobial agent.