Antibacterial Activity of Sesamol against Methicillin-Sensitive and MethicillinResistant Staphylococcus aureus: An in Vitro Comparative Study

Abstract

Objective: To evaluate the in vitro antibacterial activity of sesamol against Methicillin-Sensitive Staphylococcus aureus (MSSA) and Methicillin-Resistant Staphylococcus aureus (MRSA), through the broth microdilution method. Study Design and Setting: In vitro experimental study, conducted at the Microbiology Laboratory, Ziauddin University Hospital (North Nazimabad Campus), Multi-Disciplinary Research Lab, Ziauddin University Clifton Campus, Karachi, from 1st September 2025 to 28th December 2025. Methodology: Sesamol (purity = 98%) was dissolved in 50% DMSO to obtain a 200 mg/mL stock solution. The antibacterial activity was evaluated using the Broth Microdilution Assay with several two-fold serial dilutions of sesamol against both drug-sensitive and resistant Staphylococcus aureus clinical isolates. The difference in MIC between the two groups was statistically processed by a Mann–Whitney U test. Results: Sesamol showed concentration-dependent antibacterial inhibitory actions against all the MSSA and MRSA strains tested. The Minimum Inhibitory Concentration (MIC) of sesamol for MSSA and MRSA was 1.5 mg/mL and 2.0 mg/mL, respectively. The difference in MIC between the two groups was found to be statistically non-significant(p=0.41) between the two groups Conclusion: Sesamol showed concentration-dependent antibacterial activity, though the difference between MSSA and MRSA was not statistically significant (p=0.41). Its MIC against MSSA and MRSA indicates possible antimicrobial activity against these pathogens and warrants further investigation. These results suggest that sesamol can be a potential natural antibacterial agent that may proceed for further pre-clinical studies