Enhanced antimicrobial efficacy and biocompatibility of albumin nanoparticles loaded with Mentha extract against methicillin resistant Staphylococcus aureus

In an effort to combat methicillin-resistant Staphylococcus aureus (MRSA), this study investigates the potential of mentha-loaded albumin nanoparticles (MLAN) as a novel antimicrobial agent. MLAN was synthesized by a desolvation method in which the mentha extract was encapsulated in albumin nanoparticles to increase stability and reduce toxicity. Characterization of the nanoparticles by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and X-ray Diffraction (XRD) confirmed their spherical morphology, a size range of 100-200 nm and uniform distribution. The encapsulation efficiency (EE%) and loading capacity (LC%) of MLAN were determined to be 80% and 72.73%, respectively, indicating a high effectiveness of the encapsulation process. Evaluation of cytotoxicity using the MTT assay revealed that MLAN exhibited significantly higher biocompatibility compared to aqueous Mentha extract and maintained cell viability at 85.1 ± 3.5% at the highest concentration tested (250 µg/mL). Antimicrobial evaluations against MRSA showed that MLAN had larger zones of inhibition and lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (0.39 mg/mL and 0.78 mg/mL, respectively) compared to the aqueous extract (MIC: 0.78 mg/mL, MBC: 1.56 mg/mL). In addition, real-time PCR showed that MLAN significantly downregulated the expression of key virulence genes (icaA, icaD and ebps) in MRSA, indicating a potential reduction in bacterial virulence. These results suggest that MLAN could be a promising alternative to conventional antibiotics with improved antimicrobial efficacy and reduced cytotoxicity. The study underlines the potential of combining plant extracts with nanotechnology for the development of new therapeutic approaches against antibiotic-resistant pathogens such as MRSA. Further in vivo studies are warranted to validate the clinical applicability of MLAN.