Chitosan Coating Enhances the Antimicrobial Activity of Punica granatum L. Phenolic Compounds

The development of antibiotic resistance has become a global health challenge, resulting in approximately 800,000 deaths per year. The rapid rise in multidrug-resistant (MDR) pathogens has prompted an urgent need for antimicrobial alternatives. Punica granatum L. peel has long been valued for its rich bioactive polyphenols with potent antimicrobial properties. In this study, P. granatum L. peel extract (PGPE) was integrated with chitosan nanoparticles (CH-PGPE) to enhance antimicrobial efficacy while minimizing potential cytotoxicity. The antimicrobial potential of PGPE and CH-PGPE was evaluated with agar well diffusion, disk diffusion, and minimum inhibitory concentration (MIC) analyses against standard ATCC and clinical MDR strains of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. MTT assay evaluated the biocompatibility and anti-proliferative potential of PGPE on ARPE-19 (normal retinal pigment epithelial), HeLa (human cervical cancer), and A549 (human lung carcinoma) cell lines. PGPE exhibited antibacterial activity, and CH-PGPE reduced MIC values by approximately two-fold. Both PGPE and CH-PGPE demonstrated comparable or superior inhibition compared to several conventional antibiotics, particularly against MDR strains. The MTT assay revealed that PGPE was non-cytotoxic to normal ARPE-19 cells, while exhibiting the highest antiproliferative potency against A549 cells and a moderate inhibitory response in HeLa cells. The nanoparticle-supported formulation enhanced the antimicrobial efficacy of PGPE and also exhibited selective anti-proliferative activity against cancer cells without affecting normal cells.