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. <i>Punica granatum</i> L. peel has long been valued for its rich bioactive polyphenols with potent antimicrobial properties. In this study, <i>P. granatum</i> 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 <i>Escherichia coli</i>, <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeruginosa</i>, and <i>Staphylococcus aureus</i>. 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.