Separation and Antibacterial Activity of Flavonoids and Alkaloids from Pomegranate Peel by HPLC

Background: The rising incidence of antibiotic-resistant bacteria has necessitated the urgent exploration of alternative antimicrobial agents derived from natural sources. Pomegranate peels are rich in bioactive compounds known for their antibacterial and antioxidant properties, making them a promising option for managing pathogenic and drug-resistant bacteria. Objective: This study aimed to investigate the antibacterial efficacy of active compounds extracted from pomegranate peels against antibiotic-resistant bacterial strains, namely Klebsiella spp. and Pseudomonas aeruginosa, and to evaluate their potential as natural antimicrobial alternatives. Methodology: Active compounds were extracted from pomegranate peels using aqueous and alcoholic solvents and subsequently isolated using high-performance liquid chromatography (HPLC). The antibacterial activity of the extracts and isolated compounds was evaluated against antibiotic-resistant strains of Klebsiella spp. and Pseudomonas aeruginosa using inhibition zone assays at varying concentrations. Statistical analysis was performed to determine dose–response relationships and the significance of the observed effects. Results: The results indicated that both aqueous and alcoholic pomegranate peel extracts were rich in bioactive compounds, including water-soluble vitamins (such as vitamin C and B-complex vitamins), alcohol-soluble vitamins (such as vitamin E), flavonoids (particularly quercetin), and alkaloids. All identified compounds exhibited significant antioxidant and antibacterial activities. The compounds produced inhibition zones ranging from 5 to 15 mm in diameter against Klebsiella spp. In contrast, alcohol-soluble vitamins, flavonoids, and alkaloids showed superior activity against Pseudomonas aeruginosa, with inhibition zones reaching up to 30 mm. Statistical analysis demonstrated a strong dose-dependent inhibitory effect on bacterial growth, with results achieving high significance (p ≤ 0.001). Conclusions: The findings of this study demonstrate that bioactive compounds extracted from pomegranate peels possess potent antibacterial activity against antibiotic-resistant bacterial strains. These results support the potential use of pomegranate peel extracts as a natural and effective alternative for controlling aggressive and drug-resistant bacteria, thereby contributing to the development of novel antibacterial therapies.