Antibacterial Activity of Pomegranate (Punica granatum L.) Seed and Peel Alcoholic Extracts on Staphylococcus aureus and Pseudomonas aeruginosa Isolated From Health Centers

Introduction: Pomegranate (Punica granatum L.) is an ancient fruit with numerous phytochemical bioactive compounds. In this study, the antibacterial activity of ethanolic extracts of pomegranate peels and seeds were investigated against Pseudomonas aeruginosa and Staphylococcus aureus clinical isolates from Tabriz health centers (2017). Materials and Methods: The ethanolic extracts of pomegranate seed and peel were prepared and GC-MS chromatogram analyzed using Agilent 7890B gas chromatography. The antibacterial activities of extracts were evaluated by agar diffusion and microbroth dilution methods against clinical isolates of P. aeruginosa (n = 10), S. aureus (n = 10) and standard strains. Results: The ethanolic extracts of pomegranate seed and peel showed inhibitory effects on clinical isolates of P. aeruginosa and S. aureus. The minimum inhibitory concentrations (MICs) of pomegranate peel and seed extracts were 12.5 and 25.0 mg/mL, respectively. In addition, the minimum bactericidal concentrations (MBCs) of pomegranate peel and seed extracts were found to be 25.0 and 50 mg/mL, respectively. In all of the studied bacterial isolates, the MICs and MBCs values for pomegranate seed extract were significantly higher than those for pomegranate peel extract (P < 0.05). The mean inhibition zones and MICs values indicated that the antibacterial activity of pomegranate peel extract had more potent effect on studied bacterial isolates compared with pomegranate seed extract. Conclusions: According to the findings, the pomegranate peel and seed extracts showed antibacterial activities against bacterial isolates in this study; however, the peel extract had a stronger antibacterial effect than the seed extract. Therefore, further studies including cell toxicity assay and in vivo investigations are recommended.