Phenolic Compounds, Antioxidant, and Antibacterial Activities of Peel Extract from Tunisian Pomegranate

Pomegranate tree possesses a vast ethnomedical history and represents a phytochemical reservoir of heuristic medicinal value. In the present study, total phenolics, antioxidant, and antibacterial activities of pomegranate peel were determined by Folin-Ciocalteu, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and disk-diffusion methods, respectively, and compared among the accessions. Methanolic extract gives higher total phenolics than the water extract. Six phenolic compounds were identified and quantified in pomegranate peel using the HPLC/ultraviolet method. The predominant compound was gallic acid, followed by ellagic acid, caffeic acid, p-coumaric acid, quercetin, and vanillic acid. Antioxidant activity expressed as IC50 varied among the cultivars and between solvents and was highly correlated with the total phenolics. All extracts were efficient against the five tested bacteria. Statistical analysis revealed three groups of accessions. The first group showed a high polyphenol compound that had both high antioxidant and antibacterial properties. These findings support the improvement and the selection for obtaining high products with well-defined functional properties.