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

Abstract

Pomegranate tree possesses a vast ethnomedical hist ory and represents a phytochemical reservoir of heuristic medicinal value. In the pres ent study, total phenolics, antioxidant, and antibacterial activities of pomegranate peel we re determined by Folin–Ciocalteu, 2,2- diphenyl-1-picrylhydrazyl (DPPH) and disk-diffusion methods, respectively, and compared among the accessions. Methanolic extract g ives higher total phenolics than the water extract. Six phenolic compounds were identifi ed and quantified in pomegranate peel using the HPLC/ultraviolet method. The predomi nant compound was gallic acid, followed by ellagic acid, caffeic acid, p -coumaric acid, quercetin, and vanillic acid. Antioxidant activity expressed as IC 50 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 bo th high antioxidant and antibacterial properties. These findings support th e improvement and the selection for obtaining high products with well-defined functiona l properties. Key words : DPPH, Disc diffusion method, Polyphenols, Punica granatum L.