Antioxidant and Antimicrobial Activities of Tunisian Azarole (<i>Crataegus Azarolus</i>L.) Leaves and Fruit Pulp/Peel Polyphenolic Extracts

Abstract

The polyphenolic extracts prepared from Tunisian azarole (Crataegus azarolus, Rosaceae family) leaves, fruit peel, and pulp parts were investigated. The evaluation of the free 2,2-diphenyl-2-picrylhydrazyl radical-scavenging activity in comparison to that of Trolox, a synthetic antioxidant, showed that the stronger properties were obtained from leaf material followed by fruit peel (2.026 and 1.607 mmol Trolox equivalent antioxidant capacity/g of fresh weight, respectively), whereas fruit pulp extract exhibited weak antioxidant potential (0.883 mmol Trolox equivalent antioxidant capacity/g of fresh weight). Using reverse phase-high phase liquid chromatography-diode array detector and ESI-MS, the phenolic compounds of the extracts were qualitatively and quantitatively determined. The total phenolic content of leaves and fruit peel and pulp were found to be about 152.38, 142.46, and 26.31 mg/100 g of fresh weight, respectively. Isoquercitrin was the main phenolic in the leaves (44.9%), whereas hyperosid (72.01%) and epicatechin (68.41%) were the most abundant compounds in the fruit peel and pulp, respectively. The assessment of the antimicrobial activity of the extracts against a range of Gram positive and Gram negative bacteria revealed that Tunisian azarole leaves and fruit peel extracts exhibited strong potential for inhibiting bacterial growth, especially Staphylococcus aureus and Streptococcus faecalis. minimum inhibitory concentrations and minimum bactericidal concentrations were found in the range of 59.35–118.71 and 42.32–63.49 μg/ml of fruit peel and leaves extracts, respectively.