Antimicrobial activity and antioxidant potential of the methanolic leaf extracts of three cultivars of date palm trees (Phoenix dactylifera) from Saudi Arabia

Abstract

The date palm tree (Phoenix dactylifera) is one of the oldest cultivated plants ever known; it is considered as the life tree for Arabs. However, no adequate information about the bioactivity of the leaves. In this study, the methanol extract of leaves demonstrated the presence of some compounds with potential biomedical properties for human, which were cardiac steroids, flavonoids, phenols/polyphenols, phytosterols, quinines, saponins, tannins and resin. The results of the antimicrobial test indicate that the methanol leaf extracts of the three date palm cultivars contained potential antibacterial agents, particularly against Gram-positive bacteria and no antifungal effect detected against Candida albicans. The most susceptible bacteria were Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus and Enterococcus faecalis, respectively.The antioxidant activities of extracts of different leaf cultivars obtained with methanol were also investigated, using DPPH (2, 2-diphenyl-2-picrymhydrasyl hydrate)radical-scavenging activity assay, all extracts exhibited considerable antioxidant potential. The current investigation suggests that leaves of date palm can be used as a promising source for natural antibacterial and antioxidant drugs.