Antibacterial activities of extracts of leaf, fruit, seed and bark of Phoenix dactylifera

Abstract

The antibacterial activities of different parts of local Phoenix dactylifera were investigated in vitro. Dried leaf, fruit, seed and tree bark were extracted with water, methanol and acetone. Antibacterial property of the extracts was evaluated against Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa using the disc diffusion method. Overall analysis of the antibacterial activity of various extracts revealed that the highest inhibitory activity was produced by the fruit extract (18.2 ± 0.55 mm) as compared to the leaf, bark and seed extracts. All the extracts from the different parts of the plant showed antibacterial activity against most tested microorganisms. On the whole, aqueous extracts have the least antibacterial activity as compared to methanol and acetone extracts. The antibacterial activity against the Gram-positive strains was the highest in the acetone fruit extract against S. aureus (18.2 ± 0.55 mm). The most active extract against Gram-negative bacteria was methanol extract from the leaves with a 13.5 ± 0.33 mm inhibition zone for E. coli followed by 12.5 ± 0.88 mm for P. aeruginosa. Phytochemical analysis revealed the presence of carbohydrates and alkaloids in all parts, and flavonoids, steroids, saponins and tannins were present in some parts.

Key words: Antibacterial activity, Phoenix dactylifera, disc diffusion assay, extracts, inhibition zone.