Phytochemical analysis and antibacterial activity of Washingtonia filifera (Lindl.) H. Wendl. fruit extract from Saudi Arabia

This work aimed to assess the antimicrobial potential of Washingtonia filifera extracts on some human pathogens. Agar well diffusion and minimum inhibitory concentrations (MIC) methods have been used to assess the antimicrobial activities of W. filifera extract against Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, Escherichia coli, and Candida albicans. Only the ethyl acetate (ETAC) and methanol extracts revealed antimicrobial activity against tested microorganisms. S. aureus appears to be the most sensitive microbes to the ETAC extract with equal inhibition zone (30 mm) and MIC (65 µg/mL) values. This is followed by K. pneumoniae, E. coli, and A. baumanni, respectively. The plant extract had different phytochemical constituents such as alkaloids, sterols, and polyphenols. Column chromatography of the ETAC extract resulted in the loss of inhibitory effect at the highest concentration tested (50 mg/mL) against tested microorganisms. The haemolytic activity of the different extracts was found in the following order: Hexane (83.57%) > ETAC (35.71%) > chloroform (23.57143) > methanol (0.71%) based on the highest concentration tested (8.3 mg/mL). In conclusion, ETAC extract was the most promsing extract among extracts tested. Secondary plant metabolites are of great value as natural antimicrobial agents.