Antimicrobial activities and phytochemical analysis of leaf extracts of Echinops abuzinadianus Chaudhary growing in Abha City, Saudi Arabia

Echinops abuzinadianus belongs to the sunflower or Asteraceae family, which is widely found in an abandoned area in Abha city in Saudi Arabia. The properties of this endemic plant have not been yet researched. This study used agar well diffusion methods to investigatethe antimicrobial inhibition activity of solvent-extracted dry and fresh E. abuzinadianus leaves against some human pathogenic microbes. The results show that almost all solvent extracts had significant inhibitory activity against Shigella flexneri, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, Micrococcus luteus and Candida albicans. Fresh leaf-extract had more potent activity against all tested microorganisms than dry leaf-extract. The maximum antibacterial activity against S. Flexneri was gained from methanol extract, chloroform extracts against Pseudomonas aeruginosa, diethyl ether extracts against K. pneumoniae and acetone extract against C. albicans. Petroleum ether extract showed moderate antibacterial activities against P. mirabilis, while petroleum ether extract exhibited the minimum antibacterial activity against K. pneumonia. Gas chromatography mass spectrometry (GC-MS) showed the presence of five phytochemical compounds: palmitic acid (the most dominant compound), followed by 9-octadecenoic acid, octadecatrienoic acid, and trace quantities of octadeca-9,12,15-trienoic acid and phytol. The inhibition of the microbial growth in the presence of solvent extracts of E. abuzinadianus leaves and the secondary metabolites produced by the plants, make it a promising medicinal plant.