Antibacterial Activity and Chemical Composition of Crude Extract and Oil of Zygophyllum (Fagonia) luntii (Baker) 1894 (Family Zygophyllaceae)

Wild plants such as Zygophyllum luntii, from the Zygophyllaceae family, have traditionally been used for medicinal purposes in Oman. The present study investigated (i) the antibacterial activity of the crude extracts (leaves, stem and roots) and the oil (leaves); and (ii) the hydrocarbon contents and fatty acid methyl ester (FAME) components from Z. luntii. These extracts were tested against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa using well diffusion assays utilizing Muller Hinton Agar (MHA). Antibacterial activity was observed with the Z. luntii leaf extract and significant differences (F=14.06, df=2, P=0.002) were found among E. coli, P. aeruginosa and S. aureus. The highest inhibition was observed against P. aeruginosa, with an inhibition zone of 15.5 ± 2.6 mm, followed by E. coli and S. aureus with inhibition zones of 11.3 ± 1.5 mm and 3.5 ± 4.7 mm, respectively. The Z. luntii extracts showed effectiveness within 50-60% against E. coli and P. aeruginosa as compared to Ciprofloxacin. The hydrocarbon contents and the FAME components of the extracts were determined with Gas Chromatography-Mass Spectrometry (GC-MS). A total of 20, 19, and 8 compounds were detected from leaf, stem, and root extracts, respectively. Heneicosane, docosane, and tricosane were found in the highest concentration in the leaves, HOP-22(29)-EN-3.BETA.-OL and β-sitosterol were found in the stems, and docosane and tricosane were found in the roots of Z. luntii. Nine types of fatty acids methyl esters were detected in the oil extracted from leaves with methyl esters of palmitic acid, linolenic acid, and oleic acid constituting 90% of the oil. This is the first report on antibacterial activity and chemical composition of Z. luntii.