Antimicrobial effect of local medicinal plant extracts in the Kingdom of Saudi Arabia and search for their metabolites by gas chromatography-mass spectrometric (GC-MS) analysis

Abstract

The present study was designed to evaluate the anti-microbial properties of leaf extract from some local plants in Saudi Arabia belonging to seven different families which areRumex vesicarius from the family Polygonaceae, Datura stramonium from the familySolanaceae, Zygophyllum coccineum from the family Zygophyllaceae, Citrullus colocyuthus from the family Cueurbitaceae, Lasiurus scindicus from the family Poaceaeand Heliotropium digynum from the family Boraginaceae against seven human pathogenic bacteria and yeast strains including Staphylococcus aureus ATCC 25923, Bacillus subtilisATCC 6633, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853,Salmonella suis ATCC 13076, Shigella sonnei ATCC 11060, and Candida albicans ATCC 10231. The compounds were extracted using two different extraction agent water and acetone. The evaluation of the anti-microbial activities of the extracts was examined against all the aforementioned microorganisms by standard agar well diffusion method. The water extracts showed no antibacterial activities in all the different plant families, but as for the acetone's extracts, the antimicrobial activities were moderate to strong (about 18 to 30 mm). The compounds present in the extracts were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The leaf extracts of the following medicinal plants were mainly found to contain compounds like 4-ethyl-2-hydroxycyclopent-2-en-1-one, 2-methoxy-4-vinylphenol, and cyclobutanol for R. vesicarius; hexanoic, nonanoic, octanoic, and heptanoic acid for D. stramonium; 1-hexyl-2-nitrocyclexane, 2-octadecyl-propane-1,3-diol, octadecanal, and cyclohexane for Z. coccineum; l-(+)-ascorbic acid 2,6-dihexadecanoate, eicosanoic acid, and 2-heptadecenal for C. colocyuthus; butanoic acid, 6-octen-1-ol,3,7-dimethyl-propanoate, 2-hydroxy-3,5-dimethylcyclopent-2-en-1-one, and alpha-cadinol for L. scindicus; and 5H-1-pyrindine indolizine, 7-acetyl-2-hydroxy-2-methyl-5-isopropylbicyclo, 1-hexyl-2-nitrocyclohexane for H. digynum. Key words: Antimicrobial activities, medicinal plant extract, agar well diffusion method, gas chromatography-mass spectrometry (GC-MS), Saudi Arabia.