Phytochemical diversity, classification and antibacterial activity of some medicinal plant species from tabuk (saudi arabia)

Objectives of this study were to investigate the phytochemical diversity of nine medicinal plant species from Tabuk (KSA), namely (Pulicaria undulata L., Pulicaria incisa Lam., Artemisia herba-alba Asso., Artemisia monosperma Delile, Artemisia judaica L. and Achillea fragrantissima Forssk, Ducrosia flabellifolia Boiss., Thymus vulgaris L. and Lavandula coronopifolia Poir.); to evaluate the antibacterial potentials of plant extracts, and to inspect the possible associations between phytochemical diversity and constituents with the antibacterial activities of plant extracts. GC-MS technique was used to identify phytochemicals. The standard disk diffusion technique was used to conduct the antibiotic susceptibility against four pathogenic bacterial species. 160 phytochemicals from 30 classes were identified. A. fragrantissima had the highest phytochemical diversity and P. incisa had the lowest. Ethanol outperformed other extraction solvents in  antibacterial activity, Pulicaria undulata and T. vulgaris ranked highest among plants in this regard. Gram positive bacterial species were more sensitive to plant extracts. Terpenoid and benzene showed significant (p 0.05) positive correlations with the antibacterial activity against E. coli, terpenoid contents showed positive correlation with activity against P. aeruginosa, and benzene showed positive correlation with activity against other bacterial species. Phytochemical diversity and antibacterial activity against E. coli and P. aeruginosa were positively correlated.