In Vitro antibacterial activity of Yemeni medicinal plants (Ocimum basilicum and Peganum harmala) against some human pathogenic bacteria

Abstract

This study aims to evaluate the antimicrobial potential of ethanolic and water extracts of Ocimum basilicum and Peganum harmala cultivated in Yemen against some pathogenic bacteria (Escherichia coli, Kebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus). The antimicrobial activities and minimum inhibitory concentrations (MIC) of the plant extracts have been determined using Agar well diffusion method. The activity was expressed as inhibition zone diameter (IZD). A significant difference was noticed in the antibacterial activities and in the values of MIC at a significant level of α = 0.05. The aqueous extract of O. basilicum caused the highest IZD (2.2± 0.28 cm) against E. coli at 20%, whereas for alcoholic extract, the highest IZD (2.90 ± 1.27 cm) was achieved against K. pneumoniae at the same concentration. The increasing of aqueous and alcoholic extract concentration reduces the ability of the solvent to extract the active compounds from plants and weakens their inhibitory effect. The MIC values were varied depending on the source of extract, the type of bacteria and the type of solvent. In conclusion, the plant extracts used in this work could be of great value as natural antimicrobials. Further studies are needed to develop new alternative pharmacological possibilities for applications.