The problem of microbial resistance continues to increase in all regions of the world, and even though a very large number of antibiotics have been produced in the last 30 years, microbial resistance is maintained because of the wide use of these drugs against many infectious diseases. Thus, natural products are seen as the alternative solution. Based on previous studies, Peganum harmala has been reported to exhibit several biological properties including antibacterial and antifungal. Thus, the main aim of this study is evaluating antibacterial activities of P. harmala against Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus, which isolated from infected patients in (Alassaba'a hospital, Alassaba'a, west of Tripoli). Agar disk diffusion technique was used for detecting the antibacterial activity, and the minimum inhibitory concentration was tested by serial dilution methods. The results showed that the growth of all tested bacteria were inhibited strongly by methanol extract of seeds at 1.0% with inhibition zones 14.66, 12.00 and 15.33mm against E. coli, k. pneumoniae and S. aureus respectively. Besides, MIC values ranged between 0.625 to 1.25 mg/mL. While, MBC values ranging between 1.25 to 5 mg/mL. On the other hand, methanol extract of leaves was also inhibit the growth of E. coli, k. pneumoniae and S. aureus with inhibition zones 11.00, 9.66 and 10.00mm respectively. As well as, MIC values ranging between 1.25 to 2.5 mg/mL, while MBCs value ranging between 2.5 to 5 mg/mL . In conclusion, methanol extract of P. harmala seeds exhibited strongly antimicrobial activity against E. coli, k. pneumoniae and S. aureus, thus it can be developed as anti-bacterial agent.

The aim of the present study was to evaluate the variations in the phytochemical compositions and the antimicrobial activities of Syzygium grande and Oenanthe javanica leaf extracts against Bacillus sp. The antibacterial activity of the methanol, 70% methanol, ethyl acetate, and hexane extracts of both plant species were examined in vitro, against various Bacillus species. In addition, the 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy-based metabolomics was employed to gain insights into the correlations between the chemical constituents of the bioactive extract to the biological activity. The hexane extract of S. grande leaves and methanolic extract of O. javanica leaves showed more potent anti Bacillus activity, among the test extracts. Principal component analysis (PCA) successfully differentiated the extracts on the basis of their metabolite profiles. The results of the Partial Least Square (PLS) analysis showed that the non-polar compounds of the hexane extract of S. grande (alanine, betulin, β-sitosterol, β-caryophyllene, acetic acid and 3-hydroxybutyric acid) were strongly correlated to its anti-Bacillus activity. On the other hand, choline, ellagic acid, and gallic acid, the metabolites present in the methanolic extract of O. javanica, were strongly correlated to its anti-Bacillus activity. On this basis, it was therefore concluded that these conmpounds could be the potential bioactive constituents, contributing to the anti-Bacillus activity of the individual plant species. Further in-depth investigations into the potential utilization of the two plants for useful applications in managing and control of Bacillus sp., will help pave the way towards their valorization.