Antimicrobial Activity of Medicinal Plants and the Biological Effects of Selected Plants on Staphylococcus Aureus (Published)
Several natural products especially secondary metabolites have formed the basis of medicines, although it’s been often difficult to justify the presence of these compounds in the biochemistry of plant; this as posited by Cragg et al., in their presentation on Ethnobotany and the Search for New Drugs, Ciba Foundation Symposium draws a challenge to scientists. It has been suggested that these compounds may have been synthesized by the plants as part of the defense system of the plant; a good example is that plants are known to produce phytoalexins as a response to attack by bacteria and fungi. Cragg and Newmann in Biodiversity: A continuing source or novel drug leads, support this though stating that the compound produced provides an invaluable resource that has been used to find new drug molecules This paper is set to identify the antimicrobial activity of these medicinal plants and their biological effects. The sampled out plant extracts include Thymus vulgaris, Berberis vulgaris and Calluna vulgaris with which inhibition or activation by different chemical catalysts is performed to establish their effects in the tested natural extracts. Experimental design is used where the reagents are determined and chemical reactions performed in the procedures as outlined in the methodology section. The results of the microbial activity based on the level of concentration is then recorded for every crude extracts and the effects of each with different antibiotics against Staphylococcus aureus. This study reflects that berberine showed excellent synergistic activity against Staphylococcus aureus at relatively low concentration and thus can be used against staphylococcus infections
Keywords: Antimicrobial, Berberis Vulgaris, Calluna Vulgaris, Metabolites, Staphylococcus Aureus, Thymus Vulgaris
ANTIMICROBIAL POTENTIAL OF LEBANESE CEDAR EXTRACT AGAINST HUMAN PATHOGENS AND FOOD SPOILAGE MICROORGANISMS (Published)
Water and methanolic extracts of the leaves, stems, and pulp of Lebanese Cedar (Cedrus libani), were assayed for antibacterial and antifungal properties against human and food spoilage pathogens namely: Klebsiella pneumonia, MRSA, ESBL E. coli, Listeria monocytogenes, and Candida albicans using disk diffusion method. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) were evaluated. The bacterial and fungal strains tested showed a various degree of sensitivity represented by inhibition zone diameter: Klebsiella pneumonia (27mm), MRSA (27mm), ESBL Escherichia coli (20mm), and Candida albicans (21mm). Listeria monocytogenes showed the strongest inhibition zone 70 and 37mm with methanolic and water leaves extracts respectively. The MIC, MBC, and MFC were between 5- 200 µl/ml, and 300 µl/ml respectively. Time-kill curve showed a fast and sharp antimicrobial activity. The efficacy of killing by Lebanese cedar extract was essentially the same in light and dark. Phytochemical analysis of Lebanese cedar extract explored the presence of terpenoids, flavenoids, glycosides, phenols, saponins and traces of tannins. Electron microscopy examination of cells treated with Lebanese cedar extracts showed a great variation in the cell structure.
Keywords: Antimicrobial, Food Spoilage Microorganisms, Human Pathogens, Lebanese Cedar