Evaluation for In-vitro Antibacterial Activity of Selected Medicinal Plants against Food-Borne Pathogens

Abstract

Folkloric medicinal plants are commonly used all over the world and linked with different cultural believes. In most developing countries, including Ethiopia, where many people live under poor hygienic conditions; and has low access to modern health care system, the chance infection with food borne disease is undoubtedly high. As a result, peoples visit traditional healers as an alternative to the modern health care system. To this effect, five traditional medicinal plants (Vernonia amygdalina, Nigella sativa, Ocimum sauve, Ruta graveolens and Ocimum lamifolium) were collected for evaluation of in vitro antibacterial activity. Soxhlet extraction method and agar disk diffusion techniques were used to obtain the crude extracts as well as for antibacterial activity test. All the petroleum ether, chloroform and methanol crude extracts of the five medicinal plants and volatile oil were tested against standard reference strains, including Escherichia coli (ATCC25722), Staphylococcus aureus (ATCC25903), Shigella sonnei (ATCC259131) and Salmonella typhimurium (ATCC13311). The essential oil extract of Nigella sativa seeds showed better activity against the Gram negative bacteria Salmonella typhimurium at concentration of 3.7 µl. Based on our observation, it could be concluded that the crude and volatile oil extracts of the plants are candidate products for treatment of gastrointestinal pains having gone through additional investigation on pharmacokinetics and toxicity of the extracts.