Evaluation of Tarchonanthus camphoratus plant extracts for antimicrobial activity against food-borne pathogens
Food-borne pathogens are a major cause of illness, there are about 31 different pathogens known to cause food-borne illnesses. Meat products such as poultry meat, eggs, pork and beef are amongst the most important sources of food-borne illnesses. Antibiotics have also been used in animal feed to control food-borne pathogens however, resistance, which is an inevitable consequence of antibiotic; is an increasing public health problem. Plant secondary metabolites have been shown to exhibit antimicrobial activity against pathogens that cause food-borne diseases. This study evaluated the antimicrobial properties of Tarchonanthus camphoratus, the camphor bush, against three common poultry pathogens: Salmonella typhi, Escherichia coli and Staphylococcus aureus. Aqueous and organic extracts of the plant (leaves, stems and bark) were prepared using distilled water and 80% methanol. Phytochemical analysis revealed the presence of terpenoids and glycosides in both the extracts. Organic leaf extract exhibited the highest inhibitory activity against S. typhi (0.5 mg/ml, inhibition zone 19.3 mm in diameter), S. aureus (10 mg/m, 19.7mm) and E. coli (1 mg/ml, 7.7 mm) consistent with ethnomedicinal use. However, aqueous extracts exhibited no antimicrobial activity against the test microorganisms. T. camphoratus extracts exhibited antimicrobial activity against all the three tested food borne pathogens and its use should be considered in combination with conventional antibiotics. Keywords: Tarchonanthus camphoratus, Salmonella typhi, Staphylococcus aureus, Escherichia coli, phytochemical analysis, well diffusion assays, antimicrobial activity.