Phytochemical screening and antibacterial activity of selected medicinal plants against laboratory diarrheal bacteria strains

Abstract

Diarrheal diseases are major causes of mobility and mortality especially among children in developing countries. This study aimed at investigating the antibacterial activity of organic and aqueous medicinal plant extracts against diarrhea causing bacteria strains. The plant extracts were screened for the presence of phytochemical compounds by thin layer chromatography. In-vitro antibacterial activity was determined against E. coli, Shigella bodyii, Staphylococcus aureus, Salmonella typhi and Listeria monocytogenes by disc diffusion method on Mueller- Hinton agar plates; the Minimum inhibitory concentration was determined using Nutrient broth. Phytochemical screening revealed the presence of triterpernoids, saponins coumarins and alkaloids in all organic extracts and higher presence of tannins and saponins in aqueous extracts. The organic and aqueous extracts of T. sericea showed broad spectrum antibacterial activity against different diarrheal bacteria. S. linnaeanum showed the highest antimicrobial activity against Listeria monocytogenes with a concentration dependent effect. T. sericea and C. apiculatum portrayed the lowest Minimum inhibitory concentration of 62.5 µg/ml against S. aureus and E. coli.