International Journal of Microbiology and Immunology Research Vol. 3(3), pp. 029-035, April 2015 ISSN 2327-7769 ©2015 Academe Research Journals

Full Length Research Paper

Antibacterial activity and phytochemical screening of some important medicinal plants against human diarrheal pathogens in Adama city, Ethiopia

H. Tesso*, A. K. Nisha and K. Kumsa

School of Natural Sciences, Adama Science and Technology University, Adama, Ethiopia.

*Corresponding author: E-mail: michaeltesso@yahoo.com. Tel: +251221110400; Fax: +251221100038.

Accepted 26 March, 2015

Abstract

The methanol and chloroform plant extracts of Withania somnifera, Azadirachta indica, Croton macrostachyus and Leonotis nepetifolia showed significant antibacterial activity against 160 clinical isolates of Salmonella and Shigella sp collected from Pediatric Division of The Adama Referral Government Hospital, Adama, Ethiopia. The stool specimens were collected from children belonging to the age group of 0-10 years. Growth inhibitions were determined using standard agar dilution method. Preliminary screening of W. somnifera, A. indica, C. macrostachyus and L. nepetifolia revealed the presence of alkaloids, glycosides, saponins, phenols, tannins, flavanoids and terpenoids in the extracts. All the four plant extracts showed antimicrobial activity against the clinical isolates tested and it increased with increasing concentrations. A. indica extract exhibited maximum inhibition on both the diarrheal pathogens tested bacterial species at a concentration of 2 mg/ml. The antibacterial and phytochemical screening insured the importance of these plant extracts and can be speculated for use in the future.

Key words: Antibacterial activities, diarrheal pathogens, phytochemical extracts, growth inhibition.