Antibacterial Activity of Rhamnus prinoides extracts against Staphylococcus aureus and Escherichia coli

Abstract Background: Infectious diseases caused by bacteria have a large impact on public health. Increasing in resistant microbial infections intensified the search for new, safer, and more efficacious agents to combat serious microbial infections. Plants have played a central part in combating many diseases in human and domestic animal in many local communities, including Africa. Rhamnus prinoides is Ethiopian medicinal plants that have been used traditionally for the treatment of diverse infectious diseases. Therefore, this research was carried out to evaluate antibacterial activity Rhamnus prinoides extracts against pathogenic bacteria. Methods: The antimicrobial activity tests were carried out by the agar well diffusion method. Broth dilution and streak plate methods were used to determine MIC and MBC of extracts respectively. Results: The results revealed that ethanol extracts of fruits showed the highest antibacterial activity against standard strains of S.aureus with mean inhibition zone of 26±0.58, 28.33±1.2 and 33.33±0.9mm at 25, 50 and 100mg/ml respectively. The lowest mean MIC value (1.04 mg/ml) was recorded with ethanol extract of fruits against standard strains of S. aureus and the lowest mean MBC value (2.08 mg/ml) was recorded with ethanol extract of fruits against standard strains and clinical isolates of S. aureu. Conclusion: On the basis of the current findings, Rhamnus prinoides could be a good candidate in the search for new antibacterial agents from natural products against bacterial pathogens. Therefore, further studies are needed to study their toxicology and isolate the bio- active components from this plant. Key words: Antibacterial activity, Escherichia coli, MBC, MIC, Rhamnus prinoides, Staphylococcus aureus