title: Evaluation of the in vitro antibacterial activity of the solvent fractions of the leaves of Rhamnus prinoides L'Herit (Rhamnaceae) against pathogenic bacteria.
abstract: BACKGROUND
  Medicinal plants play great roles in the treatment of various infectious diseases. Rhamnus prinoides is one of the medicinal plants used traditionally for treatment of bacterial diseases. The antibacterial activity of the crude extract of the plant had been shown by a previous study, but this study was undertaken to further the claimed medicinal use of the plant by screening its solvent fractions for the said activity so that it could serve as a basis for subsequent studies.
  
  
  METHODS
  The solvent fractions of the plant were obtained by successive soxhlet extraction with solvents of increasing polarity, with chloroform and methanol, followed by maceration of the marc of methanol fraction with water. The antibacterial activity of the solvent fractions was evaluated on seven bacterial species using agar well diffusion method at different concentrations (78 mg/well, 39 mg/well and 19.5 mg/well) in the presence of positive and negative controls. The minimum inhibitory concentration of the solvent fractions was determined by micro-broth dilution method using resazurin as indicator.
  
  
  RESULTS
  Methanol and chloroform fractions revealed antibacterial activities against the growth of test bacterial strains with varying antibacterial spectrum and the susceptible bacterial species were Staphylococcus aureus, Streptococcus pyogen, Streptococcus pneumoniae and Salmonella typhi. The average minimum inhibitory concentration value of the methanol and chloroform fractions ranged from 8.13 mg/ml to 32.5 mg/ml and from 8.13 mg/ml to 16.25 mg/ml, respectively.
  
  
  CONCLUSIONS
  The methanol and chloroform fractions demonstrated significant antibacterial activities against the growth of pathogenic bacteria but the aqueous fraction did not reveal antibacterial activity against any of the test bacteria.
authors.affiliation: Department of Pharmacy, College of Health Sciences, Debre Markos University, P. O. Box, 269, Debre Markos, Ethiopia.
authors.forename: Yalew
authors.initials: Y
authors.lastname: Molla
authors.affiliation: Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, Addis Ababa University, P. O. Box, 1176, Addis Ababa, Ethiopia.
authors.forename: Teshome
authors.initials: T
authors.lastname: Nedi
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine and Agriculture, Addis Ababa University, P. O. Box, 1176, Addis Ababa, Ethiopia.
authors.forename: Getachew
authors.initials: G
authors.lastname: Tadesse
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P. O. Box, 1176, Addis Ababa, Ethiopia.
authors.forename: Haile
authors.initials: H
authors.lastname: Alemayehu
authors.affiliation: Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, Addis Ababa University, P. O. Box, 1176, Addis Ababa, Ethiopia. workineh.shibeshi@aau.edu.et.
authors.forename: Workineh
authors.initials: W
authors.lastname: Shibeshi
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002725:Chloroform; D000432:Methanol; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D031955:Rhamnus / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D002725:Chloroform; D000432:Methanol
keywords: Antibacterial activity; Minimum inhibitory concentration; Salmonella typhi; Staphylococcus aureus; Streptococcus pneumoniae; Streptococcus pyogen