title: Antibacterial activity of aqueous and methanol extracts of selected species used in livestock health management.
abstract: BACKGROUND
  Salvadora persica L. (Salvadoraceae), Colophospermum mopane (J.Kirk ex Benth.) J. Léonard (Leguminosae) and Dichrostachys cinerea (L.) Wight & Arn. (Leguminosae) crude extracts are used by local farmers against many livestock infections with little or no side effects usually associated with synthetic antimicrobials. However, their efficacy has rarely been tested.
  
  
  OBJECTIVE
  These plants were tested for potential antibacterial activity against clinical isolates of Staphylococcus aureus ATCC33862 and Escherichia coli ATCC25922. Minimal inhibitory concentrations (MIC) of the crude plant extracts were determined.
  
  
  METHODS
  Aqueous and methanol extraction of 100 g each of the bark of C. mopane, roots of D. cinerea and leaves of S. persica was done by placing the samples in 250 mL of either water or methanol. Nutrient broth was used as growth medium for the bacteria, and McFarland standard for bacterial standardization. 2,3,5-Triphenyltetrazoliumchloride (TTC) was the indicator salt. Each of the aqueous and methanol extracts (100 μL) was tested. Gentamycin and ampicillin were the controls.
  
  
  RESULTS
  MIC of aqueous extracts ranged from 1.03-14.6 mg/mL against S. aureus, and from 12.1-34.3 mg/mL against E. coli. Methanol extracts ranged between 5.31 and 9.64 mg/mL against S. aureus, and between 7.86 and 13.6 mg/mL against E. coli. Aqueous and methanol extracts of S. persica were significantly higher (p < 0.05) than C. mopane and D. cinerea.
  
  
  CONCLUSIONS
  Colophospermum mopane, S. persica and D. cinerea exhibited antibacterial activity, with methanol extracts performing better than aqueous extracts, justifying use as ethnoveterinary medicine. Further study to isolate the active components should be pursued.
authors.affiliation: a Department of Geography and Environmental Science , University of Zimbabwe , Harare , Zimbabwe.|b Department of Research and Specialist Services, Division of Livestock Research , Grasslands Research Institute , Marondera , Zimbabwe.
authors.forename: Clarice P
authors.initials: CP
authors.lastname: Mudzengi
authors.affiliation: a Department of Geography and Environmental Science , University of Zimbabwe , Harare , Zimbabwe.
authors.forename: Amon
authors.initials: A
authors.lastname: Murwira
authors.affiliation: c Department of Veterinary Science , University of Zimbabwe , Harare , Zimbabwe.
authors.forename: Musa
authors.initials: M
authors.lastname: Tivapasi
authors.affiliation: d Department of Animal Production and Technology , School of Agricultural Sciences and Technology, Chinhoyi University of Technology , Chinhoyi , Zimbabwe.
authors.forename: Chrispen
authors.initials: C
authors.lastname: Murungweni
authors.affiliation: e Department of Livestock and Veterinary Services, Division of Veterinary Services , Harare , Zimbabwe.
authors.forename: Joan V
authors.initials: JV
authors.lastname: Burumu
authors.affiliation: f Department of Animal Science , University of Zimbabwe , Harare , Zimbabwe.
authors.forename: Tinyiko
authors.initials: T
authors.lastname: Halimani
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D058751:Livestock; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D014730:Veterinary Medicine
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts
keywords: Ethnoveterinary medicine; Staphylococcus aureus; Escherichia coli; minimum inhibitory concentration