title: Biocidal effects of stem bark extract of Chrysophyllum albidium G. Don on vancomycin-resistant Staphylococcus aureus.
abstract: BACKGROUND
  Staphylococcus aureus causes variety of infections in humans and animals worldwide and predominates in surgical wound infections. This study assessed the antimicrobial potential of the stem bark extract of Chrysophyllum albidum against an array of vancomycin resistant Staphylococcus aureus (VRSA) isolated from clinical samples.
  
  
  METHODS
  The methanolic crude extract of the plant was preliminary screened for the presence of phytochemicals; after then, the extract was partitioned into n-hexane, chloroform, ethyl acetate and butanol fractions. A range of concentrations of the plant extract fractions was prepared to assess its antimicrobial potency; the minimum inhibitory concentrations (MICs); the minimum bactericidal concentrations (MBCs); the rate of killing; the potassium ion leakage potential and nucleotides leakage ability against the VRSAs.
  
  
  RESULTS
  The phytochemical screening revealed the presence of tannins, alkaloids, flavonoids, saponins, steroids, reducing sugars and terpenoids as major phytoconstituents resident in the crude plant extract. The two active fractions (n-hexane and butanol) at a concentration of 10 mg/ml exhibited antibacterial activities with the MIC and MBC values for the fractions ranged between 0.63-10 mg/ml and 1.25-10 mg/ml respectively. The time kill assay revealed that the antibacterial action of the two fractions are time and concentration dependent; the n-hexane and butanol fractions achieved 100 % kill on the test isolates at a concentration of 3 × MIC and 2 × MIC respectively after 120 min of reaction time. Varying amount of potassium ions as well as nucleotides were leaked from the test cells by n-hexane and butanol fractions.
  
  
  CONCLUSIONS
  This study has established the possibility of developing antimicrobial agents of natural origin to manage possible infection from vancomycin resistant Staphylococcus aureus that are now developing multi-resistance against many antibiotics.
authors.affiliation: Department of Microbiology, Obafemi Awolowo University, Ile Ife, Osun State, Nigeria.|GI Microbiology and Biotechnology Unit, Agricultural Research Council, Animal Production Institute, Irene, Pretoria, 0062, South Africa.|Plant Science Department, University of the Free State, Qwaqwa Campus, South Africa.
authors.forename: David A
authors.initials: DA
authors.lastname: Akinpelu
authors.affiliation: Department of Microbiology, Obafemi Awolowo University, Ile Ife, Osun State, Nigeria.
authors.forename: Joseph O
authors.initials: JO
authors.lastname: Odewade
authors.affiliation: GI Microbiology and Biotechnology Unit, Agricultural Research Council, Animal Production Institute, Irene, Pretoria, 0062, South Africa. Aiyegoroo@arc.agric.za.|Plant Science Department, University of the Free State, Qwaqwa Campus, South Africa. Aiyegoroo@arc.agric.za.
authors.forename: Olayinka A
authors.identifier: http://orcid.org/0000-0001-6664-6574
authors.initials: OA
authors.lastname: Aiyegoro
authors.affiliation: Plant Science Department, University of the Free State, Qwaqwa Campus, South Africa.
authors.forename: Anofi O T
authors.initials: AO
authors.lastname: Ashafa
authors.affiliation: Department of Biological Science, Faculty of Agriculture and Biotechnology, North West University, Mahikeng Campus, Mmabatho, 2735, South Africa.
authors.forename: Oluseun F
authors.initials: OF
authors.lastname: Akinpelu
authors.affiliation: Plant Science Department, University of the Free State, Qwaqwa Campus, South Africa.
authors.forename: Mayowa O
authors.initials: MO
authors.lastname: Agunbiade
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D008826:Microbial Sensitivity Tests; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology*; D018547:Plant Stems / Q000737:chemistry; D029632:Sapotaceae / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D014640:Vancomycin
keywords: Chrysophyllum albidum; Clinical samples; Methanolic extract; Minimum bactericidal concentrations; Minimum inhibitory concentrations; Nucleotide; Phytochemicals; Potassium ion; Time kill; Vancomycin resistant Staphylococcus aureus