title: Antibacterial activity of extracts of three Croton species collected in Mpumalanga region in South Africa.
abstract: The antibacterial activities of three Croton species were compared using bioautography and the serial microdilution methods. The methanolic extracts of all the species had low activity against Escherichia coli. The highest activity was observed with Croton megalobotrys against Enterococcus faecalis with a minimal inhibitory concentration (MIC) value of 0.02 mg/ml. Croton steenkapianus extracts were the least active of the species investigated, only managing an MIC value of 0.625 mg/ml against Pseudomonas aeruginosa. Croton megalobotrys leaf powder was serially extracted using solvents of various polarities. The lowest MIC value (0.06 mg/ml) of the serially extracted fractions was observed with acetone against Pseudomonas aeruginosa. The liquid-liquid fractions of the methanol extract of Croton megalobotrys were also tested. The lowest MIC value of 0.02 mg/ml was observed with n-hexane fraction against Enterococcus faecalis. The carbon tetrachloride fraction was further fractionated using column chromatography with silica as the immobile phase. The resulting seven fractions were tested for activity following the bioassay-guided practice, and it emerged that the first three fractions had active compounds against Staphylococcus aureus when the bioautography method was used.
authors.affiliation: Department of Biochemistry, University of Limpopo, Medunsa, South Africa.
authors.forename: S C
authors.initials: SC
authors.lastname: Selowa
authors.forename: L J
authors.initials: LJ
authors.lastname: Shai
authors.forename: P
authors.initials: P
authors.lastname: Masoko
authors.forename: M P
authors.initials: MP
authors.lastname: Mokgotho
authors.forename: S R
authors.initials: SR
authors.lastname: Magano
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D029802:Croton / Q000737:chemistry* / Q000145:classification; D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D000432:Methanol; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013019:South Africa; D013211:Staphylococcus aureus / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D000432:Methanol