title: Studies on the biocidal and cell membrane disruption potentials of stem bark extracts of Afzelia africana (Smith).
abstract: We had recently reported antibacterial activity in the crude extract of the stem bark of Afzelia africana (Akinpelu et al., 2008). In this study, we assessed the biocidal and cell membrane disruption potentials of fractions obtained from the crude extract of the plant. The aqueous (AQ) and butanol (BL) fractions exhibited appreciable antibacterial activities against the test bacteria. The minimum inhibitory concentrations of the AQ and BL fractions ranged between 0.313 and 2.5 mg/ml, while their minimum bactericidal concentrations varied between 0.625 and 5.0 mg/ml. Also, the AQ fraction killed about 95.8% of E. coli cells within 105 min at a concentration of 5 mg/ml, while about 99.1% of Bacillus pumilus cells were killed by this fraction at the same concentration and exposure time. A similar trend was observed for the BL fraction. At a concentration of 5 mg/ml, the butanol fraction leaked 9.8 microg/ml of proteins from E. coli cells within 3 h, while the aqueous fraction leaked 6.5 microg/ml of proteins from the same organisms at the same concentration and exposure time. We propose that the stem bark of Afzelia africana is a potential source of bioactive compounds of importance to the pharmaceutical industry.
authors.affiliation: Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa.
authors.forename: David A
authors.initials: DA
authors.lastname: Akinpelu
authors.forename: Ayobami O
authors.initials: AO
authors.lastname: Aiyegoro
authors.forename: Anthony I
authors.initials: AI
authors.lastname: Okoh
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D007887:Fabaceae / Q000737:chemistry*; D006090:Gram-Negative Bacteria / Q000166:cytology / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000166:cytology / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts