title: Characterization of n-Hexane sub-fraction of Bridelia micrantha (Berth) and its antimycobacterium activity.
abstract: BACKGROUND
  Tuberculosis, caused by Mycobacterium tuberculosis (MTB), is the most notified disease in the world. Development of resistance to first line drugs by MTB is a public health concern. As a result, there is the search for new and novel sources of antimycobacterial drugs for example from medicinal plants. In this study we determined the in vitro antimycobacterial activity of n-Hexane sub-fraction from Bridelia micrantha (Berth) against MTB H37Ra and a clinical isolate resistant to all five first-line antituberculosis drugs.
  
  
  METHODS
  The antimycobacterial activity of the n-Hexane sub-fraction of ethyl acetate fractions from acetone extracts of B. micrantha barks was evaluated using the resazurin microplate assay against two MTB isolates. Bioassay-guided fractionation of the ethyl acetate fraction was performed using 100% n-Hexane and Chloroform/Methanol (99:1) as solvents in order of increasing polarity by column chromatography and Resazurin microtiter plate assay for susceptibility tests.
  
  
  RESULTS
  The n-Hexane fraction showed 20% inhibition of MTB H37Ra and almost 35% inhibition of an MTB isolate resistant to all first-line drugs at 10 μg/mL. GC/MS analysis of the fraction resulted in the identification of twenty-four constituents representing 60.5% of the fraction. Some of the 24 compounds detected included Benzene, 1.3-bis (3-phenoxyphenoxy (13.51%), 2-pinen-4-one (10.03%), N(b)-benzyl-14-(carboxymethyl) (6.35%) and the least detected compound was linalool (0.2%).
  
  
  CONCLUSIONS
  The results show that the n-Hexane fraction of B. micrantha has antimycobacterial activity.
authors.affiliation: AIDS Virus Research Laboratory, Department of Microbiology, University of Venda, Thohoyandou 0950, South Africa.
authors.forename: Ezekiel
authors.initials: E
authors.lastname: Green
authors.forename: Lawrence C
authors.initials: LC
authors.lastname: Obi
authors.forename: Amidou
authors.initials: A
authors.lastname: Samie
authors.forename: Pascal O
authors.initials: PO
authors.lastname: Bessong
authors.forename: Roland N
authors.initials: RN
authors.lastname: Ndip
mesh_terms: D000995:Antitubercular Agents / Q000302:isolation & purification / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D019665:Euphorbiaceae / Q000737:chemistry*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy*
chemical_list: D000995:Antitubercular Agents; D010936:Plant Extracts