title: Antioxidant, antimicrobial and antiverotoxic potentials of extracts of Curtisia dentata.
abstract: BACKGROUND
  There is an increase in antimicrobial resistance and complexities arising from verotoxic related bacterial infections as well as rise in demand for application of natural antioxidants to combat oxidative damage by free radicals in many oxidative stress-mediated disease conditions such as cancer. Thus the potential of Curtisia dentata as antimicrobial, antioxidant and antiverotoxin against environmental isolates of Escherichia coli and Acinetobacter spp. as well as the presence of phytochemicals and some organic compounds, was determined.
  
  
  METHODS
  Phytochemical analysis was carried out using standard methods and antioxidant activity was determined using the DPPH radical scavenging activity. Effect of extracts on bacterial cell wall was also determined.
  
  
  RESULTS
  Extracts contained anthraquinones, alkaloids, essential oils, glycosides, phenols, steroids, saponins, tannins, quinones, anthocyanins, amines and carboxylic acids as phytochemicals. Extracts demonstrated high antimicrobial activity and low minimum inhibitory concentrations as well as inhibitory action against the expression of both Vtx1 and Vtx2 genes in Escherichia coli, Acinetobacter haemolyticus and Acinetobacter lwoffii. Ethanol root bark extracts consistently showed the highest DPPH radical scavenging activity (62.43%), total phenol content (TPH) (57.62 26 mg GAE/g) and reducing power (RP) (41.32%), followed by those of the stem bark and leaf extracts with the respective values of 54.68%, 37.77 mg GAE/g and 21.83%. The extracts induced the leakage of Na(+) and K(+) ions from both test bacteria.
  
  
  CONCLUSIONS
  Curtisia dentata is a very effective source of antioxidant and a possible alternative to sourcing antiverotoxic antibiotics with novel mechanism of action.
authors.affiliation: Faculty of Applied Sciences, Cape Peninsula University of Technology, P.O. Box 652, Cape Town 8000, South Africa. jameshamuel@yahoo.com
authors.forename: James Hamuel
authors.initials: JH
authors.lastname: Doughari
authors.forename: Patrick Alois
authors.initials: PA
authors.lastname: Ndakidemi
authors.forename: Izanne Susan
authors.initials: IS
authors.lastname: Human
authors.forename: Spinney
authors.initials: S
authors.lastname: Benade
mesh_terms: D000150:Acinetobacter / Q000187:drug effects / Q000378:metabolism; D000890:Anti-Infective Agents / Q000032:analysis / Q000494:pharmacology*; D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D000992:Antitoxins / Q000032:analysis / Q000494:pharmacology*; D029767:Cornaceae; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D022603:Shiga Toxins / Q000378:metabolism; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D000975:Antioxidants; D000992:Antitoxins; D010936:Plant Extracts; D022603:Shiga Toxins; D001618:beta-Lactamases