title: The anti-inflammatory and antioxidant activity of 25 plant species used traditionally to treat pain in southern African.
abstract: BACKGROUND
  Inflammation is a common risk factor in the pathogenesis of conditions such as infections, arthritis, type 2 diabetes mellitus, obesity and cancer. An ethnobotanical survey of medicinal plants used traditionally to treat inflammation and related disorders such as pain, arthritis and stomach aches in southern Africa led to the selection of 25 plant species used in this study.
  
  
  METHODS
  The antioxidant activities of acetone extracts were determined by measuring the free radical scavenging activity and ferric reducing ability, respectively. The anti-inflammatory activities of the extracts were determined by measuring the inhibitory effect of the extracts on the activities of the pro-inflammatory enzyme, lipoxygenase and inducible nitric oxide synthase.
  
  
  RESULTS
  Extracts of Peltophorum africanum had good antioxidant activity with IC50 values of 4.67 ± 0.31 μg/mL and 7.71 ± 0.36 μg/mL compared to that of the positive control ascorbic acid (2.92 ± 0.14 μg/mL and 13.57 ± 0.44 μg/mL), using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulphonic acid (ABTS) methods, respectively. The metabolism of linoleic acid to leukotriene derivatives by 15-lipoxygenase (15-LOX) was also inhibited by the crude acetone extracts of Peltophorum africanum (IC50 = 12.42 μg/mL), Zanthoxylum capense (IC50 = 14.92 μg/mL) compared to the positive control quercetin (IC50 = 8.75 μg/mL). There was a poor correlation between the flavonoid content and 15-LOX inhibition by the extracts (R(2) = 0.05), indicating that flavonoids are not involved in LOX inhibition. Extracts of Clausena anisata, at a concentration of 6.25 μg/mL inhibited nitric oxide production by RAW 264.7 macrophage cell lines in vitro by 96 %. The extracts of Zanthoxylum capense were the least cytotoxic (IC50 > 1000 μg/mL) when the extract toxicity was determined against Vero (African green Monkey) kidney cell lines.
  
  
  CONCLUSIONS
  Some plant species used traditionally to treat pain have reasonable anti-inflammatory activity and flavonoids are probably not involved in this process.
authors.affiliation: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria, 0110, South Africa. adebayosa@tut.ac.za.|Dept of Biomedical Sciences, Faculty of Science, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa. adebayosa@tut.ac.za.
authors.forename: Salmon A
authors.initials: SA
authors.lastname: Adebayo
authors.affiliation: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria, 0110, South Africa. jpdzoyem@yahoo.fr.|Department of Biochemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon. jpdzoyem@yahoo.fr.
authors.forename: Jean P
authors.initials: JP
authors.lastname: Dzoyem
authors.affiliation: Dept of Biomedical Sciences, Faculty of Science, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa. ShaiLJ@tut.ac.za.
authors.forename: Leshweni J
authors.initials: LJ
authors.lastname: Shai
authors.affiliation: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria, 0110, South Africa. kobus.eloff@up.ac.za.
authors.forename: Jacobus N
authors.initials: JN
authors.lastname: Eloff
mesh_terms: D000353:Africa, Southern; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D001093:Arachidonate 15-Lipoxygenase / Q000378:metabolism; D001713:Biphenyl Compounds / Q000378:metabolism; D002522:Chlorocebus aethiops; D054700:Clausena; D007887:Fabaceae / Q000737:chemistry*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D016488:Medicine, African Traditional; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D010084:Oxidation-Reduction; D010146:Pain / Q000188:drug therapy / Q000378:metabolism; D008517:Phytotherapy; D010851:Picrates / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D027821:Rutaceae / Q000737:chemistry*; D014709:Vero Cells; D032106:Zanthoxylum
chemical_list: D000700:Analgesics; D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D001713:Biphenyl Compounds; D016859:Lipoxygenase Inhibitors; D010851:Picrates; D010936:Plant Extracts; D009569:Nitric Oxide; C004931:1,1-diphenyl-2-picrylhydrazyl; D001093:Arachidonate 15-Lipoxygenase