title: Effects of kolaviron on hepatic oxidative stress in streptozotocin induced diabetes.
abstract: BACKGROUND
  Alteration in antioxidant defence and increase in oxidative stress that results in tissue injury is characteristic of diabetes. We evaluated the protective effects of kolaviron (a flavonoid complex extracted from the seeds of Garcinia kola) on hepatic antioxidants, lipid peroxidation and apoptosis in diabetic rats.
  
  
  METHODS
  To induce diabetes, rats were injected with streptozotocin intraperitoneally at a single dose of 50 mg/kg. Kolaviron (100 mg/kg) was administered orally for 6 weeks (5 times weekly). Activities of liver antioxidant enzymes was analysed with Multiskan Spectrum plate reader. High performance liquid chromatography (HPLC) was used in the analysis of MDA (malondialdehyde), a product of lipid peroxidation. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.
  
  
  RESULTS
  Diabetic rats exhibited a significant increase in the peroxidation of hepatic lipids as observed from the elevated level of malondialdehyde (MDA). In addition, Oxygen Radical Absorbance Capacity (ORAC), level of reduced glutathione (GSH), ratio of reduced to oxidized glutathione (GSH: GSSG) and catalase (CAT) activity were decreased in the liver of diabetic rats. The activities of GPX (glutathione peroxidase) and SOD (superoxide dismutase) were unaltered in diabetic rats. TUNEL assay revealed increased apoptotic cell death in the liver. Kolaviron attenuated lipid peroxidation and apoptosis, increased CAT activity, GSH levels and GSH: GSSG ratio. The ORAC of kolaviron-treated diabetic liver was restored to near-normal values.
  
  
  CONCLUSIONS
  Kolaviron protects the liver against oxidative and apoptotic damage induced by hyperglycemia.
authors.affiliation: Department of Biochemistry, Bowen University, Iwo, Nigeria.
authors.forename: Omolola R
authors.initials: OR
authors.lastname: Oyenihi
authors.affiliation: Department of Wellness Sciences, Cape Peninsula University of Technology, Cape Town, South Africa.
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Brooks
authors.affiliation: Nutrition and Chronic Diseases Unit, Oxidative Stress Research Centre, Department of Biomedical Sciences, Cape Peninsula University of Technology, Bellville, South Africa. oguntibejuo@cput.ac.za.
authors.forename: Oluwafemi O
authors.initials: OO
authors.lastname: Oguntibeju
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D002374:Catalase / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005419:Flavonoids / Q000494:pharmacology / Q000627:therapeutic use*; D029763:Garcinia kola / Q000737:chemistry*; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D006943:Hyperglycemia / Q000188:drug therapy; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D012639:Seeds / Q000737:chemistry; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010936:Plant Extracts; D008315:Malondialdehyde; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione; C045492:kolaviron