title: Polyphenol-rich fraction of Parquetina nigrescens mitigates dichlorvos-induced neurotoxicity and apoptosis.
abstract: BACKGROUND
  Parquetina nigrescens (Afzel.) Bullock of the family Asclepiadaceae is known for its antioxidant effects with wide range of uses in Southwestern Nigeria especially in traditional medicine. This study was undertaken to explore if polyphenol-rich fraction (prf) from P. nigrescens will ameliorate dichlorvos-induced neurotoxicity and apoptosis. The exploration utilized evaluation of markers of oxidative stress, apoptosis and serum acetylcholinesterase (AchE) levels.
  
  
  METHODS
  Forty Wistar rats randomly placed in four groups were utilized for the study. Animals in Group A received corn oil, group B- dichlorvos (16 mg/kg), groups C and D- dichlorvos + 100 and 200 mg/kg prf of P. nigrescens respectively. Markers of oxidative stress, antioxidants and apoptosis were assessed in the serum and brain tissues using biochemical assay and immunohistochemistry.
  
  
  RESULTS
  Exposure to dichlorvos caused significant decreases in AchE, catalase, superoxide dismutase, glutathione peroxidase (GPx) and increases in hydrogen peroxide (H2O2) generation and malondialdehyde levels. Histopathology and immunohistochemistry of the cerebellum and cerebrum of rats exposed to dichlorvos revealed greater neurotoxic effects in the cerebellum as well as decreased expressions of AchE with a concomitant increase in Bax (proapototic) compared to prf of P. nigrescens treated rats.
  
  
  CONCLUSIONS
  This study showed that dichlorvos caused cellular and tissue neurotoxicity by inhibiting AchE activity, induced oxidative stress and apoptosis in rats with prominent effects on the cerebellum than cerebrum. The prf of P. nigrescens showed amelioration of neurotoxicity by its antioxidative and antiapoptotic properties in rats exposed to dichlorvos.
authors.affiliation: Department of Veterinary Physiology, Biochemistry and Pharmacology, Faculty of Veterinary Medicine, University of Ibadan, Nigeria.
authors.forename: Grace Onyeche
authors.initials: GO
authors.lastname: Ochigbo
authors.affiliation: Department of Veterinary Physiology, Biochemistry and Pharmacology, Faculty of Veterinary Medicine, University of Ibadan, Nigeria.
authors.forename: Adebowale Bernard
authors.initials: AB
authors.lastname: Saba
authors.affiliation: Department of Veterinary Physiology, Biochemistry and Pharmacology, Faculty of Veterinary Medicine, University of Ibadan, Nigeria. Electronic address: aa.oyagbemi@ui.edu.ng.
authors.forename: Ademola Adetokunbo
authors.initials: AA
authors.lastname: Oyagbemi
authors.affiliation: Department of Veterinary Medicine, Faculty of Veterinary Medicine, University of Ibadan, Nigeria.
authors.forename: Temidayo Olutayo
authors.initials: TO
authors.lastname: Omobowale
authors.affiliation: Department of Veterinary Biochemistry, Faculty of Veterinary Medicine, University of Benin, Nigeria.
authors.forename: Ebunoluwa Racheal
authors.initials: ER
authors.lastname: Asenuga
keywords: Acetylcholinesterase; Antioxidant; Apoptosis; Dichlorvos; Parquetina nigrescens