title: Antinociceptive effects of the aqueous and methanol extracts of the leaves of Pittosporum mannii Hook. F. (Pittosporaceae) in mice.
abstract: BACKGROUND
  Pittosporum mannii (Pittosporaceae) is used in Africa traditional medicine to treat various ailments including pain and inflammation.
  
  
  OBJECTIVE
  The present work was undertaken to evaluate the antinociceptive effects of the aqueous (AEPM) and methanol (MEPM) extracts from the leaves of Pittosporum mannii.
  
  
  METHODS
  High performance liquid chromatography coupled with mass spectrometry (LCMS) was used for the phytochemical analysis of AEPM prepared as decoction and MEPM prepared as cold maceration. The in vitro cytotoxicity of AEPM and MEPM were evaluated on Artemia salina larvae. AEPM and MEPM antinociceptive effects were evaluated at the doses of 35, 75, 150 and 300mg/kg given orally, against pain induced by acetic acid, formalin, hot plate, capsaicin and glutamate. The rota rod test was also performed at the same doses. To determine the mechanism of action of these extracts, their antinociceptive effects were tested in animals pretreated with yohimbine (α2-adrenergic antagonist), atropine (muscarinic antagonist) or naloxone (an opioids antagonist).
  
  
  RESULTS
  The LCMS analysis showed that both extracts contain pittovidoside and 1-O-rhamnopyranosyl-23-acetoxyimberbic acid 29-methyl ester, the aqueous extract being more concentrated. Oral administration of both extracts significantly reduced pain symptoms induced by acetic acid, formalin, capsaicin, glutamate and hot plate. The antinociceptive effect of AEPM was significantly inhibited by yohimbine, atropine and naloxone while these inhibitors tend to potentiate the activity of MEPM. Both extracts have no effect on Rota rod test. AEPM and MEPM showed respective LC50 of 2.44 and 0.70mg/ml on Artemia larvae and were therefore, considered non-toxic.
  
  
  CONCLUSIONS
  These results indicate that AEPM and MEPM possesses analgesic effects with different mechanism of action. Although effects of both extracts may involve TRPV1 receptors and glutamatergic pathway, AEPM may in addition, interact with alpha-adrenergic, muscarinic and opioidergic pathways that are not involve in the effects of MEPM.
authors.affiliation: Laboratory of Animal Physiology and Phytopharmacology, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Bibiane Aimée
authors.initials: BA
authors.lastname: Wandji
authors.affiliation: Laboratory of Animal Physiology and Phytopharmacology, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Francis Desire
authors.initials: FD
authors.lastname: Tatsinkou Bomba
authors.affiliation: Laboratory of Natural Products Chemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Maurice Ducret
authors.initials: MD
authors.lastname: Awouafack
authors.affiliation: Laboratory of Applied and Environmental Chemistry, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Pepin Alango
authors.initials: PA
authors.lastname: Nkeng-Efouet
authors.affiliation: Laboratory of Animal Physiology and Phytopharmacology, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Albert
authors.initials: A
authors.lastname: Kamanyi
authors.affiliation: Laboratory of Animal Physiology and Phytopharmacology, University of Dschang, P.O. Box 67, Dschang, Cameroon. Electronic address: nguelefack@yahoo.fr.
authors.forename: Télesphore Benoît
authors.initials: TB
authors.lastname: Nguelefack
mesh_terms: D019342:Acetic Acid; D000700:Analgesics / Q000737:chemistry / Q000627:therapeutic use* / Q000633:toxicity; D000818:Animals; D001156:Artemia / Q000187:drug effects; D002211:Capsaicin; D005260:Female; D005557:Formaldehyde; D018698:Glutamic Acid; D006358:Hot Temperature; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D008297:Male; D000432:Methanol / Q000737:chemistry; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D064209:Phytochemicals / Q000032:analysis / Q000627:therapeutic use / Q000633:toxicity; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000627:therapeutic use* / Q000633:toxicity; D018515:Plant Leaves / Q000737:chemistry; D019685:Rosales; D045442:Rotarod Performance Test; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000700:Analgesics; D064209:Phytochemicals; D010936:Plant Extracts; D012997:Solvents; D014867:Water; D005557:Formaldehyde; D018698:Glutamic Acid; D019342:Acetic Acid; D002211:Capsaicin; D000432:Methanol
keywords: Antinociception; Aqueous and methanol extracts; Cytotoxicity; LCMS; Pittosporum mannii