title: 5-HT(3)  and 5-HT(4)  receptors contribute to the anti-motility effects of Garcinia buchananii bark extract in the guinea-pig distal colon.
abstract: BACKGROUND
  Garcinia buchananii bark extract is an anti-motility diarrhea remedy. We investigated whether G. buchananii bark extract has components that reduce gastrointestinal peristaltic activity via 5-HT(3) and 5-HT(4) receptors.
  
  
  METHODS
  Aqueous G. buchananii extract was separated into fractions using preparative thin layer chromatography (PTLC), and major chemical components were identified using standard tests. The anti-motility effects of the extract and its fractions (PTLC1-5) were studied through pellet propulsion assays using isolated guinea-pig distal colons.
  
  
  RESULTS
  Anti-motility (PTLC1 & PTLC5) and pro-motility (PTLC2) fractions were isolated from the extract. Flavonoids, steroids, alkaloids, tannins, and phenols were identified in the extract and PTLC1&5. The potency of the extract applied via the mucosal surface was reduced by 5-HT, 5-HT(3) receptor agonist RS-56812, 5-HT(4) receptor agonists cisapride and CJ-033466, 5-HT(3) receptor antagonist granisetron, and 5-HT(4) receptor antagonist GR-113808. The anti-motility effects of the aqueous extract and PTLC1&5 when applied serosally were reversed by RS-56812, cisapride, and CJ-033466. The 5-HT(3) receptor antagonists, granisetron and ondansetron, reduced the effects of the extract to an extent and completely reversed the anti-motility effects of PTLC1&5. GR-113808 inhibited the actions of the extract during the initial 10 min, but enhanced the extracts' anti-motility effects after 15 min. GR-113808 augmented the anti-motility activities of PTLC1 and PTLC5 by 30%.
  
  
  CONCLUSIONS
  These results indicate that the anti-motility effects of G. buchananii aqueous extract are potentially mediated by compounds that affect 5-HT(3) and 5-HT(4) receptors. Identification and characterization of the bioactive compounds within G. buchananii could lead to the discovery of new non-opiate anti-diarrhea formulations.
authors.affiliation: Department of Biological Sciences, University of Idaho, Moscow, ID 83844-3051, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Boakye
authors.forename: C
authors.initials: C
authors.lastname: Stenkamp-Strahm
authors.forename: Y
authors.initials: Y
authors.lastname: Bhattarai
authors.forename: M D
authors.initials: MD
authors.lastname: Heckman
authors.forename: S M
authors.initials: SM
authors.lastname: Brierley
authors.forename: S P
authors.initials: SP
authors.lastname: Pasilis
authors.forename: O B
authors.initials: OB
authors.lastname: Balemba
mesh_terms: D000818:Animals; D002648:Child; D003106:Colon / Q000187:drug effects / Q000502:physiology; D029760:Garcinia / Q000033:anatomy & histology / Q000737:chemistry*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006168:Guinea Pigs; D006801:Humans; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D044406:Receptors, Serotonin, 5-HT3 / Q000378:metabolism*; D044422:Receptors, Serotonin, 5-HT4 / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
chemical_list: D010936:Plant Extracts; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D044422:Receptors, Serotonin, 5-HT4