Effects of triterpenoids from Poria cocos Wolf on the serotonin type 3A receptor-mediated ion current in Xenopus oocytes

Eur J Pharmacol. 2009 Aug 1;615(1-3):27-32. doi: 10.1016/j.ejphar.2009.04.063. Epub 2009 May 14.


Poria cocos Wolf (P. cocos Wolf) is used to treat chronic gastritis, edema, nephrosis, gastric atony, acute gastroenteric catarrh, dizziness, emesis and vomiting. Triterpenoids are a class of natural compounds produced by P. cocos Wolf that contain acyclic 30-carbon precursors. In this study, we investigated the effect of triterpenoids (PA, Pachymic acid; DA, dehydroeburicoic acid; HA, 3beta-hydroxylanosta-7,9(11),24-trien-21-oic acid) on human 5-hydroxytryptamine 3A (5-HT(3A)) receptor channel activity, which is one of the ligand-gated ion channel families. The two-electrode voltage-clamp technique was used to examine the 5-HT3A mediated current. The inhibitory effect of triterpenoids on 5HT-induced inward current (I(5-HT)) occurred in a concentration dependent and reversible manner. Furthermore, the half-inhibitory concentrations (IC(50)) of PA, DA and HA were 3.2+/-0.2, 5.5+/-0.6 and 1.4+/-0.2 microM, respectively. This corresponded to an order of potency for the inhibition of I(5-HT) in oocytes expressing human 5-HT(3A) receptor of HA>PA>DA. Finally, inhibition of I(5HT) by triterpenoids occurred in a non-competitive manner, while inhibition by HA and PA showed more voltage-dependency. Taken together, these results indicate that triterpenoids may regulate the expressed 5-HT(3A) receptors in Xenopus oocytes. Furthermore, this regulation of the ligand-gated ion channel activity by triterpenoids may be one of the pharmacological actions of P. cocos Wolf.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • In Vitro Techniques
  • Lanosterol / analogs & derivatives*
  • Lanosterol / pharmacology
  • Membrane Potentials / drug effects
  • Microinjections
  • Molecular Structure
  • Oocytes / drug effects*
  • Oocytes / physiology
  • Patch-Clamp Techniques
  • Poria / chemistry*
  • RNA, Complementary / metabolism
  • Receptors, Serotonin / genetics
  • Receptors, Serotonin / physiology*
  • Receptors, Serotonin, 5-HT3
  • Serotonin / pharmacology
  • Serotonin Antagonists / pharmacology
  • Triterpenes / chemistry
  • Triterpenes / pharmacology*
  • Tropanes / pharmacology
  • Xenopus laevis


  • 3-hydroxylanosta-7,9(11),24-trien-21-oic acid
  • HTR3A protein, human
  • RNA, Complementary
  • Receptors, Serotonin
  • Receptors, Serotonin, 5-HT3
  • Serotonin Antagonists
  • Triterpenes
  • Tropanes
  • dehydroeburiconic acid
  • Lanosterol
  • Serotonin
  • bemesetron
  • pachymic acid