Oleanolic acid, a pentacyclic triterpenoid, induces rabbit platelet aggregation through a phospholipase C-calcium dependent signaling pathway

Arch Pharm Res. 2007 Feb;30(2):210-4. doi: 10.1007/BF02977696.


Oleanolic acid (3beta-hydroxy-olea-12-en-28-oic), a pentacyclic triterpenoid, exists widely in the plant kingdom and has a wide variety of pharmacological effects such as antitumor, antifungal, insecticidal, hepatoprotective and anti-HIV activities. This paper reports that oleanolic acid induces the aggregation of rabbit platelets, a mechanism was also investigated. Oleanolic acid at concentrations of 25, 50, 100 and 200 microM induced the aggregation of washed rabbit platelets in a concentration-dependent manner. Pretreating the platelets with U73122, a phospholipase C (PLC) inhibitor, blocked the oleanolic acid induced-aggregation, whereas acetylsalicylic acid (ASA), a cyclooxygenase (COX) inhibitor, had no effect. In addition, the effect of oleanolic acid on serotonin secretion, which is a marker for dense granule secretion, was determined. Oleanolic acid induced serotonin secretion in a similar concentration-dependent manner as observed with platelet aggregation. Pretreating the platelets with U73122 blocked the oleanolic acid-induced serotonin secretion and cytosolic calcium mobilization. Overall, these results suggest that oleanolic acid can induce platelet aggregation, which may be mediated by the stimulation of PLC-mediated cytosolic calcium mobilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Platelets* / drug effects
  • Blood Platelets* / enzymology
  • Blood Platelets* / metabolism
  • Calcium Signaling / drug effects*
  • Cytosol / drug effects
  • Cytosol / metabolism
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • In Vitro Techniques
  • Male
  • Molecular Structure
  • Oleanolic Acid / chemistry
  • Oleanolic Acid / pharmacology*
  • Platelet Aggregation / drug effects*
  • Rabbits
  • Serotonin / metabolism
  • Type C Phospholipases / antagonists & inhibitors
  • Type C Phospholipases / physiology*


  • Enzyme Inhibitors
  • Serotonin
  • Oleanolic Acid
  • Type C Phospholipases