Antidepressant effects of the extract YZ-50 from Polygala tenuifolia in chronic mild stress treated rats and its possible mechanisms

Pharm Biol. 2010 Jul;48(7):794-800. doi: 10.3109/13880200903280034.


YZ-50 is an active fraction obtained from the root of Polygala tenuifolia Willd. (Polygalaceae) extract and it has been reported previously to exert beneficial effects on mental health in depressed sufferers, however, its mechanism of action remains unresolved. This study utilized the chronic mild stress (CMS) model of depression in Sprague-Dawley rats to evaluate the effects of YZ-50 on depressive behaviors. Furthermore, we tested the hypothesis that the capacity of YZ-50 to reverse the harmful effects of CMS is relative to the hypothalamo-pituitary-adrenal (HPA) system and brain-derived neurotrophic factor (BDNF) in the hippocampus. Repeated administration of YZ-50 for 28 days at the doses of 140 and 280 mg/kg in CMS, YZ-50 reversed the CMS-induced changes in sucrose consumption, plasma corticosterone levels and open field activity. In addition, CMS significantly decreased hippocampal BDNF mRNA levels. However, YZ-50 counteracted a decrease in hippocampal BDNF mRNA caused by CMS. In conclusion, YZ-50 reversed the harmful effects of CMS on mood and behaviors in rats and it possesses an antidepressant property that is at least in part mediated by the neuroendocrine and neuropropective systems, and it is likely that the HPA system plays an important role in this process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenocorticotropic Hormone / blood
  • Animals
  • Antidepressive Agents / therapeutic use*
  • Brain-Derived Neurotrophic Factor / genetics
  • Brain-Derived Neurotrophic Factor / metabolism
  • Corticosterone / blood
  • Depression / drug therapy*
  • Drug Evaluation, Preclinical
  • Drugs, Chinese Herbal / isolation & purification
  • Drugs, Chinese Herbal / pharmacology
  • Drugs, Chinese Herbal / therapeutic use*
  • Hippocampus / drug effects
  • Hippocampus / metabolism
  • Male
  • Motor Activity / drug effects
  • Phytotherapy*
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use*
  • Polygalaceae*
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Stress, Psychological / drug therapy
  • Weight Gain / drug effects


  • Antidepressive Agents
  • Brain-Derived Neurotrophic Factor
  • Drugs, Chinese Herbal
  • Plant Extracts
  • YZ-50 extract
  • Adrenocorticotropic Hormone
  • Corticosterone