Daphnane Diterpenes from Daphne genkwa Activate Nurr1 and Have a Neuroprotective Effect in an Animal Model of Parkinson's Disease

J Nat Prod. 2016 Jun 24;79(6):1604-9. doi: 10.1021/acs.jnatprod.6b00110. Epub 2016 May 26.

Abstract

Nurr1 is an orphan nuclear receptor that is essential for the differentiation and maintenance of dopaminergic neurons in the brain, and it is a therapeutic target for Parkinson's disease (PD). During the screening for Nurr1 activators from natural sources using cell-based assay systems, a methanol extract of the combined stems and roots of Daphne genkwa was found to activate the transcriptional function of Nurr1 at a concentration of 3 μg/mL. The active components were isolated and identified as genkwanine N (1) and yuanhuacin (2). Both compounds 1 and 2 significantly enhanced the function of Nurr1 at 0.3 μM. Nurr1-specific siRNA abolished the activity of 1 and 2, strongly suggesting that transcriptional activation by 1 and 2 occurred through the modulation of Nurr1 function. Additionally, treatment with 1 and 2 inhibited 6-hydroxydopamine (6-OHDA)-induced neuronal cell death and lipopolysaccharide (LPS)-induced neuroinflammation. Moreover, in a 6-OHDA-lesioned rat model of PD, intraperitoneal administration of 2 (0.5 mg/kg/day) for 2 weeks significantly improved behavioral deficits and reduced tyrosine hydroxylase (TH)-positive dopaminergic neuron death induced by 6-OHDA injection and had a beneficial effect on the inflammatory response in the brain. Accordingly, compounds 1 and 2, the first reported Nurr1 activators of natural origin, are potential lead compounds for the treatment of PD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Daphne / chemistry*
  • Disease Models, Animal
  • Diterpenes / chemistry
  • Diterpenes / isolation & purification*
  • Diterpenes / pharmacology*
  • Dopamine / metabolism
  • Dopaminergic Neurons
  • Molecular Structure
  • Neuroprotective Agents / chemistry
  • Neuroprotective Agents / isolation & purification*
  • Neuroprotective Agents / pharmacology*
  • Nuclear Receptor Subfamily 4, Group A, Member 2 / metabolism
  • Oxidopamine / pharmacology
  • Parkinson Disease / drug therapy*
  • Plant Roots / chemistry
  • Rats
  • Rats, Sprague-Dawley
  • Republic of Korea
  • Tyrosine 3-Monooxygenase / metabolism

Substances

  • Diterpenes
  • Neuroprotective Agents
  • Nuclear Receptor Subfamily 4, Group A, Member 2
  • mezerein
  • Yuanhuacin
  • Oxidopamine
  • Tyrosine 3-Monooxygenase
  • Dopamine