Xanthones from the roots of Polygala caudata and their antioxidation and vasodilatation activities in vitro

Planta Med. 2005 Apr;71(4):372-5. doi: 10.1055/s-2005-864108.

Abstract

Three new xanthones, 2-hydroxy-1,6,7-trimethoxyxanthone (1), 1,4-dimethoxy-2,3-methylenedioxyxanthone (2), and 7-hydroxy-1,2-dimethoxyxanthone (3), together with five known compounds, 2,7-dihydroxy-1-methoxyxanthone (4), 1-methoxy-2,3-methylenedioxyxanthone (5), 7-hydroxy-1-methoxyxanthone (6), euxanthone (1,7-dihydroxyxanthone) (7), and gentitein (1,3,7-trihydroxyxanthone) (8), were isolated from the roots of Polygala caudata. Their structures were established on the basis of spectral evidence. In the antioxidation activity screening in vitro with luminol chemiluminescence methods, compounds 1 - 5 and 7 and 8 showed H2O2 scavenger activity, with a scavenging effect of 58.4 - 94.5% at 10 microg/mL, and 26.0 - 84.7% at 2 microg/mL. Compounds 4 and 8 also exhibited scavenging effects on the reactive oxygen free radicals produced by macrophage respiratory bursts, with a scavenging effect of 71.7% and 63.4% at 10 microg/mL, 41.2% and 47.8% at 2 microg/mL, respectively. In the vasodilatation assay, compounds 4 - 7 exhibited relaxing activity on the contractions evoked by KCl in Wistar rat thoracic aorta rings in a dose-dependent manner.

MeSH terms

  • Animals
  • Antioxidants / administration & dosage
  • Antioxidants / pharmacology*
  • Antioxidants / therapeutic use
  • Aorta / drug effects
  • Dose-Response Relationship, Drug
  • Muscle, Smooth, Vascular / drug effects
  • Phytotherapy*
  • Plant Extracts / administration & dosage
  • Plant Extracts / pharmacology*
  • Plant Extracts / therapeutic use
  • Plant Roots
  • Polygala*
  • Rats
  • Rats, Wistar
  • Respiratory Burst / drug effects
  • Vasodilation / drug effects
  • Vasodilator Agents / administration & dosage
  • Vasodilator Agents / pharmacology*
  • Vasodilator Agents / therapeutic use
  • Xanthones / administration & dosage
  • Xanthones / pharmacology
  • Xanthones / therapeutic use

Substances

  • Antioxidants
  • Plant Extracts
  • Vasodilator Agents
  • Xanthones