Xanthones from the roots of Polygala caudata and their antioxidation and vasodilatation activities in vitro.
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.
Lin
Li-Lin
LL
Institute of Medicinal Plant Development, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, PR China.
Huang
Feng
F
Chen
Si-Bao
SB
Yang
Da-Jian
DJ
Chen
Shi-Lin
SL
Yang
Jun-Shan
JS
Xiao
Pei-Gen
PG
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001011:Aorta / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018517:Plant Roots; D031801:Polygala; D051381:Rats; D017208:Rats, Wistar; D016897:Respiratory Burst / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D044004:Xanthones / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use
D000975:Antioxidants; D010936:Plant Extracts; D014665:Vasodilator Agents; D044004:Xanthones