Impairment of Vascular Function of Rat Thoracic Aorta in an Endothelium-Dependent Manner by Shikonin/Alkannin and Derivatives Isolated from Roots of Macrotomia euchroma

Chien-Ming Hu, Yu Wen Cheng, Hui Wen Cheng, Jaw Jou Kang

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The effects of a naphthoquinone analogue, shikonin/alkannin (SA) and derivatives (acetylshikonin and β,β-dimethylacrylshikonin), on vascular reactivity were studied with isolated rat aortic rings. At lower concentrations, SA and its derivatives concentration-dependently inhibit the agonist-induced (acetylcholine and histamine) relaxation in PE precontracted aorta in an endothelium-dependent manner with IC 50 values ranging from 0.2 to 1.5 μM. In addition to the effect on agonist-induced vasorelaxation, the Ca 2+ ionophore A23187-induced vasorelaxation was also inhibited or reversed by SA. However, SA had no effect on sodium nitroprusside-induced (guanylate cyclase activator) vasorelaxation. These data suggested that SA and its derivatives might be acting as inhibitors of nitric oxide synthesis in endothelium. At a concentration greater than 10 μM, SA induced contraction of intact but not denuded aorta which could be inhibited by prior treatment with indomethacin, a cyclooxygenase inhibitor. In summary, the results from this study showed that SA and its derivatives inhibited agonist-induced relaxation at lower concentrations and induced vasocontraction at higher concentrations. All the effects seen with SA were endothelium- dependent, however, through different mechanisms.

Original languageEnglish
Pages (from-to)23-28
Number of pages6
JournalPlanta Medica
Volume70
Issue number1
DOIs
Publication statusPublished - Jan 2004

Fingerprint

chest
aorta
endothelium
Thoracic Aorta
blood vessels
Endothelium
Blood Vessels
Rats
chemical derivatives
Derivatives
rats
vasodilation
Vasodilation
agonists
Aorta
Histamine Agonists
Naphthoquinones
naphthoquinones
Cholinergic Agonists
guanylate cyclase

Keywords

  • Boraginaceae
  • Macrotomia euchroma
  • Naphthoquinone
  • Nitric oxide synthase
  • Shikonin/alkannin

ASJC Scopus subject areas

  • Plant Science
  • Drug Discovery
  • Organic Chemistry
  • Pharmacology

Cite this

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title = "Impairment of Vascular Function of Rat Thoracic Aorta in an Endothelium-Dependent Manner by Shikonin/Alkannin and Derivatives Isolated from Roots of Macrotomia euchroma",
abstract = "The effects of a naphthoquinone analogue, shikonin/alkannin (SA) and derivatives (acetylshikonin and β,β-dimethylacrylshikonin), on vascular reactivity were studied with isolated rat aortic rings. At lower concentrations, SA and its derivatives concentration-dependently inhibit the agonist-induced (acetylcholine and histamine) relaxation in PE precontracted aorta in an endothelium-dependent manner with IC 50 values ranging from 0.2 to 1.5 μM. In addition to the effect on agonist-induced vasorelaxation, the Ca 2+ ionophore A23187-induced vasorelaxation was also inhibited or reversed by SA. However, SA had no effect on sodium nitroprusside-induced (guanylate cyclase activator) vasorelaxation. These data suggested that SA and its derivatives might be acting as inhibitors of nitric oxide synthesis in endothelium. At a concentration greater than 10 μM, SA induced contraction of intact but not denuded aorta which could be inhibited by prior treatment with indomethacin, a cyclooxygenase inhibitor. In summary, the results from this study showed that SA and its derivatives inhibited agonist-induced relaxation at lower concentrations and induced vasocontraction at higher concentrations. All the effects seen with SA were endothelium- dependent, however, through different mechanisms.",
keywords = "Boraginaceae, Macrotomia euchroma, Naphthoquinone, Nitric oxide synthase, Shikonin/alkannin",
author = "Chien-Ming Hu and Cheng, {Yu Wen} and Cheng, {Hui Wen} and Kang, {Jaw Jou}",
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AU - Cheng, Yu Wen

AU - Cheng, Hui Wen

AU - Kang, Jaw Jou

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N2 - The effects of a naphthoquinone analogue, shikonin/alkannin (SA) and derivatives (acetylshikonin and β,β-dimethylacrylshikonin), on vascular reactivity were studied with isolated rat aortic rings. At lower concentrations, SA and its derivatives concentration-dependently inhibit the agonist-induced (acetylcholine and histamine) relaxation in PE precontracted aorta in an endothelium-dependent manner with IC 50 values ranging from 0.2 to 1.5 μM. In addition to the effect on agonist-induced vasorelaxation, the Ca 2+ ionophore A23187-induced vasorelaxation was also inhibited or reversed by SA. However, SA had no effect on sodium nitroprusside-induced (guanylate cyclase activator) vasorelaxation. These data suggested that SA and its derivatives might be acting as inhibitors of nitric oxide synthesis in endothelium. At a concentration greater than 10 μM, SA induced contraction of intact but not denuded aorta which could be inhibited by prior treatment with indomethacin, a cyclooxygenase inhibitor. In summary, the results from this study showed that SA and its derivatives inhibited agonist-induced relaxation at lower concentrations and induced vasocontraction at higher concentrations. All the effects seen with SA were endothelium- dependent, however, through different mechanisms.

AB - The effects of a naphthoquinone analogue, shikonin/alkannin (SA) and derivatives (acetylshikonin and β,β-dimethylacrylshikonin), on vascular reactivity were studied with isolated rat aortic rings. At lower concentrations, SA and its derivatives concentration-dependently inhibit the agonist-induced (acetylcholine and histamine) relaxation in PE precontracted aorta in an endothelium-dependent manner with IC 50 values ranging from 0.2 to 1.5 μM. In addition to the effect on agonist-induced vasorelaxation, the Ca 2+ ionophore A23187-induced vasorelaxation was also inhibited or reversed by SA. However, SA had no effect on sodium nitroprusside-induced (guanylate cyclase activator) vasorelaxation. These data suggested that SA and its derivatives might be acting as inhibitors of nitric oxide synthesis in endothelium. At a concentration greater than 10 μM, SA induced contraction of intact but not denuded aorta which could be inhibited by prior treatment with indomethacin, a cyclooxygenase inhibitor. In summary, the results from this study showed that SA and its derivatives inhibited agonist-induced relaxation at lower concentrations and induced vasocontraction at higher concentrations. All the effects seen with SA were endothelium- dependent, however, through different mechanisms.

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