Vasorelaxing effects of Caesalpinia sappan involvement of endogenous nitric oxide.
Methanolic extract and two purified compounds (brazilin and hematoxylin) from Caesalpinia sappan were examined for their relaxant effects in isolated rat thoracic aorta. The methanolic extract significantly and dose-dependently relaxed the alpha1-receptor agonist phenylephrine-precontracted aortic rings, without affecting passive tension of these vessels. Removal of the vascular endothelium, inhibition of nitric oxide (NO) synthase with 0.1 mM Nomega-nitro-L-arginine and of cGMP biosynthesis with 10 microM methylene blue abolished the vasorelaxant effects of the herbal extract at doses up to 30 microg/ml. Similar vasorelaxant effects were observed with brazilin and hematoxylin. Therefore, these results suggest that brazilin and hematoxylin may be responsible for the vascular relaxant effects of C. sappan, via endogenous NO and subsequent cGMP formation. The vascular relaxant effects of the plant may contribute to its therapeutic actions.
Xie
Y W
YW
lnstitute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, People's Republic of China.
Ming
D S
DS
Xu
H X
HX
Dong
H
H
But
P P
PP
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000201:enzymology*; D001578:Benzopyrans / Q000494:pharmacology; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology; D007887:Fabaceae / Q000737:chemistry / Q000627:therapeutic use; D006416:Hematoxylin / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D008517:Phytotherapy; D010946:Plants, Medicinal; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
D001578:Benzopyrans; D004365:Drugs, Chinese Herbal; D014665:Vasodilator Agents; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; C044362:brazilin; D006416:Hematoxylin