Nervilia purpurea (HAYATA) SCHLETHER (Np) is an orchidaceous plant found in the middle elevations of moist mountainous regions in Taiwan. It is traditionally used for treatment of inflammation and hypertension. In this study, the antihypertensive mechanisms of this plant were examined. The crude extract of Np decreased blood pressure and relaxed the isolated thoracic aorta in rabbits, but this effect did not involve cholinergic, histaminergic, adrenergic or serotoninrgic nervous systems. LH21, LH22, and LH23 were isolated form the aqueous fraction of the crude extract of leaves of Np. LH22 relaxed norepinephrine-induced vasoconstriction, but this effect was inhibited in the absence of endothelial cells, by pretreated of rabbit aorta with methylene blue, L-NNA, or aminophylline. LH23 induced vasodilation in a dose dependent manner which was inhibited by pretreated with aminophylline, 8-phenyltheophylline, or most potently by DMPX. Chromatography analysis identified guanosine and adenosine in LH22 and LH23, respectively. In summary, we suggest that nucleotides in Np induce endothelium-dependent and - independent vasodilation which could involve the activation of the EDRF system and A2 adenosine receptors on isolated rabbit aorta.
|Number of pages||10|
|Journal||Chinese Pharmaceutical Journal|
|Publication status||Published - 1998 Dec|
All Science Journal Classification (ASJC) codes
- Pharmaceutical Science