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DOI: 10.1055/s-2007-993757
© Georg Thieme Verlag KG Stuttgart · New York
Gomisin A from Schisandra chinensis Induces Endothelium-Dependent and Direct Relaxation in Rat Thoracic Aorta
Publication History
Received: May 25, 2007
Revised: October 24, 2007
Accepted: October 30, 2007
Publication Date:
07 December 2007 (online)


Abstract
Schisandra chinensis (SC), a member of the Magnoliaceae family, has been used to improve the vascular health for postmenopausal women in Korea. In order to provide some scientific rationales for such effectiveness, this study investigated the vascular effects of gomisin A (GA) from SC. In the endothelium (ED)-intact rings of rat thoracic aorta, GA (1 × 10-6 to 3 × 10-4 M) caused a concentration-dependent relaxation which was markedly attenuated not only by removal of ED but also by pretreatment with N G-nitro-L-arginine (10-4 M) or 1H-[1] [2] [4]oxadiazolo[4,3-a]quinoxalin-1-one (3 × 10-5 M). Direct measurement of nitrite, a metabolite of nitric oxide (NO), confirmed that NO production in isolated aorta was increased by GA. In the ED-denuded specimens, the relaxation by GA was not abolished but reduced significantly. The relaxation by GA in ED-denuded aortic rings were clearly inhibited by calyculin A (3 × 10-8 M), an inhibitor of MLC phosphatase. Furthermore, the phenylephrine-enhanced phosphorylation ratio of MLC was significantly attenuated by GA. Based on these results, it is suggested that GA induced vascular relaxation by partially activating ED-dependent NO pathway, and partially dephosphorylation of MLC.
Key words
Schisandra chinensis - Magnoliaceae - gomisin A - vasodilation - nitric oxide