Protective effect of soluble fiber from Undaria pinnatifida on vascular endothelium in hypercholesterolemic rabbits

Abstract

Dietary fiber could improve endothelial function and abnormal production of nitric oxide (NO) and elevated endothelin-1 (ET-1) concentration induce endothelial dysfunction. In the present study, we tested the effect of soluble fiber extracted from Undaria pinnatifida (UP) on endothelial function and NO and ET-1 production in hypercholesterolemic rabbits. After treatment with UP soluble fiber (5 or 10%) for 8 wk, endothelium-dependent vasorelaxation in isolated aortic rings, the concentrations of NO and ET-1 and malondialdehyde (MDA), and the expression of endothelial NO synthase (eNOS) gene were measured. The UP soluble fiber (5 or 10%) treatment significantly attenuated the impairment of endothelium-dependent vasorelaxation concomitantly with increase of plasma NO concentration and expression of aortic endothelial nitric oxide synthase (eNOS), reduction of plasma MDA level and ET-1 concentration and aortic ET-1 concentration. The present study indicates that the protective effects of UP soluble fiber on endothelium-mediated vasorelaxation may be related to an improved NO production and a reduced ET-1 concentration in hypercholesterolemic rabbits.Key words: Undaria pinnatifida, soluble fiber, endothelium, nitric oxide, endothelin-1, rabbit