Vasorelaxant Effect of Extract on Rat Mesenteric Resistance Arteries.

Background: () has been used as a traditional herbal medicine in Asian countries. Although it is well known that has beneficial effects, no sufficient research data are available on the cardiovascular effect of . We investigated whether extract has vascular effects in rat resistance arteries in this study.

Methods: To examine whether extract affects vascular reactivity, we measured isometric tension of rat mesenteric resistance arteries using a multi-wire myograph system. extract was administered after arteries were pre-contracted with high K (70 mM) or phenylephrine (5 µM). Vanillin, a single active component of , was used to treat mesenteric arteries.

Results: extract caused vascular relaxation in a concentration-dependent manner, which was endothelium-independent. To further identify the mechanism, we incubated the arteries in Ca-free solution containing high K, followed by a cumulative administration of CaCl (0.01-2.0 mM) with or without extract (250 µg/mL). The treatment of extract decreased contractile responses induced by the addition of Ca, which suggested that the extracellular Ca influx was inhibited by the extract. Moreover, an active compound of extract, vanillin, also induced vasodilation in mesenteric resistance arteries.

Conclusion: extract and its active compound, vanillin, concentration-dependently induced vascular relaxation in mesenteric resistance arteries. These results suggest that the administration of extract could help decrease blood pressure.