Vasorelaxant and antihypertensive effects of methanolic extract from roots of Laelia anceps are mediated by calcium-channel antagonism

RMELanc-induced relaxation in aortic rings precontracted with NE, 5-HT and KCl. It also reduced NE-induced transient contraction in Ca2+-free solution and inhibited contraction induced by increasing external calcium. Nevertheless, the vasorelaxant effect of RMELanc was not reduced by ODQ, 1-alprenolol, TEA, glibenclamide, and 2-AP. Oral administration of 100 mg/kg of RMELanc exhibited a significant decrease in systolic and diastolic blood pressures in SHR rats. HPLC analysis allowed us to detect the presence of 2,7-dihydroxy-3,4,9-trimethoxyphenantrene (1), which induced a significant relaxation effect. Therefore, our results suggest that RMELanc induces vasorelaxant and antihypertensive effects by blockade of Ca2+ channels.

Graphical abstractRMELanc induces vasorelaxant and antihypertensive effects by blockade of Ca2+ channels. Moreover, (1) was detected in RMELanc by HPLC. This metabolite could be one of the active constituents.Figure optionsDownload full-size imageDownload as PowerPoint slide