Vasorelaxing effect of 6β-hydroxybetulinic acid

Abstract

Abstract Cardiovascular diseases are currently the main causes of morbidity and mortality in the world. The available medications have undesirable side effects or lose effectiveness due to pharmacological tolerance. For this reason, it is necessary to look for new molecules and therapeutic alternatives for its treatment. 6-Hydroxybetulinic acid is a triterpene isolated from the leaves of Licania cruegeriana that demonstrated a hypotensive effect in hypertensive rats. In the present work, we evaluated the vasorelaxing effect of this triterpene in rat aortic rings (ex vivo) and its possible action mechanism. 6β-hydroxybetulinic acid develops its vasorelaxing effect in a concentration-dependent manner, and not dependent on the vascular endothelium (n:6, IC50: 9.98 µM) and induced by phenylephrine or KCl in rat aortic rings in a non-competitive manner. The 6HB-induced vasorelaxation was related to the inhibition of Ca2+ inflow from the extracellular medium and the inhibition of NO/GMPc pathway. Since vascular tone is a determinant of arterial pressure in mammals, these results could partially explain the hypotensive effect demonstrated in in vivo experiments.