Antihypertensive Effect of a Self-Microemulsifying System Obtained from an Ethanolic Extract of Heliopsis longipes Root in Spontaneously and L-NAME-Induced Hypertensive Rats

Arterial hypertension is a major contributor to cardiovascular disease, the leading cause of death globally. Previously, our research group has demonstrated that both organic extracts from <i>Heliopsis longipes</i> roots and affinin-its principal bioactive compound-induce vasodilation and exert antihypertensive effects in L-NAME-induced hypertensive rats. However, the poor water solubility of these extracts limits their oral administration and dosing. To address this limitation, a self-microemulsifying drug delivery system (HL-SMDS) was developed from an ethanolic extract of <i>H. longipes</i> root to enhance its aqueous solubility and oral bioavailability. This study evaluated the antihypertensive efficacy of HL-SMDS in spontaneously hypertensive and L-NAME-induced hypertensive rat models, as well as its effects on endothelial reactivity. HL-SMDS significantly reduced systolic blood pressure in both models, demonstrating greater efficacy than the crude extract, likely due to improved solubility and systemic bioavailability of the active constituents. Moreover, HL-SMDS enhanced endothelial function in aortas from L-NAME-treated rats. These findings support the potential of HL-SMDS as a lipid-based phytopharmaceutical formulation that improves the oral bioavailability and antihypertensive effect of the ethanolic extract of <i>H. longipes</i> root. HL-SMDS offers a promising strategy for the development of phytopharmaceutical drugs to treat hypertension.