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 Heliopsis longipes 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 H. longipes 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 H. longipes root. HL-SMDS offers a promising strategy for the development of phytopharmaceutical drugs to treat hypertension.