Angelica acutiloba Exerts Antihypertensive Effect and Improves Insulin Resistance in Spontaneously Hypertensive Rats Fed with a High-Fat Diet

Abstract

Introduction: Angelica acutiloba is one of the crude drugs used in Chinese herbal medicine, and its intake is expected to improve metabolic syndrome-associated disorders. Here, we examined the effects of A. acutiloba extract (AAE) on hypertension and insulin resistance induced by the treatment of high-fat diet (HFD) to spontaneously hypertensive rats (SHRs). Then, we investigated the mechanisms associated with the effects of AAE. Methods: AAE was administered to HFD-fed SHRs. Systolic blood pressure (SBP), sympathetic nerve activity, hypothalamic angiotensin-converting enzyme (ACE) activity, blood glucose level, plasma insulin concentration, visceral fat mass, and gene expression of tumor necrosis factor-alpha (TNF-α) in the visceral fat were evaluated. Results: AAE reduced the increases in SBP and hypothalamic ACE activity observed in the HFD-fed SHRs, whereas the suppressive effect on sympathetic nerve activity was slight. Environmental stress-induced pressure and sympathetic overactivity were suppressed by the treatment of AAE. It also decreased the increase in the blood glucose level, plasma insulin concentration, homeostasis model assessment for the insulin resistance, and TNF-α gene expression in the visceral fat, but not the increase in the visceral fat mass. Conclusion: AAE has an antihypertensive effect, suppresses stress-induced hypertension, and improves insulin resistance in HFD-fed SHRs. The suppression of brain ACE activity, sympathetic nerve activity, and inflammation are partly involved in the effects of AAE.