Hypertension requires proper management because of the increased risk of cardiovascular disease and death. For this purpose, functional foods containing tannins have been considered an effective treatment. Sanguisorbae radix (SR) also contains various tannins; however, there have been no studies on its vasorelaxant or antihypertensive effects. In this study, the vasorelaxant effect of the ethanol extract of SR (SRE) was investigated in the thoracic aorta of Sprague Dawley rats. SRE (1, 3, 10, 30, and 100 μg/mL) showed this effect in a dose-dependent manner, and its mechanisms were related to the NO/cGMP pathway and voltage-gated K⁺ channels. Concentrations of 300 and 1000 μg/mL blocked the influx of extracellular Ca²⁺ and inhibited vasoconstriction. Moreover, 100 μg/mL of SRE showed a relaxing effect on blood vessels constricted by angiotensin II. The hypotensive effect of SRE was investigated in spontaneously hypertensive rats (SHR) using the tail-cuff method. Blood pressure significantly decreased 4 and 8 h after 1000 mg/kg of SRE administration. Considering these hypotensive effects and the vasorelaxant mechanisms of SRE, our findings suggests that SRE can be used as a functional food to prevent and treat hypertension. Further studies are needed for identifying the active components and determining the optimal dosage.

Cnidium monnieri (L.) Cusson, a member of the Apiaceae family, is rich in coumarins, such as imperatorin and osthole. Cnidium monnieri fruit (CM) has a broad range of therapeutic potential that can be used in anti-bacterial, anti-cancer, and sexual dysfunction treatments. However, its efficacy in lowering blood pressure through vasodilation remains unknown. This study aimed to assess the potential therapeutic effect of CM 50% ethanol extract (CME) on hypertension and the mechanism of its vasorelaxant effect. CME (1–30 µg/mL) showed a concentration-dependent vasorelaxation on constricted aortic rings in Sprague Dawley rats induced by phenylephrine via an endothelium-independent mechanism. The vasorelaxant effect of CME was inhibited by blockers of voltage-dependent and Ca²⁺-activated K⁺ channels. Additionally, CME inhibited the vascular contraction induced by angiotensin II and CaCl₂. The main active compounds of CM, i.e., imperatorin (3–300 µM) and osthole (1–100 µM), showed a concentration-dependent vasorelaxation effect, with half-maximal effective concentration values of 9.14 ± 0.06 and 5.98 ± 0.06 µM, respectively. Orally administered CME significantly reduced the blood pressure of spontaneously hypertensive rats. Our research shows that CME is a promising treatment option for hypertension. However, further studies are required to fully elucidate its therapeutic potential.

Natural compounds, known for diverse pharmacological properties, have attracted attention as potential sources for hypertension treatment. Previous studies have revealed the hypotensive effect and vascular relaxation of prunetin, a natural compound derived from Prunus yedoensis. However, the potential blood pressure-lowering and vasorelaxant effects of sakuranetin, another representative compound found in plants belonging to the genus Prunus, have remained unexplored. We aimed to fill this gap by investigating the hypotensive and vasorelaxant effects of sakuranetin in rats. Results indicated that sakuranetin, particularly in the sakuranetin 20 mg/kg group, led to significant reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) by −14.53 ± 5.64% and −19.83 ± 6.56% at 4 h after administration. In the sakuranetin 50 mg/kg group, the SBP and DBP decreased by −13.27 ± 6.86% and −16.62 ± 10.01% at 2 h and by −21.61 ± 4.49% and −30.45 ± 5.21% at 4 h after administration. In addition, we identified the vasorelaxant effects of sakuranetin, attributing its mechanisms to the inhibition of calcium influx and the modulation of angiotensin II. Considering its hypotensive and vasorelaxant effects, sakuranetin could potentially serve as an antihypertensive agent. However, further research is required to evaluate the safety and long-term efficacy.

Hypertension is the crucial modifiable risk factor for cardiovascular diseases, and efforts to identify functional foods that are effective for hypertension control are increasing. The nutgall tree (NT, Rhus chinensis Mill.) is used in traditional medicine and food because of its medicinal value. However, the role of NT in hypertension has not been investigated. Therefore, the hypotensive effect of NT leaf ethanol extract (NTE) was investigated in spontaneously hypertensive rats (SHRs). SHRs were allocated to three groups (control, 300, or 1000 mg/kg NTE), and blood pressure was measured before and after oral administration. Systolic and diastolic blood pressure significantly decreased in the NTE 1000 mg/kg group and was the lowest at 2 h after administration (−26.4 ± 10.3, −33.5 ± 9.8%, respectively). Daily NTE administration for five days also resulted in a similar effect. Further, the vasorelaxant effects and related mechanisms were investigated in the aortas of Sprague Dawley rats. NTE showed the dose-dependent blood-vessel-relaxing effect, and its mechanism involves the NO-sGC-cGMP pathway, activation of K⁺ channels, and reduction in the vasoconstrictive action of angiotensin II. Therefore, our study provides basic data indicating the potential use of NTE as a functional food for high blood pressure.

Hypertension is one of the most common chronic diseases, and its prevalence is increasing worldwide. Lindera glauca (Siebold & Zucc.) Blume, known as grayblue spicebush (GS), has been used as food and for medicinal purposes; however, studies about its hypotensive or vasorelaxant effects are lacking. Therefore, the hypotensive effect of an ethanolic extract of the GS branch (GSE) was investigated in 15-week-old spontaneously hypertensive rats (SHRs) using the tail cuff method. The GSE administration group (1000 mg/kg SHR body weight) showed a decrease in their systolic and diastolic blood pressure measured 4 h after its administration. In addition, we investigated its vasorelaxant effect using the thoracic aorta dissected from Sprague-Dawley rats. The GSE (0.5, 1, 2, 5, 10, and 20 μg/mL) showed an endothelium-dependent vasorelaxant effect, and its mechanisms were found to be relevant to the inward rectifier, voltage-dependent, and non-selective K⁺ channels. Moreover, the GSE (20 μg/mL) showed an inhibitory effect on aortic rings constricted with angiotensin II. Considering its hypotensive and vasorelaxant effects, GSE has potential as a functional food to help treat and prevent high blood pressure. However, further studies on the identification of the active components of GSE and safety evaluations of its use are needed.

Previous studies have revealed the medicinal and therapeutic effects of Galla chinensis. However, no studies have focused on the antihypertensive effects of G. chinensis. Therefore, we aimed to determine the vasorelaxant and hypotensive effects of G. chinensis 50% ethanolic extract (GCE). To evaluate the vascular relaxing effect of GCE, experiments were conducted using aortic segments dissected from Sprague Dawley rats. GCE showed a vasorelaxant effect via the nitric oxide/cyclic guanosine 3′,5′-monophosphate pathway, inhibiting Ca²⁺ channels, and activating K⁺ channels. The hypotensive effects of GCE were evaluated in spontaneously hypertensive rats (SHRs). The SHRs were randomly divided into a control group and orally administered GCE group (100 or 300 mg/kg). The systolic and diastolic blood pressure decreased significantly by −19.47 ± 4.58% and −31.14 ± 7.66% in the GCE 100 mg/kg group, and −21.64 ± 2.40% and −31.91 ± 5.75% in the GCE 300 mg/kg group at 4 h after administration. Considering its vasorelaxant and hypotensive effects, our results indicate that GCE may be a valuable solution for the control of hypertension. However, further studies on the long-term administration and toxicity of GCE are required.