Peach (Prunus persica (L.) Batsch) is a popular fruit consumed by people worldwide, owing to its pleasant flavor and high mineral nutrient content. A few plants from the genus Prunus, such as Prunus yedoensis, Prunus cerasus, and Prunus serotina have shown vasorelaxant and vasodilatory effects, to date, no study has investigated the vasorelaxation effects of the P. persica branch extract (PPE). The vasorelaxant effect of PPE was endothelium-dependent, and it was related to the NO-sGC-cGMP, vascular prostacyclin, and muscarinic receptor transduction pathway. K⁺ channels, such as the BK_Ca, K_V, and K_ATP channels, were partially associated with PPE-induced vasorelaxation. PPE was effective in relaxing serotonin (5-HT)- or angiotensin II-induced contraction; furthermore, PPE attenuated Ca²⁺-induced vasoconstriction by IP₃ receptors in the SR membrane, but its vasorelaxant effect was not associated with the influx of extracellular Ca²⁺ via receptor-operative Ca²⁺ channels or voltage-dependent Ca²⁺ channels. Recognizing the rising use of functional foods for hypertension treatment, our findings imply that PPE may be a natural antihypertensive agent.

Curcumin, a curcuminoid known as the main bioactive compound of turmeric, is used in foods, cosmetics, and pharmaceutical products. Amlodipine is a general antihypertensive drug used in combination with various other antihypertensive agents. To date, no studies have examined the effects of the co-administration of amlodipine with curcumin. In this study, the vasodilatory effects of curcumin, amlodipine, and the co-administration of curcumin with amlodipine on isolated rat aortic rings pre-contracted with phenylephrine were evaluated, and the hypotensive effects were evaluated using the tail cuff method. To measure blood pressure, male spontaneously hypertensive rats were divided into four groups, each containing six rats, as follows: amlodipine 1 mg/kg alone treated, amlodipine 1 mg/kg with curcumin 30 mg/kg treated, amlodipine 1 mg/kg with curcumin 100 mg/kg treated, and amlodipine 1 mg/kg with curcumin 300 mg/kg treated groups. Amlodipine and curcumin were intraperitoneally injected, and systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured at 1, 2, 4, and 8 h after administration. The combined administration of curcumin and amlodipine induced a stronger vasorelaxant effect than amlodipine alone. However, co-administration did not significantly lower SBP and DBP compared to the single administration of amlodipine. The results of this study suggest that hypertensive patients taking amlodipine can consume curcumin or turmeric for food or other medical purposes without inhibiting the blood pressure-lowering effect of amlodipine.

Hypertension is one of the most important risk factors for cardiovascular disease (CVD) and a worldwide problem. Despite increases in the development of synthetic drugs for hypertension treatment, the rate of untreated and uncontrolled hypertension remains high. These drugs are effective, but can also cause side effects. Approximately 80% of the world population uses herbal medicines because of their low toxicity and better acceptability by the human body. Therefore, we attempted to identify natural medications for treating hypertension. The 70% ethanol extract of Angelica decursiva root (ADE) shows strong vasorelaxant potential, but no studies have investigated the mechanisms underlying the vasorelaxation effect of A. decursiva. Dried root of A. decursiva was identified by DNA sequencing and was extracted once with 1 L 70% ethanol (EtOH) for 3 h in a reflux apparatus at 70 °C. ADE was evaluated for its vasorelaxant effects in rat thoracic aortas. Various inhibitors of ADE-induced vasorelaxation were used. ADE showed vasorelaxant effects on the intact and denuded endothelium of aortic rings pre-contracted with phenylephrine and KCl in Krebs-Henseleit solution. Tetraethylammonium and 4-aminopyridine did not alter ADE-induced vasorelaxation. However, the vasorelaxant effect of ADE was partially inhibited by pre-treatment with glibenclamide an ATP-sensitive K+ channel blocker. Furthermore, ADE concentration-dependently inhibited Ca2+ supplementation-induced vasoconstriction of aortic rings that had been pretreated with phenylephrine or KCl in Ca2+-free Krebs-Henseleit solution. These results suggest that ADE-induced vasorelaxation occurred in an endothelium-independent manner. The vasorelaxant effects of ADE were correlated with blockade of the KATP channel and inhibition of Ca2+ influx via receptor-operative Ca2+ channels or voltage-dependent Ca2+ channels.

Korean plum (Prunus mume (Siebold) Siebold & Zucc.) has long been used as a health food or herbal medicine in Asia. Previous studies have shown that several plants of the genus Prunus have vasodilatory and antihypertensive effects; we hypothesized that P. mume branches may have a vasorelaxant effect. In this study, we evaluated the effects and action mechanism of 70% ethanol extract of P. mume branch (PMB) on isolated rat aortic rings. Inhibitors such as NG-nitro-l-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, methylene blue, indomethacin, atropine, tetraethylammonium chloride, glibenclamide, 4-aminopyridine and BaCl₂ were used to investigate the mechanism of vasodilation responsible for the vascular relaxation. PMB (2–30 μg/mL) induced vasorelaxation in the presence of vascular endothelium, and all inhibitors used in this study affected the degree of relaxation. These results suggest that the vasorelaxant effect of PMB is endothelium-dependent and affects the nitric oxide-cyclic guanosine monophosphate pathway, prostacyclin pathway, muscarinic receptor pathway, and potassium channels. Our study explains that PMB may be another approach to hypertension treatment to reduce the burden of cardiovascular disease.