Vasorelaxant effect of osterici radix ethanol extract on rat aortic rings

Vasorelaxant and Blood Pressure-Lowering Effects of Cnidium monnieri Fruit Ethanol Extract in Sprague Dawley and Spontaneously Hypertensive Rats

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.

New insights on mode of action of vasorelaxant activity of simvastatin

Simvastatin is a semisynthetic inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and is used extensively to treat atherosclerotic cardiovascular disease. Apart from the lipid-lowering effect, simvastatin has been documented to offer impressive vasorelaxant activity. However, the mechanism associated with this vasorelaxant activity has yet not been substantially explored. Thus, the present study has aimed to elucidate the mechanism(s) associated with simvastatin-induced vasorelaxation using an established rat aortic ring model. The results from the study depicted that simvastatin caused significant relaxation in aortic rings pre-contracted with phenylephrine and potassium chloride (KCl). The vasorelaxant effect of simvastatin was attenuated by methylene blue (sGC-dependent cyclic guanosine monophosphate (cGMP) inhibitor), N^G-nitro-L-arginine methyl ester (L-NAME; NO synthase inhibitor), 4-aminopyridine (K_v blocker), glibenclamide (K_ATP blocker), and barium chloride (K_ir blocker). In addition, the vasorelaxant effect of simvastatin was slightly reduced by PD123319 (angiotensin II type 2 receptor (AT₂R) antagonist). However, indomethacin (COX inhibitor), 1H-[1,2,4]Ox adiazolol [4,3-α]quinoxalin-1-one (ODQ; selective soluble guanylate cyclase (sGC) inhibitor), losartan (angiotensin II type 1 receptor (AT₁R) antagonist), atropine (muscarinic receptor blocker), and tetraethyl ammonium (TEA; K_Ca blocker) did not affect the vasorelaxant effect of simvastatin. Furthermore, simvastatin was found to attenuate the release of calcium (Ca²⁺) from intracellular stores in the presence of ruthenium red (ryanodine receptor, RyR inhibitor) and extracellular stores via nifedipine (voltage-operated Ca²⁺ channels, VOCC blocker) and SK&F96365 (receptor-operated Ca²⁺ channel, ROCC blocker). Thus, it can be concluded that the vasorelaxant effect of simvastatin involves NO/cGMP pathways, AT₂R receptors, Ca²⁺ channels, and K⁺ channels.

Antihypertensive and vasorelaxant effects of Rumex vesicarius (L.) through receptor-operated calcium channels in hypertensive rats

AIMS

The aim of the study was to assess the antihypertensive activity of Rumex vesicarius.

BACKGROUND

The genus Rumex (sorrel, Polygonaceae), containing approximately 200 species, is distributed worldwide (African, European, Asian, and American countries). It is widely used in traditional medicine as analgesic, diuretic, antispasmodic, and antihypertensive plants.

OBJECTIVE

This study aimed to assess the possible antihypertensive vasorelaxant capacity and effect on angiotensin-converting enzyme 2 (ACE-2) of the aqueous extract of Rumex vesicarius (R. vesicarius).

MATERIAL AND METHODS

In the present study, the aqueous extract of R. vesicarius (AERV) was prepared, its antihypertensive activity was examined in N(ω)-nitro-L-arginine methyl ester(L-NAME)-induced hypertensive rats, and its vasorelaxant ability along with its effect on stimulating or inhibiting ACE-2 were performed in isolated rat thoracic aorta.

RESULTS

The results indicated that AERV decreased the systolic, diastolic, mean, and mean arterial blood pressure in hypertensive rats. The data revealed that AERV exerted its antihypertensive effect through vasodilatory properties via an endothelium-independent pathway. Interestingly, the study demonstrated that the vasorelaxation ability of AERV might be mediated through receptor-operated calcium channels (ROCC). However, AERV extract had no effect on either stimulating or inhibiting ACE-2.

CONCLUSION

The present study demonstrates clearly the antihypertensive and vasorelaxant activities of R. vesicarius in hypertensive rats, supporting its beneficial action as an antihypertensive agent.

Pharmacological Role of Ostericum koreanum: A Short Viewpoint

Ostericum koreanum Maxim., a perennial medicinal plant native to Asian countries, is traditionally exploited in Korean Oriental and Chinese Herbal Medicine. It has been used in the treatment of neuralgia, respiratory problems, and joint pain due to its rich content of phytochemicals. Therefore, the significant role of compounds present in O. koreanum should not be overlooked to explore and develop drugs against diseases. The purpose of this review is to provide a reference for researchers and to describe the phytochemical constituents and pharmacological activity of O. koreanum. In this mini review, we have collected the data from 1980 to 2020 regarding the phytochemicals present and pharmacological activities of this plant. Our findings indicated that this plant possesses a rich source of phytochemicals that have significant pharmacological activities, such as anti-microbial, anti-inflammatory, anti-pyretic, anti-influenza, anti-cancer, and neuroprotective. These phytochemicals have promising pharmacological activity which should be further explored for the treatment of various diseases.

Simultaneous Determination of 12 Marker Components in Yeonkyopaedok-san Using HPLC–PDA and LC–MS/MS

Yeonkyopaedok-san is a traditional Korean medicine used in the early treatment of boils. In the present study, its 12 marker components for quality control were determined using high-performance liquid chromatography (HPLC) with photodiode array detection and ultra-performance liquid chromatography–mass spectrometry with tandem mass spectrometry (UPLC–MS/MS). The investigated 12 marker components of Yeonkyopaedok-san were as follows: 3-caffeoylquinic acid, cimifugin 7-glucoside, liquiritin apioside, ferulic acid, narirutin, 5-O-methylvisammioside, naringin, neohesperidin, oxypeucedanin hydrate, arctigenin, glycyrrhizic acid, and 6-gingerol. The analytical column used for the separation of the 12 marker analytes in Yeonkyopaedok-san was a Waters SunFire C18 column (4.6 mm × 250 mm, 5 μm). The two mobile phases used were 0.1% (v/v) aqueous formic acid and 0.1% (v/v) formic acid in acetonitrile. In the UPLC–MS/MS analysis, all components were separated using a Waters ACQUITY UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm). The two mobile phases used were 0.1% (v/v) aqueous formic acid and acetonitrile. The coefficient of determination of the calibration curves in both analysis systems showed good linearity (>0.99). The amounts of the 12 marker components in Yeonkyopaedok-san determined using HPLC–photodiode array detection and UPLC–MS/MS analyses were found to be 0.14–9.00 mg/g and 2.35–853.11 μg/g, respectively.

Vasorelaxant effects of Angelica decursiva root on isolated rat aortic rings

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Vitamin K3 inhibits mouse uterine contraction in vitro via interference with the calcium transfer and the potassium channels

Previous studies have demonstrated vitamin K3 had a great relief to smooth muscle spastic disorders, but no researches have yet pinpointed its possible anti-contractile activity in the uterus. Here, we evaluated the effect of vitamin K3 on myometrial contractility and explored the possible mechanisms of vitamin K3 action. Myograph apparatus were used to record the changes in contractility of isolated mouse uterine strips in a tissue bath. Uterine strips were exposed to vitamin K3 or vehicle. Vitamin K3 suppressed spontaneous contractions in a concentration dependent manner. It significantly decreased the contractile frequency induced by PGF2ɑ but not their amplitude (expect 58.0 μM). Prior incubation with vitamin K3 reduced the effectiveness of PGF2ɑ-induced contraction. The antispasmodic effect of vitamin K3 was also sensitive to potassium channel blockers, such as tetraethylammonium, 4-aminopyridine, iberiotoxin) but not to the nitric oxide related pathway blockers. High concentrations (29.0, 58.0 μM) of vitamin K3 weakened the Ca(2+) dose response and inhibited phase 1 contraction (intracellular stored calcium release). These dates suggest that vitamin K3 specifically suppresses myometrial contractility by affecting calcium and potassium channels; thus, this approach has potential therapy for uterine contractile activity related disorders.

Relaxation of rat aorta by farrerol correlates with potency to reduce intracellular calcium of VSMCs

Farrerol, isolated from Rhododendron dauricum L., has been proven to be an important multifunctional physiologically active component, but its vasoactive mechanism is not clear. The present study was performed to observe the vasoactive effects of farrerol on rat aorta and to investigate the possible underlying mechanisms. Isolated aortic rings of rat were mounted in an organ bath system and the myogenic effects stimulated by farrerol were studied. Intracellular Ca²⁺ ([Ca²⁺]_in) was measured by molecular probe fluo-4-AM and the activities of L-type voltage-gated Ca²⁺ channels (LVGC) were studied with whole-cell patch clamp in cultured vascular smooth muscle cells (VSMCs). The results showed that farrerol significantly induced dose-dependent relaxation on aortic rings, while this vasorelaxation was not affected by N^G-nitro-l-arginine methylester ester or endothelium denudation. In endothelium-denuded aortas, farrerol also reduced Ca²⁺-induced contraction on the basis of the stable contraction induced by KCl or phenylephrine (PE) in Ca²⁺-free solution. Moreover, after incubation with verapamil, farrerol can induce relaxation in endothelium-denuded aortas precontracted by PE, and this effect can be enhanced by ruthenium red, but not by heparin. With laser scanning confocal microscopy method, the farrerol-induced decline of [Ca²⁺]_in in cultured VSMCs was observed. Furthermore, we found that farrerol could suppress Ca²⁺ influx via LVGC by patch clamp technology. These findings suggested that farrerol can regulate the vascular tension and could be developed as a practicable vasorelaxation drug.