Sophocarpine Attenuates the Na+-dependent Ca2+ Overload Induced by Anemonia Sulcata Toxin—Increased Late Sodium Current in Rabbit Ventricular Myocytes:

Prevention and control of cardiac arrhythmic by using therapeutic foods: A review

INTRODUCTION

Arrhythmia occurs as a common heart vascular disease. Functional food is a rich source of natural compounds with significant pharmacological, The aim of this paper is to explore its effect on arrhythmia.

METHODS

By reviewing the literature and summarising the findings, we described the role of functional foods in the alleviation of cardiac arrhythmias from different perspectives.

RESULTS

Our study shows that functional foods have anti-arrhythmic effects through modulation of ion channels, oxidative stress, and Calmodulin-dependent protein kinase II.

CONCLUSIONS

We summarize the mechanism of arrhythmia inhibition by the active ingredients of medicinal diets in this review article, intending to provide research ideas for dietary therapy to regulate arrhythmia.

Sophorae tonkinensis radix et rhizoma: A comprehensive review of the ethnopharmacology, phytochemistry, pharmacology, pharmacokinetics, toxicology and detoxification strategy

ETHNOPHARMACOLOGICAL RELEVANCE

Sophorae tonkinensis Radix et Rhizoma (STR), the dried root and rhizome of Sophora tonkinensis Gagnep., is commonly used in the treatment of tonsillitis and pharyngitis, throat soreness and throat obstruction, swelling and aching of gum, etc. in China or other Asian countries. STR is usually used as the core herb in traditional Chinese medicine preparations, such as "Biyanling Tablets", "Fufang Muji Granules" and "Ganyanling Injections", etc. AIM OF THE REVIEW: This review aimed to provide a comprehensive analysis of STR in terms of botany, traditional use, phytochemistry, ethnopharmacology, pharmacology, pharmacokinetics, toxicology and detoxification strategy, to provide a rational application in future research.

MATERIALS AND METHODS

The information involved in the study was gathered from a variety of electronic resources, including China National Knowledge Infrastructure (CNKI), SciFinder, Google Scholar, PubMed, Web of Science, and Chinese Masters and Doctoral Dissertations.

RESULTS

Till now, a total of 333 chemical components have been identified in STR, including 85 alkaloids, 124 flavonoids, 24 triterpenes, 27 triterpene saponins, 34 organic acids, 8 polysaccharides, etc. STR and its main active constituents have cardiovascular protection, anti-tumor activity, anti-inflammatory activity, antipyretic activity, analgesic activity, antibacterial activity, antifungal activity, antiviral activity, and hepatoprotective activity, etc. However, toxic effects of STR on the liver, nerves, heart, and gastrointestinal tract have also been observed. To mitigate these risks, STR needs attenuation before use, with the most common detoxification methods being processing and combined use with other drugs. The pharmacokinetics of STR in vivo and traditional and clinical prescriptions containing STR have been sorted out. Despite the potential therapeutic benefits of STR, further research is warranted to elucidate its hepatotoxicity, particularly in vivo, exploring aspects such as in vivo metabolism, distribution, and mechanisms.

CONCLUSION

This review serves to emphasize the therapeutic potential of STR and highlights the crucial need to address its toxicity concerns before considering clinical application. Further research is required to comprehensively investigate the toxicological properties of STR, with particular emphasis on its hepatotoxicity and neurotoxicity. Such research endeavors have the potential to standardize the rational application of STR for optimal therapeutic outcomes.

A review on the pharmacology, pharmacokinetics and toxicity of sophocarpine

Sophocarpine is a natural compound that belongs to the quinolizidine alkaloid family, and has a long history of use and widespread distribution in traditional Chinese herbal medicines such as Sophora alopecuroides L., Sophora flavescens Ait., and Sophora subprostrata. This article aims to summarize the pharmacology, pharmacokinetics, and toxicity of sophocarpine, evaluate its potential pharmacological effects in various diseases, and propose the necessity for further research and evaluation to promote its clinical application. A large number of studies have shown that it has anti-inflammatory, analgesic, antiviral, antiparasitic, anticancer, endocrine regulatory, and organ-protective effects as it modulates various signaling pathways, such as the NF-κB, MAPK, PI3K/AKT, and AMPK pathways. The distribution of sophocarpine in the body conforms to a two-compartment model, and sophocarpine can be detected in various tissues with a relatively short half-life. Although the pharmacological effects of sophocarpine have been confirmed, toxicity and safety assessments and reports on molecular mechanisms of its pharmacological actions have been limited. Given its significant pharmacological effects and potential clinical value, further research and evaluation are needed to promote the clinical application of sophocarpine.

Natural products as the calcium channel blockers for the treatment of arrhythmia: Advance and prospect

Arrhythmia is one of the commonly heart diseases with observed abnormal heart-beat rhythm that caused by the obstacles of cardiac activity and conduction. The arrhythmic pathogenesis is complex and capricious and related with other cardiovascular diseases that may lead to heart failure and sudden death. In particular, calcium overload is recognized as the main reason causing arrhythmia through inducing apoptosis in cardiomyocytes. Moreover, calcium channel blockers have been widely used as the routine drugs for the treatment of arrhythmia, but the different arrhythmic complications and adverse effects limit their further applications and demand new drug discovery. Natural products have always been the rich minerals for the development of new drugs that could be employed as the versatile player for the discovery of safe and effective anti-arrhythmia drugs with new mechanisms. In this review, we summarized natural products with the activity against calcium signaling and the relevant mechanism of actions. We are expected to provide an inspiration for the pharmaceutical chemists to develop more potent calcium channel blockers for the treatment of arrhythmia.

Pharmacological mechanism of natural drugs and their active ingredients in the treatment of arrhythmia via calcium channel regulation

Arrhythmia is characterized by abnormal heartbeat rhythms and frequencies caused by heart pacing and conduction dysfunction. Arrhythmia is the leading cause of death in patients with cardiovascular disease, with high morbidity and mortality rates, posing a serious risk to human health. Natural drugs and their active ingredients, such as matrine(MAT), tetrandrine(TET), dehydroevodiamine, tanshinone IIA, and ginsenosides, have been widely used for the treatment of atrial fibrillation, ventricular ectopic beats, sick sinus syndrome, and other arrhythmia-like diseases owing to their unique advantages. This review summarizes the mechanism of action of natural drugs and their active ingredients in the treatment of arrhythmia via the regulation of Ca²⁺, such as alkaloids, quinones, saponins, terpenoids, flavonoids, polyphenols, and lignan compounds, to provide ideas for the innovative development of natural drugs with potential antiarrhythmic efficacy.

Discovery, Topo I inhibitory activity and mechanism evaluation of two novel cytisine-type alkaloid dimers from the seeds of Sophora alopecuroides L

Alopecurosines A and B (CMs 1 and 2, respectively) are two novel cytisine-type alkaloid dimers first isolated from the aerial parts of Sophora alopecuroides L. CMs 1 and 2 are new dimeric alkaloids whose piperidine matrine ring is cleaved and connected via the N'-1 bond. Their chemical structures have been confirmed by IR, UV, HR-ESI-MS, and NMR. Preliminary screening shows that they have topoisomerase I (Topo I)-based anti-tumor activity. Their Topo I inhibitory activities and mechanism have been evaluated by agarose gel electrophoresis assay and a molecular docking study. The results show that the inhibition rate of CM 1 is 82.26% at 1 mM concentration and that it exhibits significantly Topo I inhibitory activity. Further research has illustrated that CMs 1 and 2 exert inhibitory activity by stabilising the Topo I-DNA cleavage complex, implying that they have the potential to be developed as novel Topo I inhibitors.

Late Sodium Current of the Heart: Where Do We Stand and Where Are We Going?

Late sodium current has long been linked to dysrhythmia and contractile malfunction in the heart. Despite the increasing body of accumulating information on the subject, our understanding of its role in normal or pathologic states is not complete. Even though the role of late sodium current in shaping action potential under physiologic circumstances is debated, it’s unquestioned role in arrhythmogenesis keeps it in the focus of research. Transgenic mouse models and isoform-specific pharmacological tools have proved useful in understanding the mechanism of late sodium current in health and disease. This review will outline the mechanism and function of cardiac late sodium current with special focus on the recent advances of the area.

Quinolizidine alkaloids derivatives from Sophora alopecuroides Linn: Bioactivities, structure-activity relationships and preliminary molecular mechanisms

Quinolizidine alkaloids, as essential active ingredients extracted from Sophora alopecuroides Linn, have been well concerned in the past several decades owing to the unique structural features and numerous pharmacological activities. Quinolizidine alkaloids consist of matrine, oxymatrine, sophoridine, sophocarpine and aloperine etc. Additionally, quinolizidine alkaloids exert various excellent activities, including anti-cancer, anti-inflammation, anti-fibrosis, anti-virus and anti-arrhythmia regulations. In this review, we comprehensively clarify the pharmacological activities of quinolizidine alkaloids, as well as the relationship between biological function and structure-activity of substituted quinolizidine alkaloids. We believe that biological agents based on the pharmacological functions of quinolizidine alkaloids could be well applied in clinical practice.

Sophocarpine Suppresses NF-κB-Mediated Inflammation Both In Vitro and In Vivo and Inhibits Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is a leading cause of mortality in patients with diabetes. DCM is a leading cause of mortality in patients with diabetes. We used both in vitro and in vivo experiments to investigate the hypothesis that sophocarpine (SPC), a natural quinolizidine alkaloid derived from a Chinese herb, could protect against DCM. We used hyperglycemic myocardial cells and a streptozotocin (STZ)-induced type 1 diabetes mellitus mouse model. SPC protected myocardial cells from hyperglycemia-induced injury by improving mitochondrial function, suppressing inflammation, and inhibiting cardiac apoptosis. The SPC treatment significantly inhibited the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in high-glucose-stimulated inflammatory responses. Moreover, SPC significantly slowed the development and progression of DCM in STZ-induced diabetic mice. These results show that SPC suppresses NF-κB-mediated inflammation both in vitro and in vivo and may be used to treat DCM.

Andrographolide inhibits arrhythmias and is cardioprotective in rabbits

Andrographolide has a protective effect on the cardiovascular system. To study its cardic-electrophysiological effects, action potentials and voltage-gated Na⁺ (I_Na), Ca²⁺ (I_CaL), and K⁺ (I_K1, I_Kr, I_to and I_Kur) currents were recorded using whole-cell patch clamp and current clamp techniques. Additionally, the effects of andrographolide on aconitine-induced arrhythmias were assessed on electrocardiograms in vivo. We found that andrographolide shortened action potential duration and reduced maximum upstroke velocity in rabbit left ventricular and left atrial myocytes. Andrographolide attenuated rate-dependence of action potential duration, and reduced or abolished delayed afterdepolarizations and triggered activities induced by isoproterenol (1 μM) and high calcium ([Ca²⁺]_o=3.6 mM) in left ventricular myocytes. Andrographolide also concentration-dependently inhibited I_Na and I_CaL, but had no effect on I_to, I_Kur, I_K1, or I_Kr in rabbit left ventricular and left atrial myocytes. Andrographolide treatment increased the time and dosage thresholds of aconitine-induced arrhythmias, and reduced arrhythmia incidence and mortality in rabbits. Our results indicate that andrographolide inhibits cellular arrhythmias (delayed afterdepolarizations and triggered activities) and aconitine-induced arrhythmias in vivo, and these effects result from I_Na and I_CaL inhibition. Andrographolide may be useful as a class I and IV antiarrhythmic therapeutic.

Inhibition of late sodium current suppresses calcium-related ventricular arrhythmias by reducing the phosphorylation of CaMK-II and sodium channel expressions

Cardiac arrhythmias associated with intracellular calcium inhomeostasis are refractory to antiarrhythmic therapy. We hypothesized that late sodium current (I _Na) contributed to the calcium-related arrhythmias. Monophasic action potential duration at 90% completion of repolarization (MAPD₉₀) was significantly increased and ventricular arrhythmias were observed in hearts with increased intracellular calcium concentration ([Ca²⁺]_i) by using Bay K 8644, and the increase became greater in hearts treated with a combination of ATX-II and Bay K 8644 compared to Bay K 8644 alone. The prolongations caused by Bay K 8644 and frequent episodes of ventricular tachycardias, both in absence and presence of ATX-II, were significantly attenuated or abolished by late I _Na inhibitors TTX and eleclazine. In rabbit ventricular myocytes, Bay K 8644 increased I _CaL density, calcium transient and myocyte contraction. TTX and eleclazine decreased the amplitude of late I _Na, the reverse use dependence of MAPD₉₀ at slower heart rate, and attenuated the increase of intracellular calcium transient and myocyte contraction. TTX diminished the phosphorylation of CaMKII-δ and Na_v 1.5 in hearts treated with Bay K 8644 and ATX-II. In conclusion, late I _Na contributes to ventricular arrhythmias and its inhibition is plausible to treat arrhythmias in hearts with increased [Ca²⁺]_i.

The Role of Biologically Active Ingredients from Natural Drug Treatments for Arrhythmias in Different Mechanisms

Arrhythmia is a disease that is caused by abnormal electrical activity in the heart rate or rhythm. It is the major cause of cardiovascular morbidity and mortality. Although several antiarrhythmic drugs have been used in clinic for decades, their application is often limited by their adverse effects. As a result, natural drugs, which have fewer side effects, are now being used to treat arrhythmias. We searched for all articles on the role of biologically active ingredients from natural drug treatments for arrhythmias in different mechanisms in PubMed. This study reviews 19 natural drug therapies, with 18 active ingredient therapies, such as alkaloids, flavonoids, saponins, quinones, and terpenes, and two kinds of traditional Chinese medicine compound (Wenxin-Keli and Shensongyangxin), all of which have been studied and reported as having antiarrhythmic effects. The primary focus is the proposed antiarrhythmic mechanism of each natural drug agent. Conclusion. We stress persistent vigilance on the part of the provider in discussing the use of natural drug agents to provide a solid theoretical foundation for further research on antiarrhythmia drugs.

Tolterodine reduces veratridine-augmented late INa, reverse-INCX and early afterdepolarizations in isolated rabbit ventricular myocytes

AIM

The augmentation of late sodium current (I_Na.L) not only causes intracellular Na⁺ accumulation, which results in intracellular Ca²⁺ overload via the reverse mode of the Na⁺/Ca²⁺ exchange current (reverse-I_NCX), but also prolongs APD and induces early afterdepolarizations (EAD), which can lead to arrhythmia and cardiac dysfunction. Thus, the inhibition of I_Na.L is considered to be a potential way for therapeutic intervention in ischemia and heart failure. In this study we investigated the effects of tolterodine (Tol), a competitive muscarinic receptor antagonist, on normal and veratridine (Ver)-augmented I_Na.L, reverse-I_NCX and APD in isolated rabbit ventricular myocytes, which might contribute to its cardioprotective activity.

METHODS

Rabbit ventricular myocytes were prepared. The I_Na.L and reverse-I_NCX were recorded in voltage clamp mode, whereas action potentials and Ver-induced early afterdepolarizations (EADs) were recorded in current clamp mode. Drugs were applied via superfusion.

RESULTS

Tol (3-120 nmol/L) concentration-dependently inhibited the normal and Ver-augmented I_Na.L with IC₅₀ values of 32.08 nmol/L and 42.47 nmol/L, respectively. Atropine (100 μmol/L) did not affect the inhibitory effects of Tol (30 nmol/L) on Ver-augmented I_Na.L. In contrast, much high concentrations of Tol was needed to inhibit the transient sodium current (I_Na.T) with an IC₅₀ value of 183.03 μmol/L. In addition, Tol (30 nmol/L) significantly shifted the inactivation curve of I_Na.T toward a more depolarizing membrane potential without affecting its activation characteristics. Moreover, Tol (30 nmol/L) significantly decreased Ver-augmented reverse-I_NCX. Tol (30 nmol/L) increased the action potential duration (APD) by 16% under the basal conditions. Ver (20 μmol/L) considerably extended the APD and evoked EADs in 18/24 cells (75%). In the presence of Ver, Tol (30 nmol/L) markedly decreased the APD and eliminated EADs (0/24 cells).

CONCLUSION

Tol inhibits normal and Ver-augmented I_NaL and decreases Ver-augmented reverse-I_NCX. In addition, Tol reverses the prolongation of the APD and eliminates the EADs induced by Ver, thus prevents Ver-induced arrhythmia.

Differentiation therapy of hepatocellular carcinoma by inhibiting the activity of AKT/GSK-3β/β-catenin axis and TGF-β induced EMT with sophocarpine

Hepatocellular carcinoma progression is thought to be driven by cancer stem cells (CSCs). No clinical trial has, as yet, shown convincing long-term disease free survival results for the majority of patients in HCC. So it is important to discover new anti-cancer agents. In our study, we chose sophocarpine, which is derived from the foxtail-like sophora herb, for its efficacy to inhibit HCC including CSCs and potential mechanism study. Our results show that sophocarpine could not only reduce HCC cell viability, eliminate HCC and reverse hepatoma cells malignant phenotype, but also reduce the ratio of CSCs and inhibit the sphere formation of CSCs in vitro. In vivo, sophocarpine significantly displayed antitumor effects in subcutaneous xenograft HCC models and orthotopic transplantation tumor models. Further studies showed that sophocarpine could exert anti-tumor effects partly via downregulating the activity of the cancer stem cell related pathways and inhibiting EMT induced by TGF-β.

Ketamine attenuates the Na+-dependent Ca2+ overload in rabbit ventricular myocytes in vitro by inhibiting late Na+ and L-type Ca2+ currents

AIM

Intracellular Ca(2+) ([Ca(2+)]i) overload occurs in myocardial ischemia. An increase in the late sodium current (INaL) causes intracellular Na(+) overload and subsequently [Ca(2+)]i overload via the reverse-mode sodium-calcium exchanger (NCX). Thus, inhibition of INaL is a potential therapeutic target for cardiac diseases associated with [Ca(2+)]i overload. The aim of this study was to investigate the effects of ketamine on Na(+)-dependent Ca(2+) overload in ventricular myocytes in vitro.

METHODS

Ventricular myocytes were enzymatically isolated from hearts of rabbits. INaL, NCX current (INCX) and L-type Ca(2+) current (ICaL) were recorded using whole-cell patch-clamp technique. Myocyte shortening and [Ca(2+)]i transients were measured simultaneously using a video-based edge detection and dual excitation fluorescence photomultiplier system.

RESULTS

Ketamine (20, 40, 80 μmol/L) inhibited INaL in a concentration-dependent manner. In the presence of sea anemone toxin II (ATX, 30 nmol/L), INaL was augmented by more than 3-fold, while ketamine concentration-dependently suppressed the ATX-augmented INaL. Ketamine (40 μmol/L) also significantly suppressed hypoxia or H2O2-induced enhancement of INaL. Furthermore, ketamine concentration-dependently attenuated ATX-induced enhancement of reverse-mode INCX. In addition, ketamine (40 μmol/L) inhibited ICaL by 33.4%. In the presence of ATX (3 nmol/L), the rate and amplitude of cell shortening and relaxation, the diastolic [Ca(2+)]i, and the rate and amplitude of [Ca(2+)]i rise and decay were significantly increased, which were reverted to control levels by tetrodotoxin (TTX, 2 μmol/L) or by ketamine (40 μmol/L).

CONCLUSION

Ketamine protects isolated rabbit ventricular myocytes against [Ca(2+)]i overload by inhibiting INaL and ICaL.

Protein kinase C and Ca(2+) -calmodulin-dependent protein kinase II mediate the enlarged reverse INCX induced by ouabain-increased late sodium current in rabbit ventricular myocytes

NEW FINDINGS

What is the central question of this study? What are the effects of protein kinase C (PKC) and Ca(2+) -calmodulin-dependent protein kinase II (CaMKII) on late sodium current (INaL ), reverse Na(+) -Ca(2+) exchange current (reverse INCX ) or intracellular Ca(2+) levels changed by ouabain? What is the main finding and its importance? Ouabain, even at low concentrations (0.5-8.0 μm), can increase INaL and reverse INCX , and these effects may contribute to the effect of the glycoside to increase Ca(2+) transients and contractility. Both PKC and CaMKII activities may mediate or modulate these processes. It has been reported that the cardiac glycoside ouabain can increase the late sodium current (INaL ), as well as the diastolic intracellular calcium concentration and contractile shortening. Whether an increase of INaL participates in a pathway that can mediate the positive inotropic response to ouabain is unknown. We therefore determined the effects of ouabain on INaL , reverse Na(+) -Ca(2+) exchange current (reverse INCX ), intracellular Ca(2+) ([Ca(2+) ]i ) levels and contractile shortening in rabbit isolated ventricular myocytes. Ouabain (0.1-8 μm) markedly increased INaL and reverse INCX in a concentration-dependent manner, with significant effects at concentrations as low as 0.5 and 1 μm. These effects of ouabain were suppressed by the INaL inhibitors TTX and ranolazine, the protein kinase C inhibitor bisindolylmaleimide and the Ca(2+) -calmodulin-dependent protein kinase II inhibitor KN-93. The enhancement by 0.5 μm ouabain of ventricular myocyte contractility and intracellular Ca(2+) transients was suppressed by 2.0 μm TTX. We conclude that ouabain, even at low concentrations (0.5-8.0 μm), can increase INaL and reverse INCX , and these effects may contribute to the effect of the glycoside to increase Ca(2+) transients and contractility. Both protein kinase C and Ca(2+) -calmodulin-dependent protein kinase II activities may mediate or modulate these processes.

New antiarrhythmic targets to control intracellular calcium handling

Sudden cardiac death due to ventricular arrhythmias is a major problem. Drug therapies to prevent SCD do not provide satisfying results, leading to the demand for new antiarrhythmic strategies. New targets include Ca²⁺/Calmodulin-dependent protein kinase II (CaMKII), the Na/Ca exchanger (NCX), the Ryanodine receptor (RyR, and its associated protein FKBP12.6 (Calstabin)) and the late component of the sodium current (I_Na-Late), all related to intracellular calcium (Ca²⁺) handling. In this review, drugs interfering with these targets (SEA-0400, K201, KN-93, W7, ranolazine, sophocarpine, and GS-967) are evaluated and their future as clinical compounds is considered. These new targets prove to be interesting; however more insight into long-term drug effects is necessary before clinical applicability becomes reality.

Resveratrol attenuates the Na(+)-dependent intracellular Ca(2+) overload by inhibiting H(2)O(2)-induced increase in late sodium current in ventricular myocytes

Background/Aims

Resveratrol has been demonstrated to be protective in the cardiovascular system. The aim of this study was to assess the effects of resveratrol on hydrogen peroxide (H₂O₂)-induced increase in late sodium current (I_Na.L) which augmented the reverse Na⁺-Ca²⁺ exchanger current (I_NCX), and the diastolic intracellular Ca²⁺ concentration in ventricular myocytes.

Methods

I_Na.L, I_NCX, L-type Ca²⁺ current (I_Ca.L) and intracellular Ca²⁺ properties were determined using whole-cell patch-clamp techniques and dual-excitation fluorescence photomultiplier system (IonOptix), respectively, in rabbit ventricular myocytes.

Results

Resveratrol (10, 20, 40 and 80 µM) decreased I_Na.L in myocytes both in the absence and presence of H₂O₂ (300 µM) in a concentration dependent manner. Ranolazine (3–9 µM) and tetrodotoxin (TTX, 4 µM), I_Na.L inhibitors, decreased I_Na.L in cardiomyocytes in the presence of 300 µM H₂O₂. H₂O₂ (300 µM) increased the reverse I_NCX and this increase was significantly attenuated by either 20 µM resveratrol or 4 µM ranolazine or 4 µM TTX. In addition, 10 µM resveratrol and 2 µM TTX significantly depressed the increase by 150 µM H₂O₂ of the diastolic intracellular Ca²⁺ fura-2 fluorescence intensity (FFI), fura-fluorescence intensity change (△FFI), maximal velocity of intracellular Ca²⁺ transient rise and decay. As expected, 2 µM TTX had no effect on I_Ca.L.

Conclusion

Resveratrol protects the cardiomyocytes by inhibiting the H₂O₂-induced augmentation of I_Na.L.and may contribute to the reduction of ischemia-induced lethal arrhythmias.