Eleutheroside B, a selective late sodium current inhibitor, suppresses atrial fibrillation induced by sea anemone toxin II in rabbit hearts

Integrating serum pharmacochemistry and network pharmacology to explore the molecular mechanisms of Acanthopanax senticosus (Rupr. & Maxim.) Harms on attenuating doxorubicin-induced myocardial injury

ETHNOPHARMACOLOGICAL RELEVANCE

Acanthopanax senticosus (Rupr. & Maxim.) Harms (AS), also known as Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. or Siberian ginseng, has a rich history of use as an adaptogen, a substance believed to increase the body's resistance to stress, fatigue, and infectious diseases. As a traditional Chinese medicine, AS is popular for its cardioprotective effects which can protect the cardiovascular system from hazardous conditions. Doxorubicin (DOX), on the other hand, is a first-line chemotherapeutic agent against a variety of cancers, including breast cancer, lung cancer, gastric cancer, and leukemia, etc. Despite its effectiveness, the clinical use of DOX is limited by its side effects, the most serious of which is cardiotoxicity. Considering AS could be applied as an adjuvant to anticancer agents, the combination of AS and DOX might exert synergistic effects on certain malignancies with mitigated cardiotoxicity. Given this, it is necessary and meaningful to confirm whether AS would neutralize the DOX-induced cardiotoxicity and its underlying molecular mechanisms.

AIM OF THE STUDY

This paper aims to validate the cardioprotective effects of AS against DOX-induced myocardial injury (MI) while deciphering the molecular mechanisms underlying such effects.

MATERIALS AND METHODS

Firstly, the cardioprotective effects of AS against DOX-induced MI were confirmed both in vitro and in vivo. Secondly, serum pharmacochemistry and network pharmacology were orchestrated to explore the in vivo active compounds of AS and predict their ways of functioning in the treatment of DOX-induced MI. Finally, the predicted mechanisms were validated by Western blot analysis during in vivo experiments.

RESULTS

The results demonstrated that AS possessed excellent antioxidative ability, and could alleviate the apoptosis of H9C2 cells and the damage to mitochondria induced by DOX. In vivo experiments indicated that AS could restore the conduction abnormalities and ameliorate histopathological changes according to the electrocardiogram and cardiac morphology. Meanwhile, it markedly downregulated the inflammatory factors (TNF-α, IL-6, and IL-1β), decreased plasma ALT, AST, LDH, CK, CK-MB, and MDA levels, as well as increased SOD and GSH levels compared to the model group, which collectively substantiate the effectiveness of AS. Afterward, 14 compounds were identified from different batches of AS-dosed serum and selected for mechanism prediction through HPLC-HRMS analysis and network pharmacology. Consequently, the MAPKs and caspase cascade were confirmed as primary targets among which the interplay between the JNK/Caspase 3 feedback loop and the phosphorylation of ERK1/2 were highlighted.

CONCLUSIONS

In conclusion, the integrated approach employed in this paper illuminated the molecular mechanism of AS against DOX-induced MI, whilst providing a valuable strategy to elucidate the therapeutic effects of complicated TCM systems more reliably and efficiently.

The characteristics and molecular targets of antiarrhythmic natural products

Arrhythmia is one of the most common cardiovascular diseases. The search for new drugs to suppress various types of cardiac arrhythmias has always been the focus of attention. In the past decade, the screening of antiarrhythmic active substances from plants has received extensive attention. These natural compounds have obvious antiarrhythmic effects, and chemical modifications based on natural compounds have greatly increased their pharmacological properties. The chemical modification of botanical antiarrhythmic drugs is closely related to the development of new and promising drugs. Therefore, the structural characteristics and action targets of natural compounds with antiarrhythmic effects are reviewed in this paper, so that pharmacologists can select antiarrhythmic lead compounds from natural compounds based on the disease target - chemical structural characteristics.

Naringin exerts antiarrhythmic effects by inhibiting channel currents in mouse cardiomyocytes

INTRODUCTION

Naringin, a flavonoid extracted from citrus plants, has a variety of biological effects. Studies have shown that increasing the consumption of flavonoid-rich foods can reduce the incidence of cardiac arrhythmia. Naringin has been reported to have beneficial cardiovascular effects and thus can be used to prevent cardiovascular diseases, but the electrophysiological mechanism through which it prevents arrhythmias has not been elucidated. This study was conducted to investigate the effect of naringin on the transmembrane ion channel currents in mouse ventricular myocytes and the antiarrhythmic effect of this compound on Langendorff-perfused mouse hearts.

METHODS

Action potentials (APs) and ionic currents were recorded in isolated ventricular myocytes using the whole-cell patch-clamp technique. Anemone toxin II (ATX II) and CaCl2 were used to induce early afterdepolarizations (EADs) and delayed afterdepolarizations (DADs), respectively. Electrocardiogram (ECG) recordings were conducted in Langendorff-perfused mouse hearts with a BL-420F biological signal acquisition and analysis system.

RESULTS

At the cellular level, naringin shortened the action potential duration (APD) of ventricular myocytes and decreased the maximum depolarization velocity (Vmax) of APs.Naringin inhibited the L-type calcium current (ICa.L) and ATX II enhanced the late sodium current (INa.L) in a concentration-dependent manner with IC50 values of 508.5 μmol/L (n = 9) and 311.6 μmol/L (n = 10), respectively. In addition, naringin also inhibited the peak sodium current (INa·P) and delayed the rectifier potassium current (IK) and the transient outward potassium current (Ito). Moreover, naringin reduced ATX II-induced APD prolongation and EADs and had a significant inhibitory effect on CaCl2-induced DADs as well. At the organ level, naringin reduced the incidence of ventricular tachycardia (VT) and ventricular fibrillation (VF) induced by ATX II and shortened the duration of both in isolated hearts.

CONCLUSION

Naringin can inhibit the occurrence of EADs and DADs at the cellular level; furthermore, it can inhibit INa.L, ICa.L, INa·P, IK, and Ito in ventricular myocytes. Naringin also inhibits arrhythmias induced by ATX II in hearts. By investigating naringin with this electrophysiological method for the first time, we determined that this flavonoid may be a multichannel blocker with antiarrhythmic effects.

Phenolic Profile, Antioxidant, Anti-Enzymatic and Cytotoxic Activity of the Fruits and Roots of Eleutherococcus senticosus (Rupr. et Maxim.) Maxim

Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. is well-known for its adaptogenic properties in traditional Eastern medicine. It has been categorized as an endangered species due to the over-exploitation of the roots. As a result, alternatives must be found, including the usage of renewable aerial parts such as fruits. The goal of this research was to determine the phenolic compounds and the enzymatic, antioxidant, and cytotoxic activities of the intractum gained from the E. senticosus fruits and the mixture of chloroform-methanol roots extract with naringenin (3:7:5). The obtained results showed, that the intractum contained 1.02 mg/g ext. of polyphenols, 0.30 mg/g ext. of flavonoids, and 0.19 mg/g ext. of phenolic acids. In turn, the mixture of chloroform-methanol roots extract with naringenin (3:7:5) contained 159.27 mg/g ext. of polyphenols, 137.47 mg/g ext. of flavonoids, and 79.99 mg/g ext. of phenolic acids. Regarding the anti-enzymatic assay, the IC₅₀ values for tyrosinase and hyaluronidase were equal to 586.83 and 217.44 [μg/mL] for the intractum, and 162.56 and 44.80 [μg/mL] for the mixture, respectively. Both preparations have possessed significant antioxidant activity in the ABTS, DPPH, and ferrozine tests. No cytotoxic effect on the FaDu and HEP G2 cancer cell lines was observed. Our findings support the traditional use of fruits and roots. Moreover, the results indicate also that adaptogens are rather nontoxic for normal and cancer cells, which corresponds with some hypotheses on adaptogens activity.

Tea saponin additive to extract eleutheroside B and E from Eleutherococcus senticosus by ultrasonic mediation and its application in a semi-pilot scale

The safety of ethanol in operations and its effects on human health are gradually being questioned. Under this premise, we attempted to use the natural surfactant tea saponin, which originates from the processing residues of camellia oil, as the additive of the extraction solvent and to extract eleutheroside B and eleutheroside E in the roots and rhizomes of E. senticosus by ultrasonic mediation. After a single-factor experiment, extraction kinetics at different powers and reaction temperatures, and Box-Behnken design optimization, the optimal conditions obtained were 0.3% tea saponin solution as the extraction solvent, 20 mL/g liquid-solid ratio, 250 W ultrasonic irradiation power (43.4 mW/g ultrasonic power density) and 40 min ultrasonic irradiation time. Under optimal conditions, satisfactory yields of eleutheroside B (1.06 ± 0.04 mg/g) and eleutheroside E (2.65 ± 0.12 mg/g) were obtained with semi pilot scale ultrasonic extraction equipment. The experiments showed that compared with the traditional thermal extraction process, the extraction time is significantly reduced at lower operating temperatures.

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.

Effects of Normoxic Recovery on Intima-Media Thickness of Aorta and Pulmonary Artery Following Intermittent Hypoxia in Mice

Obstructive sleep apnea (OSA) patients are at risk for increased blood pressure and carotid intima-media thickness (IMT), with pulmonary hypertension and right-sided heart failure potentially developing as well. Chronic intermittent hypoxia (IH) has been used as an OSA model in animals, but its effects on vascular beds have not been evaluated using objective unbiased tools. Previously published and current experimental data in mice exposed to IH were evaluated for IMT in aorta and pulmonary artery (PA) after IH with or without normoxic recovery using software for meta-analysis, Review Manager 5. Because IMT data reports on PA were extremely scarce, atherosclerotic area percentage from lumen data was also evaluated. IH significantly increased IMT parameters in both aorta and PA as illustrated by Forest plots (P < 0.01), which also confirmed that IMT values after normoxic recovery were within the normal range in both vascular beds. One-sided scarce lower areas in Funnel Plots were seen for both aorta and PA indicating the likelihood of significant publication bias. Forest and Funnel plots, which provide unbiased assessments of published and current data, suggest that IH exposures may induce IMT thickening that may be reversed by normoxic recovery in both aorta and PA. In light of the potential likelihood of publication bias, future studies are needed to confirm or refute the findings. In conclusion, OSA may induce IMT thickening (e.g., aorta and/or PA), but the treatment (e.g., nasal continuous positive airway pressure) will likely lead to improvements in such findings.