Anti-arrhythmia potential of honey-processed licorice in zebrafish model: Antioxidant, histopathological and tissue distribution

ETHNOPHARMACOLOGICAL RELEVANCE

Honey-processed licorice (HPL) is the roasted product of licorice. It is recorded in the "Shang Han Lun" that licorice has better protection on heart after honey-processed. However, researches regarding its protective effect on the heart and the distribution of HPL in vivo are still limited.

AIM OF THE STUDY

To evaluate the cardio-protection of HPL and explore the law of ten main components distribution in vivo under physiological and pathological conditions for an attempt to clarify the pharmacological substance basis of HPL in treating arrhythmia.

MATERIALS AND METHODS

The adult zebrafish arrhythmia model was established by doxorubicin (DOX). Electrocardiogram (ECG) was used to detect the heart rate changes of zebrafish. SOD and MDA assays were used to evaluate oxidative stress levels in the myocardium. HE staining was used to observe the morphological change of myocardial tissues after HPL treatment. The UPLC-MS/MS was adapted to detect the content of ten main components of HPL in heart, liver, intestine, and brain under normal and heart injury conditions.

RESULTS

Heart rate of zebrafish was decreased, the SOD activity was attenuated and MDA content was increased in myocardium after administration of DOX. Moreover, tissue vacuolation and inflammatory infiltration were detected in zebrafish myocardium induced by DOX. HPL could ameliorate heart injury and bradycardia induced by DOX to a certain extent by increasing SOD activity and reducing MDA content. In addition, the study of tissue distribution revealed that the content of liquiritin, isoliquiritin, and isoliquiritigenin in the heart was higher in the presence of arrhythmias than those in the normal condition. Under pathological conditions, the heart highly exposed to these three components could elicit anti-arrhythmic effects by regulating immunity and oxidation.

CONCLUSION

These findings indicate that the HPL is protective against heart injury induced by DOX, and its effect is associated with the alleviation of oxidative stress and tissue injury. And the cardioprotective effect of HPL under pathological conditions may be related to the high distribution of liquiritin, isoliquiritin, and isoliquiritigenin in heart tissue. This study provides an experimental basis for the cardioprotective effects and tissue distribution of HPL.

Effectiveness of Hepatoprotectors in the Practice of a Family Doctor

Hepatoprotectors – drugs that form the basis of pathogenetic treatment of various liver diseases. They help restore impaired hepatocyte function, increase the resistance of liver cells to the effects of pathological factors, enhance the detoxification function of hepatocytes, have antioxidant properties. There is no generally accepted classification of hepatoprotectors today, they are divided into several groups depending on the origin: plant, animal, synthetic origin, products containing essential phospholipids, amino acids, vitamins, and other groups. One of the well-known hepatoprotectors of plant origin is glycyrrhizin – the main active ingredient of licorice root. Licorice root (Glycyrrhiza glabra) is a drug used in medicine since ancient times, as evidenced by historical data from China, Japan, India, Greece, and Europe. Licorice root is widely used today in medicine and the food industry. Glycyrrhizin – potassium and calcium salt of glycyrrhizinic acid, has a wide range of properties. It is used mainly for the treatment of chronic liver disease. In non-alcoholic fatty liver disease, the use of glycyrrhizin helps reduce steatosis, inflammation in the liver has an antifibrotic effect. Studies on the use of glycyrrhizinic acid in hepatocellular carcinoma are actively conducted, as its antitumor properties are known. It is included in the treatment of chronic viral hepatitis. In vitro studies have shown the antiviral activity of glycyrrhizin against HIV-1, SARS-associated virus, respiratory syncytial virus, arboviruses, and its potential for coronavirus control is being discussed. Possibilities of application of glycyrrhizin and cardiovascular diseases are studied. In this article, we present a review of current literature data on glycerol, its properties, and applications in liver disease, other diseases, and our own clinical observations.

18β-Glycyrrhetinic Acid Improves Cardiac Diastolic Function by Attenuating Intracellular Calcium Overload

Ranolazine, a late sodium current inhibitor, has been demonstrated to be effective on heart failure. 18β-glycyrrhetinic acid (18β-GA) has the similar inhibitory effect on late sodium currents. However, its effect on diastolic function is still unknown. This study aimed to determine whether 18β-GA can improve the diastolic function and to explore the underlying mechanisms. Eighty male Sprague Dawley (SD) rats of Langendorff model were randomly divided into the following groups: group A, normal cardiac perfusion group; group B, ischemia-reperfusion group; group C, ischemia-reperfusion with anemoniasulcata toxin II (ATX-II); group D, ranolazine group; and group E, 18β-GA group with four different concentrations. Furthermore, a pressure-overloaded rat model induced by trans-aortic constriction (TAC) was established. Echocardiography and hemodynamics were used to evaluate diastolic function at 14th day after TAC. Changes of free intracellular calcium (Ca²⁺) concentration was indirectly detected by laser scanning confocal microscope to confirm the inhibition of late sodium currents. With the intervention of ATX-II on ischemia reperfusion injury group, 5 µmol/L ranolazine, and 5, 10, 20, 40 µmol/L 18β-GA could improve ATX-II-induced cardiac diastolic dysfunction. 630 mg/kg glycyrrhizin tablets could improve cardiac diastolic function in the pressure-overloaded rats. 18β-GA and ranolazine had similar effects on reducing the free calcium in cardiomyocytes. The study demonstrates that 18β-GA and glycyrrhizin could improve diastolic dysfunction induced by ischemia-reperfusion injury in Langendorff-perfused rat hearts and pressure-overloaded rats. The mechanism may be attributed to the inhibition of enhanced late sodium currents.

Glycyrrhiza glabra L. (Fabaceae/Leguminosae)

Liquorice is a perennial, temperate-zone herb or subshrub, native of India, Pakistan and southern Europe; also cultivated in England, Belgium, France, Germany, Spain, Italy, Greece, Turkey, Russia, South Africa, Egypt, Syria and Iraq. It has also been grown experimentally in the United States. Ancient historical manuscripts from China, India and Greece mention its use for symptoms of viral respiratory tract infections and hepatitis. The plant has also been described by Theophrastus. Licorice from Egypt has been described to be the best, followed by from Iraq and Syria; the root should be decorticated before use. It concocts viscid humours in diseases of liver, bladder and lungs, and expectorates them. It has been used in Iranian herbal medicine for skin eruptions, including dermatitis, eczema, pruritus and cysts, and for treatment of stomach disorders including peptic ulcers. The herb extract inhibits gastric motility in vivo, which is regarded to be an important aspect for its antiulcer activity. Licorice possesses both anti-inflammatory and antiulcer activities; whereas most anti-inflammatory agents are ulcerogenic. Former German Commission E believed it to be effective in the treatment of atopic dermatitis. Licorice root has been used for years to regulate gastrointestinal function in TCM, has been used for generations as an antidote, demulcent, and elixir in folk medicine of China, and is the most commonly used crude drug in Kampo Medicines, the Japanese form of modified TCM, for the treatment of peptic ulcer. Roots contain glycyrrhizin, the main water-soluble constituent that is 50× sweeter than sugar, 2-β-glucuronosyl glucuronic acid, and isoliquiritigenin-4-glucoside. Glycyrrhizin is a nonhemolytic saponin with foaming property, and one of the most potent hydroxyl radical scavengers. No significant effect of deglycyrrhizinised liquorice was observed on gastric ulcer in an RCT of British patients. Treatment of healthy men with licorice for one-week decreased salivary testosterone values by 26% but no significant decrease in free testosterone, and nine healthy women treated with licorice daily for two cycles, had their mean total serum testosterone decreased by 37% at the end of 2nd month. This property could be useful as an adjunct therapy of hirsutism and PCOS.

Cardioprotective effects of glycyrrhizic acid involve inhibition of calcium influx via L-type calcium channels and myocardial contraction in rats

Glycyrrhizic acid (GA) is one of the main active components in licorice and has often been reported to have cardioprotective effects. However, the underlying cellular mechanisms remain unclear. The aim of this study is to verify the protective effects of GA against isoproterenol (ISO)-induced myocardial ischemia injury in rats. Another aim is to explore the cellular mechanisms based on the L-type Ca²⁺ channel, myocardial cell contraction, and intracellular Ca²⁺ ([Ca²⁺]_i) transient. The results show that GA reduced the ST segment elevation, decreased the heart rate, prevented ISO-induced QT-interval shortening, improved heart morphology, and decreased the activity of CK and LDH. GA blocked I_Ca-L in a dose-dependent manner. The concentration for 50% of the maximal effect (EC₅₀) of GA was 145.54 μg/mL, and the maximal inhibition was 47.43 ± 0.75% at 1000 μg/mL. However, GA did not affect the dynamical properties of the Ca²⁺ channel. GA reversibly reduced the amplitude of cell contraction in a dose-dependent manner and slowed down its deflection and recovery, as well as the [Ca²⁺]_i transient. The data demonstrate that GA inhibits L-type Ca²⁺ channels, decreases the [Ca²⁺]_i transient, and shows a negative cardiac inotropic effect in the ventricular myocardial cells of adult rats. It also protects the myocardia from ischemia injury induced by ISO.

Bioactive Candy: Effects of Licorice on the Cardiovascular System

Licorice, today chiefly utilized as a flavoring additive in tea, tobacco and candy, is one of the oldest used herbs for medicinal purposes and consists of up to 300 active compounds. The main active constituent of licorice is the prodrug glycyrrhizin, which is successively converted to 3β-monoglucuronyl-18β-glycyrrhetinic acid (3MGA) and 18β-glycyrrhetinic acid (GA) in the intestines. Despite many reported health benefits, 3MGA and GA inhibit the 11-β-hydrogenase type II enzyme (11β-HSD2) oxidizing cortisol to cortisone. Through activation of mineralocorticoid receptors, high cortisol levels induce a mild form of apparent mineralocorticoid excess in the kidney and increase systemic vascular resistance. Continuous inhibition of 11β-HSD2 related to excess licorice consumption will create a state of hypernatremia, hypokalemia and increased fluid volume, which can cause serious life-threatening complications especially in patients already suffering from cardiovascular diseases. Two recent meta-analyses of 18 and 26 studies investigating the correlation between licorice intake and blood pressure revealed statistically significant increases both in systolic (5.45 mmHg) and in diastolic blood pressure (3.19/1.74 mmHg). This review summarizes and evaluates current literature about the acute and chronic effects of licorice ingestion on the cardiovascular system with special focus on blood pressure. Starting from the molecular actions of licorice (metabolites) inside the cells, it describes how licorice intake is affecting the human body and shows the boundaries between the health benefits of licorice and possible harmful effects.

Systems Pharmacology Dissection of Traditional Chinese Medicine Wen-Dan Decoction for Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVDs) have been recognized as first killer of human health. The underlying mechanisms of CVDs are extremely complicated and not fully revealed, leading to a challenge for CVDs treatment in modern medicine. Traditional Chinese medicine (TCM) characterized by multiple compounds and targets has shown its marked effects on CVDs therapy. However, system-level understanding of the molecular mechanisms is still ambiguous. In this study, a system pharmacology approach was developed to reveal the underlying molecular mechanisms of a clinically effective herb formula (Wen-Dan Decoction) in treating CVDs. 127 potential active compounds and their corresponding 283 direct targets were identified in Wen-Dan Decoction. The networks among active compounds, targets, and diseases were built to reveal the pharmacological mechanisms of Wen-Dan Decoction. A “CVDs pathway” consisted of several regulatory modules participating in therapeutic effects of Wen-Dan Decoction in CVDs. All the data demonstrates that Wen-Dan Decoction has multiscale beneficial activity in CVDs treatment, which provides a new way for uncovering the molecular mechanisms and new evidence for clinical application of Wen-Dan Decoction in cardiovascular disease.

Molecular understanding of the protective role of natural products on isoproterenol-induced myocardial infarction: A review

Modern medicine has been used to treat myocardial infarction, a subset of cardiovascular diseases, and have been relatively effective but not without adverse effects. Consequently, this issue has stimulated interest in the use of natural products, which may be equally effective and better tolerated. Many studies have investigated the cardioprotective effect of natural products, such as plant-derived phytochemicals, against isoproterenol (ISO)-induced myocardial damage; these have produced promising results on the basis of their antioxidant, anti-atherosclerotic, anti-apoptotic and anti-inflammatory activities. This review briefly introduces the pathophysiology of myocardial infarction (MI) and then addresses the progress of natural product research towards its treatment. We highlight the promising applications and mechanisms of action of plant extracts, phytochemicals and polyherbal formulations towards the treatment of ISO-induced myocardial damage. Most of the products displayed elevated antioxidant levels with decreased oxidative stress and lipid peroxidation, along with restoration of ionic balance and lowered expression of myocardial injury markers, pro-inflammatory cytokines, and apoptotic parameters. Likewise, lipid profiles were positively altered and histopathological improvements could be seen from, for example, the better membrane integrity, decreased necrosis, edema, infarct size, and leukocyte infiltration. This review highlights promising results towards the amelioration of ISO-induced myocardial damage, which suggest the direction for future research on natural products that could be used to treat MI.