Glycyrrhizin attenuates endotoxin- induced acute liver injury after partial hepatectomy in rats

Glabridin Ameliorates Alcohol-Caused Liver Damage by Reducing Oxidative Stress and Inflammation via p38 MAPK/Nrf2/NF-κB Pathway

Licorice is a traditional and versatile herbal medicine and food. Glabridin (Gla) is a kind of isoflavone extracted from the licorice root, which has anti-obesity, anti-atherosclerotic, and antioxidative effects. Alcoholic liver disease (ALD) is a widespread liver disease induced by chronic alcohol consumption. However, studies demonstrating the effect of Gla on ALD are rare. The research explored the positive effect of Gla in C57BL/6J mice fed by the Lieber-DeCarli ethanol mice diet and HepG2 cells treated with ethanol. Gla alleviated ethanol-induced liver injury, including reducing liver vacuolation and lipid accumulation. The serum levels of inflammatory cytokines were decreased in the Gla-treated mice. The reactive oxygen species and apoptosis levels were attenuated and antioxidant enzyme activity levels were restored in ethanol-induced mice by Gla treatment. In vitro, Gla reduced ethanol-induced cytotoxicity, nuclear factor kappa B (NF-κB) nuclear translocation, and enhanced nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nuclear translocation. Anisomycin (an agonist of p38 MAPK) eliminated the positive role of Gla on ethanol-caused oxidative stress and inflammation. On the whole, Gla can alleviate alcoholic liver damage via the p38 MAPK/Nrf2/NF-κB pathway and may be used as a novel health product or drug to potentially alleviate ALD.

Plants-based medicine implication in the evolution of chronic liver diseases

Hepatic disorders are considered major health problems, due to their high incidence, increased risk of chronicling or death and the costs involved in therapies. A large number of patients with chronic liver diseases use herbal medicines and dietary supplements in parallel with allopathic treatment. The current review provides a thorough analysis of the studies conducted on the most important species of medicinal plants used in this disease, bioactive compounds and on the activity of herbal medicines in the evolution of chronic liver diseases. However, a negative aspect is that there is frequently a lack of comprehensive data on the progression of the illness and the living standards of patients who are affected when evaluating the effects of these phytocomponents on the evolution of chronic liver disease, the patients' health, and their quality of life. It is essential to take this impairment into account when evaluating the long-term effects of herbal treatments on the health of individuals who suffer from liver illness. Bioactive phytocomponents may be a suitable source for the development of novel medications due to the correlation between traditional uses and medical advances. Additional high-quality preclinical examinations utilizing cutting-edge approaches are needed to assess safety and effectiveness and to detect, categorize, and standardize the active substances and their formulations for the most suitable therapeutic management of liver illnesses.

The Combined Effect of Licorice Extract and Bone Marrow Mesenchymal Stem Cells on Cisplatin-Induced Hepatocellular Damage in Rats

Drug-induced liver damage is a life-threatening disorder, and one major form of it is the hepatotoxicity induced by the drug cisplatin. In folk medicine, Licorice (Glycyrrhiza glabra (is used for detoxification and is believed to be a potent antioxidant. Currently, the magically self-renewable potential of bone marrow mesenchymal stem cells (BM-MSCs) has prompted us to explore their hepatoregenerative capability. The impact of G. glabra extract (GGE) and BM-MSCs alone and, in combination, on protecting against hepatotoxicity was tested on cisplatin-induced liver injury in rats. Hepatic damage, as revealed by liver histopathology and increased levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and malondialdehyde (MDA), was elevated in rats by received 7 mg/kg of cisplatin intraperitoneally. The combination of GGE and BM-MSCs returned the enzyme levels to near the normal range. It also improved levels of liver superoxide dismutase (SOD) and glutathione (GSH) and reduced MDA levels. Additionally, it was found that when GGE and BM-MSCs were used together, they significantly downregulated caspase9 (Casp9), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), and interleukin-1β (IL-1β), which are involved in severe proinflammatory and apoptotic signaling cascades in the liver. Moreover, combining GGE and BM-MSCs led to the normal result of hepatocytes in several examined liver histological sections. Therefore, our findings suggest that GGE may have protective effects against oxidative liver damage and the promising regenerative potential of BM-MSCs.

Synthesis, Antiviral, and Antibacterial Activity of the Glycyrrhizic Acid and Glycyrrhetinic Acid Derivatives

Glycyrrhizic acid and its primary metabolite glycyrrhetinic acid, are the main active ingredients in the licorice roots (glycyrrhiza species), which are widely used in several countries of the world, especially in east asian countries (China, Japan). These ingredients and their derivatives play an important role in treating many diseases, especially infectious diseases such as COVID-19 and hepatic infections. This review aims to summarize the different ways of synthesising the amide derivatives of glycyrrhizic acid and the main ways to synthesize the glycyrrhitinic acid derivatives. Also, to determine the main biological and pharmacological activity for these compounds from the previous studies to provide essential data to researchers for future studies.

Supplementary Information

The online version contains supplementary material available at 10.1134/S1068162022050132.

The hepatoprotective effects of plant-based foods based on the "gut-liver axis": a prospective review

The importance of the "gut-liver axis" in the pathogenesis of liver diseases has been revealed recently; which promotes the process of developing preventive and therapeutic strategies. However, considering that there are still many challenges in the medical treatment of liver diseases, potential preventive dietary intervention may be a good alternative choice. Plant-based foods have received much attention due to their reported health-promoting effects in targeting multiple pathways involved in the pathogenesis of liver diseases as well as the relative safety for general use. Based on the PubMed and Web of Science databases, this review emphatically summarizes the plant-based foods and their chemical constituents with reported effects to impact the LPS/TLR4 signaling pathway of gut-liver axis of various liver diseases, reflecting their health benefits in preventing/alleviating liver diseases. Moreover, some plant-based foods with potential gut-liver effects are specifically analyzed from the reported studies and conclusions. This review intends to provide readers an overview of the current progress in the field of this research topic. We expect to see more hepatoprotective measures for alleviating the current prevalence of liver diseases.

Glycyrrhiza glabra (Licorice): A Comprehensive Review on Its Phytochemistry, Biological Activities, Clinical Evidence and Toxicology

There are more than 30 species of Glycyrrhiza genus extensively spread worldwide. It was the most prescribed herb in Ancient Egyptian, Roman, Greek, East China, and the West from the Former Han era. There are various beneficial effects of licorice root extracts, such as treating throat infections, tuberculosis, respiratory, liver diseases, antibacterial, anti-inflammatory, and immunodeficiency. On the other hand, traditional medicines are getting the attraction to treat many diseases. Therefore, it is vital to screen the medicinal plants to find the potential of new compounds to treat chronic diseases such as respiratory, cardiovascular, anticancer, hepatoprotective, etc. This work comprehensively reviews ethnopharmacological uses, phytochemistry, biological activities, clinical evidence, and the toxicology of licorice, which will serve as a resource for future clinical and fundamental studies. An attempt has been made to establish the pharmacological effect of licorice in different diseases. In addition, the focus of this review article is on the molecular mechanism of licorice extracts and their four flavonoids (isoliquiritigenin, liquiritigenin, lichalocone, and glabridin) pharmacologic activities. Licorice could be a natural alternative for current therapy to exterminate new emerging disorders with mild side effects. This review will provide systematic insights into this ancient drug for further development and clinical use.

Advances in adjunct therapy against tuberculosis: Deciphering the emerging role of phytochemicals

Eastern countries are a major source of medicinal plants, which set up a rich source of ethnopharmacologically known medicines used in the treatment of various diseases. These traditional medicines have been known as complementary, alternative, or nonconventional therapy across globe for ages. Tuberculosis (TB) poses a huge global burden and leads to maximum number of deaths due to an infectious agent. Treatment of TB using Directly Observed Treatment Short-course (DOTS) therapy comprises multiple antibiotics is quite lengthy and causes serious side-effects in different organs. The length of the TB treatment leads to withdrawal from the patients, which paves the way for the emergence of drug resistance in the bacterial population. These concerns related to therapy need serious and immediate interventions. Traditional medicines using phytochemicals has shown to provide tremendous potential in TB treatment, mainly in the eradication of Mycobacterium tuberculosis (M.tb), increasing natural immunity, and managing the side effects of anti-TB drugs. This review describes the antituberculosis potential of selected ethnopharmacologically important phytochemicals as potential immune-modulator and as an adjunct-therapy in TB. This review will be a useful reference for researchers working on ethnopharmacology and will open the door for the discovery of novel agents as an adjunct-therapy to tuberculosis.

Effect of glycyrrhizic acid and 18β-glycyrrhetinic acid on the differentiation of human umbilical cord-mesenchymal stem cells into hepatocytes

BACKGROUND

End-stage liver disease is a global health complication with high prevalence and limited treatment options. Cell-based therapies using mesenchymal stem cells (MSCs) emerged as an alternative approach to support hepatic regeneration. In vitro preconditioning strategies have been employed to strengthen the regenerative and differentiation potential of MSCs towards hepatic lineage. Chemical compounds of the triterpene class; glycyrrhizic acid (GA) and 18β-glycyrrhetinic acid (GT) possess diverse therapeutic properties including hepato-protection and anti-fibrosis characteristics. They are capable of modulating several signaling pathways that are crucial in hepatic regeneration. Preconditioning with hepato-protective triterpenes may stimulate MSC fate transition towards hepatocytes.

AIM

To explore the effect of GA and GT on hepatic differentiation of human umbilical cord-MSCs (hUC-MSCs).

METHODS

hUC-MSCs were isolated and characterized phenotypically by flow cytometry and immunocytochemistry for the expression of MSC-associated surface molecules. Isolated cells were treated with GA, GT, and their combination for 24 h and then analyzed at three time points; day 7, 14, and 21. qRT-PCR was performed for the expression of hepatic genes. Expression of hepatic proteins was analyzed by immunocytochemistry at day 21. Periodic acid Schiff staining was performed to determine the functional ability of treated cells.

RESULTS

The fusiform-shaped morphology of MSCs in the treatment groups in comparison with the untreated control, eventually progressed towards the polygonal morphology of hepatocytes with the passage of time. The temporal transcriptional profile of preconditioned MSCs displayed significant expression of hepatic genes with increasing time of differentiation. Preconditioned cells showed positive expression of hepatocyte-specific proteins. The results were further corroborated by positive periodic acid Schiff staining, indicating the presence of glycogen in their cytoplasm. Moreover, bi-nucleated cells, which is the typical feature of hepatocytes, were also seen in the preconditioned cells.

CONCLUSION

Preconditioning with glycyrrhizic acid, 18β-glycyrrhetinic acid and their combination, successfully differentiates hUC-MSCs into hepatic-like cells. These MSCs may serve as a better therapeutic option for degenerative liver diseases in future.

Advances in Pharmacological Activities and Mechanisms of Glycyrrhizic Acid

Licorice (Glycyrrhiza glabra L.) is widely regarded as an important medicinal plant and has been used for centuries in traditional medicine because of its therapeutic properties. Studies have shown that metabolites isolated from licorice have many pharmacological activities, such as antiinflammatory, anti-viral, participation in immune regulation, anti-tumor and other activities. This article gives an overview of the pharmacological activities and mechanisms of licorice metabolites and the adverse reactions that need attention. This review helps to further investigate the possibility of licorice as a potential drug for various diseases. It is hoped that this review can provide a relevant theoretical basis for relevant scholars' research and their own learning.

Glycyrrhizic Acid Modulates Apoptosis through Extrinsic/Intrinsic Pathways and Inhibits Protein Kinase B- and Extracellular Signal-Regulated Kinase-Mediated Metastatic Potential in Hepatocellular Carcinoma In Vitro and In Vivo

A previous study presented that glycyrrhizic acid as the hepatoprotective agent inhibits total parenteral nutrition-associated acute liver injury in rats. However, the anticancer effect and mechanism of glycyrrhizic acid in human hepatocellular carcinoma (HCC) is ambiguous. The purpose of the present study was to investigate the effect of glycyrrhizic acid on apoptosis dysregulation and metastatic potential in HCC in vitro and in vivo. Both SK-Hep1 and Hep3B cells were treated with different concentrations of glycyrrhizic acid for 24 or 48h. SK-Hep1/luc2 tumor-bearing mice were treated with vehicle or glycyrrhizic acid (50mg/kg/day by intraperitoneal injection) for 7 days. Tumor cells growth, apoptotic, and metastatic signaling transduction were evaluated by using MTT assay, digital caliper, bioluminescence imaging (BLI), flow cytometry, western blotting assay, and immunohistochemistry (IHC) staining. The results demonstrated glycyrrhizic acid significantly inhibits tumor cell growth, cell invasion, and expression of AKT (Ser473), extracellular-signal-regulated kinase (ERK), epidermal growth factor receptor (EGFR) phosphorylation, anti-apoptotic and metastatic proteins in HCC in vitro and in vivo. Glycyrrhizic acid also significantly triggered apoptosis and extrinsic/intrinsic apoptotic signaling transduction. In addition, PD98059 (ERK inhibitor) and LY294002 (AKT inhibitor) obviously reduced cell invasion and expression of metastasis-associated proteins. Taken together, these results indicated that glycyrrhizic acid induces apoptosis through extrinsic/intrinsic apoptotic signaling pathways and diminishes EGFR/AKT/ERK-modulated metastatic potential in HCC in vitro and in vivo.

An Integrated Approach Exploring the Synergistic Mechanism of Herbal Pairs in a Botanical Dietary Supplement: A Case Study of a Liver Protection Health Food

Herbal pairs are used as a bridge between single herb and polyherbal formulas in Traditional Chinese Medicine (TCM) to provide rationale for complicated TCM formulas. The effectiveness and rationality of TCM herbal pairs have been widely applied as a strategy for dietary supplements. However, due to the complexity of the phytochemistry of individual and combinations of herbal materials, it is difficult to reveal their effective and synergistic mechanisms from a molecular or systematic point of view. In order to address this question, UPLC-Q-TOF/MS analysis and System Pharmacology tools were applied to explore the mechanism of action, using a White Peony (Paeoniae Radix Alba) and Licorice (Glycyrrhizae Radix et Rhizoma)-based dietary supplement. A total of sixteen chemical constituents of White Peony and Licorice were isolated and identified, which interact with 73 liver protection-related targets. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were then performed along with network analysis. Results showed that the synergistic mechanism of the White Peony and Licorice herbal pair was associated with their coregulation of bile secretion and ABC transporter pathways. In addition, Licorice exhibits a specific response to drug and xenobiotic metabolism pathways, whereas White Peony responds to Toll-like receptor signaling, C-type lectin receptor signaling, IL-17 signaling, and TNF signaling pathways, resulting in the prevention of hepatocyte apoptosis and the reduction of immune and inflammation-mediated liver damage. These findings suggest that a White Peony and Licorice herbal pair supplement would have a liver-protecting benefit through complimentary and synergistic mechanisms. This approach provides a new path to explore herbal compatibility in dietary supplements derived from TCM theory.

The concurrent exposure to aluminium and fructose induces liver injury in rats: Protection by monoammonium glycyrrhizinate

Aluminium is a ubiquitous element that occurs naturally in the soil making human exposure to it unavoidable. It is implicated in the aetiology of different neurodegenerative diseases and can induce liver injury. In addition, insulin resistance (IR) plays an essential role in the pathogenesis and the progression of liver disorders. The increased consumption of fructose contained in soft drinks and western pattern diet results in IR that along with the wide distribution of aluminium make the concurrent exposure conceivable and increase the risk of liver injury. Therefore, the present study explores the hepatotoxic effects of aluminium and fructose administered concurrently and evaluates the possible protection by monoammonium glycyrrhizinate (MAG). Liver injury was induced by the administration of aluminium chloride (34 mg/kg/d) plus 10% (w/v) fructose in drinking water. Male rats were treated with either MAG (40 mg/kg/d) or silymarin (SIL, 100 mg/kg/d). The concurrent administration of aluminium and fructose (FRUAL) induced liver injury manifested as a significant elevation of serum liver enzymes activities, bilirubin level, and prothrombin time, as well as reduction of albumin level. On the other hand, the administration of MAG improved the FRUAL-induced aberrations of liver function tests and hepatic cytoarchitecture. We assume that the MAG-induced suppression of oxidative stress, toll-like receptor 4 pathway activation, inflammation, and apoptosis might play a crucial role in the hepatoprotective effect of MAG in this model. Intriguingly, the hepatoprotective effect MAG against FRUAL-induced liver injury surpasses that of the gold standard SIL, suggesting MAG as a better alternative to SIL.

Natural products in licorice for the therapy of liver diseases: Progress and future opportunities

Liver diseases related complications represent a significant source of morbidity and mortality worldwide, creating a substantial economic burden. Oxidative stress, excessive inflammation, and dysregulated energy metabolism significantly contributed to liver diseases. Therefore, discovery of novel therapeutic drugs for the treatment of liver diseases are urgently required. Licorice is one of the most commonly used herbal drugs in Traditional Chinese Medicine for the treatment of liver diseases and drug-induced liver injury (DILI). Various bioactive components have been isolated and identified from the licorice, including glycyrrhizin, glycyrrhetinic acid, liquiritigenin, Isoliquiritigenin, licochalcone A, and glycycoumarin. Emerging evidence suggested that these natural products relieved liver diseases and prevented DILI through multi-targeting therapeutic mechanisms, including anti-steatosis, anti-oxidative stress, anti-inflammation, immunoregulation, anti-fibrosis, anti-cancer, and drug-drug interactions. In the current review, we summarized the recent progress in the research of hepatoprotective and toxic effects of different licorice-derived bioactive ingredients and also highlighted the potency of these compounds as promising therapeutic options for the treatment of liver diseases and DILI. We also outlined the networks of underlying molecular signaling pathways. Further pharmacology and toxicology research will contribute to the development of natural products in licorice and their derivatives as medicines with alluring prospect in the clinical application.

The Protective Effects of Glycyrrhetinic Acid and Chrysin against Ischemia-Reperfusion Injury in Rat Ovaries

Objective

To evaluate the protective effects of glycyrrhetinic acid (GA) and chrysin (CH) on experimental ischemia-reperfusion (I/R) injury in rat ovaries using tissue oxidative stress marker levels, hormone levels, and histopathological scores.

Methods

Sixty healthy rats were randomly divided into six equal groups: control, I/R, I/R + CH (50 mg/kg/day), I/R + GA (100 mg/kg/day), CH (50 mg/kg/day), and GA (100 mg/kg/day). Biochemical, hormonal, and histopathological evaluations were performed on blood and tissue samples 14 days after CH and GA treatment.

Results

The antioxidant defense system parameters were significantly higher in the ovarian tissues of the I/R + CH and I/R + GA groups than in those of the I/R group. Serum follicle-stimulating hormone levels were significantly reduced, and serum anti-Müllerian hormone levels were significantly increased in rats treated with CH and GA compared with those in the I/R group. Additionally, the histopathological scores of the I/R + CH and I/R + GA groups were significantly improved compared with those of the I/R group.

Conclusions

The significant improvements in tissue oxidative stress parameters, serum hormone levels, and histological scores observed in this study indicate that treatment with CH or GA may be a conservative approach to prevent I/R injury in adnexal torsion cases after the ovarian detorsion procedure.

Anti-inflammatory and hepatoprotective effects of glycyrrhetinic acid on CCl4-induced damage in precision-cut liver slices from Jian carp (Cyprinus carpio var. jian) through inhibition of the nf-kƁ pathway

In order to evaluate the antioxidant and anti-inflammatory effects of glycyrrhetinic acid (GA) on carbon tetrachloride (CCl₄)-induced damage in precision-cut liver slices (PCLS) from Jian carp (Cyprinus carpio. Jian), an acute liver damage model was established in this study. The viability of PCLS, levels of anti-oxidases in liver homogenates, expression of inflammation-related genes including nuclear factor-κB (nf-κB)/c-rel, inducible nitric oxide synthase (inos), interleukin-1β (il-1β), interleukin-6 (il-6) and interleukin-8 (il-8), and protein levels of (nf-κB)/c-rel in liver tissues were measured. The results showed that pretreatment of PCLS with GA at 5 and 10 μg/mL for 6 h significantly inhibited the cytotoxicity of CCl₄. GA attenuated CCl₄-induced oxidative stress in PCLS through promoting the recovery of superoxide dismutase (SOD) and glutathione (GSH) levels, and inhibiting malondialdehyde (MDA) synthesis. In inflammatory response, GA at both 5 and 10 μg/mL significantly inhibited the increase in mRNA levels of inflammatory cytokines including nf-kƁ/c-rel, inos, il-1β, il-6 and il-8, and the protein level of Nf-kƁ/C-rel induced by CCl₄. Furthermore, treatment with pyrrolyl dithiocarbamate (PDTC, 4 μg/mL), an inhibitor of nuclear transcription factor nf-kB, significantly inhibited nf-kB levels, and transcription of downstream cytokines inos, il-1β, il-6 and il-8, also the viability of PCLS was significantly increased. These results indicated that GA suppressed inflammation and reduced cytotoxicity by inhibiting the nf-kƁ signaling pathway, and plays a role in liver protection.

Effects of diammonium glycyrrhizinate on random skin flap survival in rats: An experimental study

Partial necrosis of skin flaps continues to restrict the survival of local skin flaps following plastic and reconstructive surgeries. The aim of the present study was to investigate the effects of diammonium glycyrrhizinate (DG), a salt of glycyrrhetinic acid that has been widely used in the therapy of chronic hepatitis and human immunodeficiency virus infection, on random skin flap survival in rats. McFarlane flaps were established in 60 male Sprague-Dawley rats randomly divided into three groups. Group I served as the control group and was injected with saline (10 mg/kg) once per day. Group II and group III were the experimental groups, and were injected with 10 mg/kg DG once and twice per day, respectively. On day 7, the survival area of the flap was measured. Tissue samples were stained with hematoxylin and eosin and immunohistochemically evaluated. Tissue edema, neutrophil density, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were evaluated. The mean survival areas of the flaps of group II were significantly larger when compared with those of group I (P<0.05), and the rats of group III exhibited significantly higher survival areas than group II (P<0.05). Histologic and immunohistochemical evaluation showed that microvessel development and the expression level of vascular endothelial growth factor were higher in the two experimental groups than in the control group. Furthermore, SOD activity was significantly increased (P<0.05), while the neutrophil density and MDA level were significantly reduced (P<0.05) in group II when compared with group I. Significant differences between group II and group III with regard to SOD activity and MDA level were also observed (P<0.05). Thus, DG may have a dose-dependent effect on promoting the survival of random skin flaps.

Akt: A Therapeutic Target in Hepatic Ischemia-Reperfusion Injury

BACKGROUND

Liver transplantation is the second most common transplant procedure in the United States. A leading cause of post-transplantation organ dysfunction is I/R injury. During I/R injury, the serine/threonine kinase Akt is activated, stimulating downstream mediators to promote cellular survival. Due to the cellular effects of Akt, therapeutic manipulation of the Akt pathway can help reduce cellular damage during hepatic I/R that occurs during liver transplantation.

OBJECTIVE

A full description of therapeutic options available that target Akt to reduce hepatic I/R injury has not been addressed within the literature. The purpose of this review is to illuminate advances in the manipulation of Akt that can be used to therapeutically target I/R injury in the liver.

METHODS

An in depth literature review was performed using the Scopus and PubMed databases. A total of 75 published articles were utilized for this manuscript. Terminology searched includes a combination of "hepatic ischemia/reperfusion injury", "Akt/PKB", "preconditioning" and "postconditioning."

RESULTS

Four principal methods that reduce I/R injury include hepatic pre- and postconditioning, pharmacological intervention and future miRNA/gene therapy. Discussed therapies used serum alanine aminotransferase levels, liver histology and phosphorylation of downstream mediators to confirm the Akt protective effect.

CONCLUSION

The activation of Akt from the reviewed therapies has resulted in predictable reduction in hepatocyte damage using the previously mentioned measurements. In a clinical setting, these therapies could potentially be used in combination to achieve better outcomes in hepatic transplant patients. Evidence supporting reduced I/R injury through Akt activation warrants further studies in human clinical trials.

IRE1-RACK1 axis orchestrates ER stress preconditioning-elicited cytoprotection from ischemia/reperfusion injury in liver

Endoplasmic reticulum (ER) stress is involved in ischemic preconditioning that protects various organs from ischemia/reperfusion (I/R) injury. We established an in vivo ER stress preconditioning model in which tunicamycin was injected into rats before hepatic I/R. The hepatic I/R injury, demonstrated by serum aminotransferase level and the ultra-structure of the liver, was alleviated by administration of tunicamycin, which induced ER stress in rat liver by activating inositol-requiring enzyme 1 (IRE1) and upregulating 78 kDa glucose-regulated protein (GRP78). The proteomic identification for IRE1 binders revealed interaction and cooperation among receptor for activated C kinase 1 (RACK1), phosphorylated AMPK, and IRE1 under ER stress conditions in a spatiotemporal manner. Furthermore, in vitro ER stress preconditioning was induced by thapsigargin and tunicamycin in L02 and HepG2 cells. Surprisingly, BCL2 was found to be phosphorylated by IRE1 under ER stress conditions to prevent apoptotic process by activation of autophagy. In conclusion, ER stress preconditioning protects against hepatic I/R injury, which is orchestrated by IRE1-RACK1 axis through the activation of BCL2. Our findings provide novel insights into the molecular pathways underlying ER stress preconditioning-elicited cytoprotective effect against hepatic I/R injury.

Liver fibrosis and protection mechanisms action of medicinal plants targeting apoptosis of hepatocytes and hepatic stellate cells

Following chronic liver injury, hepatocytes undergo apoptosis leading to activation of hepatic stellate cells (HSC). Consequently, activated HSC proliferate and produce excessive extracellular matrix, responsible for the scar formation. The pandemic trend of obesity, combined with the high incidence of alcohol intake and viral hepatitis infections, highlights the urgent need to find accessible antifibrotic therapies. Treatment strategies should take into account the versatility of its pathogenesis and act on all the cell lines involved to reduce liver fibrosis. Medicinal plants are achieving popularity as antifibrotic agents, supported by their safety, cost-effectiveness, and versatility. This review will describe the role of hepatocytes and HSC in the pathogenesis of liver fibrosis and detail the mechanisms of modulation of apoptosis of both cell lines by twelve known hepatoprotective plants in order to reduce liver fibrosis.

Carvacrol alleviates ischemia reperfusion injury by regulating the PI3K-Akt pathway in rats

Background

Liver ischemia reperfusion (I/R) injury is a common pathophysiological process in many clinical settings. Carvacrol, a food additive commonly used in essential oils, has displayed antimicrobials, antitumor and antidepressant-like activities. In the present study, we investigated the protective effects of carvacrol on I/R injury in the Wistar rat livers and an in vitro hypoxia/restoration (H/R) model.

Methods

The hepatoportal vein, hepatic arterial and hepatic duct of Wistar rats were isolated and clamped for 30 min, followed by a 2 h reperfusion. Buffalo rat liver (BRL) cells were incubated under hypoxia for 4 h, followed normoxic conditions for 10 h to establish the H/R model in vitro. Liver injury was evaluated by measuring serum levels of alanine aminotransferase (ALT) and aspatate aminotransferase (AST), and hepatic levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondiadehyde (MDA), and hepatic histology and TUNEL staining. MTT assay, flow cytometric analysis and Hoechst 33258 staining were used to evaluate the proliferation and apoptosis of BRL cells in vitro. Protein expression was examined by Western Blot analysis.

Results

Carvacrol protected against I/R-induced liver damage, evidenced by significantly reducing the serum levels of ALT and AST, histological alterations and apoptosis of liver cells in I/R rats. Carvacrol exhibited anti-oxidative activity in the I/R rats, reflected by significantly reducing the activity of SOD and the content of MDA, and restoring the activity of CAT and the content of GSH, in I/R rats. In the in vitro assays, carvacrol restored the viability and inhibited the apoptosis of BRL cells, which were subjected to a mimic I/R injury induced by hypoxia. In the investigation on molecular mechanisms, carvacrol downregulated the expression of Bax and upregulated the expression of Bcl-2, thus inhibited the activation of caspase-3. Carvacrol was also shown to enhance the phosphorylation of Akt.

Conclusion

The results suggest that carvacrol could alleviate I/R-induced liver injury by its anti-oxidative and anti-apoptotic activities, and warrant a further investigation for using carvacrol to protect I/R injury in clinic.

Induced hypothermia reduces the hepatic inflammatory response in a swine multiple trauma model

BACKGROUND

Mild therapeutic hypothermia following trauma has been introduced in several studies to reduce the posttraumatic inflammation and organ injury. In this study, we analyzed the effects of induced mild hypothermia (34°C) on the inflammation of the shock organs liver and kidney.

METHODS

In a porcine model of multiple trauma including blunt chest trauma, liver laceration, and hemorrhagic shock followed by fluid resuscitation, the influence of induced hypothermia on hepatic and renal damage and organ-specific inflammation were evaluated. A total of 40 pigs were randomly assigned to four groups, which were sham (anesthesia only) or trauma groups receiving either hypothermia or normothermia. The parameters analyzed were laboratory parameters (aspartate transaminase [AST], lactate dehydrogenase, urea, creatinine) as well as hepatic and renal cytokine expression determined by real-time polymerase chain reaction (interleukin 6 [IL-6], IL-8). Blinded analysis of histologic changes in the liver and kidney was performed.

RESULTS

Fifteen and a half hours following combined trauma, hepatic cytokine expression and liver damage were significantly increased in animals with normothermia compared with the respective sham group. Hypothermia, however, resulted in a fivefold reduced hepatic expression of IL-8 (mean ± SE, 2.4 ± 1.3; p = 0.01) when compared with the normothermic trauma group (IL-8, 12.8 ± 4.7). Accordingly, granulocyte infiltration and a histologic, semiquantitative score for liver injury were significantly higher in the normothermic trauma group. Serum AST levels raised significantly after trauma and normothermia compared with the respective sham group, while AST levels showed no difference from the sham groups in the hypothermic trauma group. In contrast, neither trauma nor hypothermia influenced the expression of IL-6 and IL-8 and tissue injury in the kidney.

CONCLUSION

Therapeutic hypothermia seems to attenuate the hepatic inflammatory response and the associated liver injury after severe trauma. Therefore, induced hypothermia might represent a potential therapeutic strategy to avoid posttraumatic organ dysfunction.

Glycyrrhizic acid in the treatment of liver diseases: literature review

Glycyrrhizic acid (GA) is a triterpene glycoside found in the roots of licorice plants (Glycyrrhiza glabra). GA is the most important active ingredient in the licorice root, and possesses a wide range of pharmacological and biological activities. GA coupled with glycyrrhetinic acid and 18-beta-glycyrrhetic acid was developed in China or Japan as an anti-inflammatory, antiviral, and antiallergic drug for liver disease. This review summarizes the current biological activities of GA and its medical applications in liver diseases. The pharmacological actions of GA include inhibition of hepatic apoptosis and necrosis; anti-inflammatory and immune regulatory actions; antiviral effects; and antitumor effects. This paper will be a useful reference for physicians and biologists researching GA and will open the door to novel agents in drug discovery and development from Chinese herbs. With additional research, GA may be more widely used in the treatment of liver diseases or other conditions.

Candesartan and glycyrrhizin ameliorate ischemic brain damage through downregulation of the TLR signaling cascade

Stroke is the second leading cause of death in industrialized countries and the most frequent cause of permanent disability in adults worldwide. The final outcome of stroke is determined not only by the volume of the ischemic core, but also by the extent of secondary brain damage inflicted to penumbral tissues by brain swelling, impaired microcirculation, and inflammation. The only drug approved for the treatment ischemic stroke is recombinant tissue plasminogen activator (rt-PA). The current study was designed to investigate the protective effects of candesartan (0.15 mg/kg, orally) and glycyrrhizin (30 mg/kg, orally) experimentally-induced ischemic brain damage in C57BL/6 mice (middle cerebral artery occlusion, MCAO) in comparison to the effects of a standard neuroprotective drug (cerebrolysin, 7.5 mg/kg, IP). All drugs were administered 30 min before and 24h after MCAO. Both candesartan and glycyrrhizin ameliorated the deleterious effects of MCAO as indicated by the improvement in the performance of the animals in behaviour tests, reduction in brain infarction, neuronal degeneration, and leukocyte infiltration. In addition, MCAO induced a significant upregulation in the different elements of the TLR pathway including TLR-2 and TLR-4, Myd88, TRIF and IRF-3 and the downstream effectors TNF-α, IL-1β, IL-6 and NF-kB. All these changes were significantly ameliorated by treatment with candesartan and glycyrrhizin. The results of the current study represent a new indication for both candesartan and glycyrrhizin in the management of ischemic stroke with effects comparable to those of the standard neuroprotective drug cerebrolysin.

Correlation analysis between the rate of respiration in the root and the active components in licorice (Glycyrrhiza uralensis)

The aim of this study was to investigate the correlation between root respiration and the percentage of active components in licorice (Glycyrrhiza uralensis Fisch.), in order to provide a foundation for the regulation and modulation of the quality of G. uralensis. Respiration efflux of annual and biennial G. uralensis was determined using a Li-7000 CO₂/H₂O analyzer. The root systems were scanned at a resolution of 3,000 dpi using an Epson Expression 10000XL scanner. Root growth was determined by analyzing the scanned images using WinRHIZO version Pro2007d software and the rate of respiration in the root was subsequently calculated. In addition, the percentages of the five major active components in licorice, glycyrrhizic acid, glycyrrhizin, isoliquiritin, liquiritigenin and isoliquiritigenin, were detected using high-performance liquid chromatography (HPLC). The correlation between the root respiration and the percentage of the active components was investigated. Significant seasonal changes were observed in the rates of respiration of first and zero-class roots. In annual and biennial G. uralensis, the maximum and minimum values for rate of respiration were present in July (P<0.05) and November (P<0.05), respectively. The correlation coefficients between the five major active components and the rate of respiration were −0.304 (glycyrrhizin), −0.129 (liquiritigenin), −0.441 (glycyrrhizic acid; P<0.05), −0.471 (isoliquiritin; P<0.05) and 0.148 (isoliquiritigenin). The percentages of glycyrrhizic acid and isoliquiritin were significantly negatively correlated with the rate of respiration in annual and biennial G. uralensis. Understanding the correlation between the root rate of respiration and the active components in G. uralensis may be beneficial to ensuring the quality of cultivated G. uralensis.

Carbenoxolone blocks endotoxin-induced protein kinase R (PKR) activation and high mobility group box 1 (HMGB1) release

The pathogen- and damage-associated molecular patterns (for example, bacterial endotoxin and adenosine 5'-triphosphate [ATP]) activate the double-stranded RNA-activated protein kinase R (PKR) to trigger the inflammasome-dependent high mobility group box 1 (HMGB1) release. Extracellular ATP contributes to the inflammasome activation through binding to the plasma membrane purinergic P2X7 receptor (P2X7R), triggering the opening of P2X7R channels and the pannexin-1 (panx-1) hemichannels permeable for larger molecules up to 900 daltons. It was previously unknown whether panx-1 channel blockers can abrogate lipopolysaccharide (LPS)-induced PKR activation and HMGB1 release in innate immune cells. Here we demonstrated that a major gancao (licorice) component (glycyrrhizin, or glycyrrhizic acid) derivative, carbenoxolone (CBX), dose dependently abrogated LPS-induced HMGB1 release in macrophage cultures with an estimated IC50 ≈ 5 μmol/L. In an animal model of polymicrobial sepsis (induced by cecal ligation and puncture [CLP]), repetitive CBX administration beginning 24 h after CLP led to a significant reduction of circulating and peritoneal HMGB1 levels, and promoted a significant increase in animal survival rates. As did P2X7R antagonists (for example, oxidized ATP, oATP), CBX also effectively attenuated LPS-induced P2X7R/panx-1 channel activation (as judged by Lucifer Yellow dye uptake) and PKR phosphorylation in primary peritoneal macrophages. Collectively, these results suggested that CBX blocks LPS-induced HMGB1 release possibly through impairing PKR activation, supporting the involvement of PKR in the regulation of HMGB1 release.

Glycyrrhizic acid attenuates CCl4-induced hepatocyte apoptosis in rats via a p53-mediated pathway

AIM: To investigate the effect of glycyrrhizic acid (GA) on carbon tetrachloride (CCl₄)-induced hepatocyte apoptosis in rats via a p53-dependent mitochondrial pathway.

METHODS: Forty-five male Sprague-Dawley rats were randomly and equally divided into three groups, the control group, the CCl₄ group, and the GA treatment group. To induce liver fibrosis in this model, rats were given a subcutaneous injection of a 40% solution of CCl₄ in olive oil at a dose of 0.3 mL/100 g body weight biweekly for 8 wk, while controls received the same isovolumetric dose of olive oil by hypodermic injection, with an initial double-dose injection. In the GA group, rats were also treated with a 40% solution of CCl₄ plus 0.2% GA solution in double distilled water by the intraperitoneal injection of 3 mL per rat three times a week from the first week following previously published methods, with modifications. Controls were given the same isovolumetric dose of double distilled water. Liver function parameters, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. Pathologic changes in the liver were detected by hematoxylin and eosin staining. Collagen fibers were evaluated by Sirius red staining. Hepatocyte apoptosis was investigated using the terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick end labeling (TUNEL) assay and the cleaved caspase-3 immunohistochemistry assay. The expression levels of p53 and apoptosis-related proteins were evaluated by immunohistochemistry or Western blotting analysis.

RESULTS: After 8 wk of treatment, GA significantly reduced serum activity of ALT (from 526.7 ± 57.2 to 342 ± 44.8, P < 0.05) and AST (from 640 ± 33.7 to 462.8 ± 30.6, P < 0.05), attenuated the changes in liver histopathology and reduced the staging score (from 3.53 ± 0.74 to 3.00 ± 0.76, P < 0.05) in CCl₄-treated rats. GA markedly reduced the positive area of Sirius red and the ratio of the hepatic fibrotic region (from 7.87% ± 0.66% to 3.68% ± 0.32%, P < 0.05) compared with the CCl₄ group. GA also decreased the expression level of cleaved caspase-3 compared to the CCl₄ group. TUNEL assay indicated that GA significantly diminished the number of TUNEL-positive cells compared with the CCl₄ group (P < 0.05). GA treatment clearly decreased the level of p53 (P < 0.05) detected by immunohistochemistry and Western blotting analysis. Compared with the CCl₄ group, we also found that GA reduced the Bax/Bcl-2 ratio (P < 0.05), the expression of cleaved caspase-3 (P < 0.05), cleaved caspase-9 (P < 0.05), and inhibited cytochrome C and second mitochondria-derived activator of caspases (Smac) release from mitochondria to cytoplasm, i.e., GA reduced the expression level of Smac, which inhibited c-IAP1 activity (P < 0.05), ultimately inhibiting the activity of caspase-3, according to Western blotting analysis. As a result, GA suppressed activation of the caspase cascades and prevented hepatocyte apoptosis.

CONCLUSION: GA can inhibit CCl₄-induced hepatocyte apoptosis via a p53-dependent mitochondrial pathway to retard the progress of liver fibrosis in rats.

Recent advances in natural products from plants for treatment of liver diseases

Liver disease is any condition that may cause liver inflammation or tissue damage and affects liver function. Natural products that are found in vegetables, fruits, plant extracts, herbs, insects, and animals, have been traditionally used for treating liver diseases. They are chemical compounds that usually have biological activities for use in drug discovery and design. Many natural products have been clinically available as potent hepatoprotective agents against commonly occurring liver diseases. This review summarizes the current progress in the basic, clinical, and translational research on natural products in treatment of various liver diseases. Furthermore, we will focus on the discovery and biological evaluation of the natural products, which shows potential as a new therapeutic agent of liver diseases.

Herbal products: benefits, limits, and applications in chronic liver disease

Complementary and alternative medicine soughts and encompasses a wide range of approaches; its use begun in ancient China at the time of Xia dynasty and in India during the Vedic period, but thanks to its long-lasting curative effect, easy availability, natural way of healing, and poor side-effects it is gaining importance throughout the world in clinical practice. We conducted a review describing the effects and the limits of using herbal products in chronic liver disease, focusing our attention on those most known, such as quercetin or curcumin. We tried to describe their pharmacokinetics, biological properties, and their beneficial effects (as antioxidant role) in metabolic, alcoholic, and viral hepatitis (considering that oxidative stress is the common pathway of chronic liver diseases of different etiology). The main limit of applicability of CAM comes from the lacking of randomized, placebo-controlled clinical trials giving a real proof of efficacy of those products, so that anecdotal success and personal experience are frequently the driving force for acceptance of CAM in the population.

Glycyrrhizin attenuates HMGB1-induced hepatocyte apoptosis by inhibiting the p38-dependent mitochondrial pathway

AIM: To examine how high-mobility group box 1 (HMGB1) regulates hepatocyte apoptosis and, furthermore, to determine whether glycyrrhizin (GL), a known HMGB1 inhibitor, prevents HMGB1-induced hepatocyte apoptosis.

METHODS: A human hepatocellular carcinoma cell line stably transfected with a bile acid transporter (Huh-BAT cells), were used in this study. Apoptosis was quantified using 4’,6-diamidino-2-phenylindole dihydrochloride staining and the APO Percentage apoptosis assay, and its signaling cascades were explored by immunoblot analysis. Kinase signaling was evaluated by immunoblotting and by using selective inhibitors. It is also tried to identify hepatocyte apoptosis affected by the HMGB1 inhibitor, GL.

RESULTS: HMGB1 increased cellular apoptosis in Huh-BAT cells. HMGB1 led to increased cytochrome c release from mitochondria into the cytosol, and induced the cleavage of procaspase 3. However, it did not affect the activation of caspase 8. HMGB1-induced caspase 3 activation was significantly attenuated by the p38 inhibitor SB203580. GL significantly attenuated HMGB1-induced hepatocyte apoptosis. GL also prevented HMGB1-induced cytochrome c release and p38 activation in Huh-BAT cells.

CONCLUSION: The present study demonstrated that HMGB1 promoted hepatocyte apoptosis through a p38-dependent mitochondrial pathway. In addition, GL had an anti-apoptotic effect on HMGB1-treated hepatocytes.

Monoclonal antibody to intercellular adhesion molecule-1 as a novel therapy for preeclampsia: preliminary results from a rat model

OBJECTIVE

Preeclampsia is a prevalent and potentially devastating complication of pregnancy. Intercellular adhesion molecule-1 (ICAM-1) was reported to be involved in the pathogenesis of the disease. Therefore we hypothesized anti-ICAM-1 monoclonal antibody (mAb) could be a therapeutic choice for preeclampsia. The objective of this study was to evaluate its therapeutic effects using a rat model of preeclampsia.

METHODS

Timed pregnant Wistar rats were intravenously injected endotoxin and then randomized to receive either anti-ICAM-1 mAb or saline. The effects of antibody on blood pressure, urinary protein, levels of alanine aminotransferase (ALT), blood urea nitrogen (BUN), creatinine, uric acid, weight of placenta were measured. Pregnancy outcomes were evaluated.

RESULTS

Anti-ICAM-1 mAb significantly decreased the levels of blood pressure, urinary protein, maternal BUN, creatnine and uric acid comparing with untreated preeclamptic rats. And the antibody therapy significantly improved pregnancy outcomes. After five days of mAb treatment, most of the parameters in mAb-treated group approached normal levels.

CONCLUSIONS

Our data prove anti-ICAM-1 mAb therapy as a promising choice for preeclampsia.

Hepatic protection by glycyrrhizin and inhibition of iNOS expression in concanavalin A-induced liver injury in mice

OBJECTIVE AND DESIGN

In this study, the possible protective effect of glycyrrhizin (GL), an active compound derived from licorice root, was examined on T cell-mediated liver injury in mice.

MATERIALS AND METHODS

Mice were subjected to liver injury by intravenous injection of concanavalin A (Con A). They had been treated with GL (i.p.) 30 min before the injection. Liver injury was estimated by measuring serum levels of alanine aminotransaminase (ALT) and aspartate aminotransaminase (AST), and by examining liver sections with hematoxylin-eosin staining. Expression of inducible nitric oxide synthase (iNOS) mRNA and protein in the liver was determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting.

RESULTS

Serum transaminases and hepatic iNOS levels increased with time after Con A treatment. Expression of iNOS mRNA in the liver was elevated for up to 8 h, and at 8 h, GL (ED(50): 10.5 mg/kg) suppressed the increases in AST and ALT in response to Con A. An increase in iNOS mRNA expression and protein was inhibited by treatment with GL. Furthermore, GL inhibited cell infiltration and the degeneration of hepatocytes in the liver of Con A-treated mice.

CONCLUSION

The present study suggests that the prevention by GL of Con A-induced hepatitis is due partly to the modulation of hepatic iNOS induction and of degeneration of hepatocytes.

Oxidative stress and glaucoma: injury in the anterior segment of the eye

The perturbation of the pro-oxidant/antioxidant balance can lead to increased oxidative damage, especially when the first line of antioxidant defense weakens with age. Chronic changes in the composition of factors present in aqueous or vitreous humor may induce alterations both in trabecular cells and in cells of the optic nerve head. Free radicals and reactive oxygen species are able to affect the cellularity of the human trabecular meshwork (HTM). These findings suggest that intraocular pressure increase, which characterizes most glaucomas, is related to oxidative and degenerative processes affecting the HTM and, more specifically, its endothelial cells. This supports the theory that glaucomatous damage is the pathophysiological consequence of oxidative stress. Glaucomatous subjects might have a genetic predisposition, rendering them more susceptible to reactive oxygen species-induced damage. It is likely that specific genetic factors contribute to both the elevation of IOP and susceptibility of the optic nerve/retinal ganglion cells (RGCs) to degeneration. Thus, oxidative stress plays a fundamental role during the arising of glaucoma-associated lesions, first in the HTM and then, when the balance between nitric oxide and endothelins is broken, in neuronal cell. Vascular damage and hypoxia, often associated with glaucoma, lead to apoptosis of RGCs and may also contribute to the induction of oxidative damage to the HTM. On the whole, these findings support the hypothesis that oxidative damage is an important step in the pathogenesis of primary open-angle glaucoma and might be a relevant target for both prevention and therapy.