Glycyrrhizic acid treatment ameliorates anxiety-like behaviour via GLT1 and Per1/2-dependent pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: As a traditional Chinese medicinal herb, Glycyrrhiza. URALENSIS: Fisch. (licorice root, chinese name: Gancao) has a variety of medicinal values and is widely used clinically. Its main active ingredient, glycyrrhizic acid (GA), is believed to have a neuroprotective effect. However, the underlying biological mechanisms of GA on stress-induced anxiety disorders are still unclear. AIM OF THE STUDY: To investigate the anti-anxiety effect of GA and its underlying mechanism. METHODS: We selected the anxiety model induced by repeated chronic restraint stress (CRS) for 2 h on each of 7 consecutive days. GA (4, 20, 100 mg/kg) was injected intraperitoneally once daily for 1 week. The potential GA receptors were identified using whole-cell patches and computer-assisted docking of molecules. High-throughput RNA sequencing, adeno-associated virus-mediated gene regulation, Western blotting, and RT-qPCR were used to assess the underlying molecular pathways. RESULTS: GA alleviate depression-like and anxiety-like behaviors in CRS mice. GA decreased synaptic transmission by facilitating glutamate reuptaking in mPFC. Meanwhile, long-term GA treatment increased the expression of clock genes Per1 and Per2. Suppressing both Per1 and Per2 abolished the anxiolytic effects of GA treatment. CONCLUSION: Our study suggests that GA may be developed for the treatment of stress-induced anxiety disorders, and its mechanism is related to GLT1 and Per1/2-dependent pathways. This presents a novel approach to discovering potent therapeutic drugs.

Glycyrrhizin and the Related Preparations: An Inspiring Resource for the Treatment of Liver Diseases.

Liver diseases and their related complications endanger the health of millions of people worldwide. The prevention and treatment of liver diseases are still serious challenges both in China and globally. With the improvement of living standards, the prevalence of metabolic liver diseases, including non-alcoholic fatty liver disease and alcoholic liver disease, has increased at an alarming rate, resulting in more cases of end-stage liver disease. Therefore, the discovery of novel therapeutic drugs for the treatment of liver diseases is urgently needed. Glycyrrhizin (GL), a triterpene glycoside from the roots of licorice plants, possesses a wide range of pharmacological and biological activities. Currently, GL preparations (GLPs) have certain advantages in the treatment of liver diseases, with good clinical effects and fewer adverse reactions, and have shown broad application prospects through multitargeting therapeutic mechanisms, including antisteatotic, anti-oxidative stress, anti-inflammatory, immunoregulatory, antifibrotic, anticancer, and drug interaction activities. This review summarizes the currently known biological activities of GLPs and their medical applications in the treatment of liver diseases, and highlights the potential of these preparations as promising therapeutic options and their alluring prospects for the treatment of liver diseases.

Efficacy and safety of compound glycyrrhizin in combination with conventional therapy in treatment of vitiligo: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Vitiligo is an acquired chronic depigmentary disorder affecting approximately 0.5% to 1% of individuals worldwide. The compound glycyrrhizin (CG), a complementary medicine, has been reported for treatment of vitiligo, but the evidence has not been systematically evaluated. We systematically assessed the efficacy and safety of CG in combination with conventional therapy for the treatment of vitiligo. METHODS: We searched Embase, Web of Science, PubMed, The Cochrane Library, Chinese BioMedical Literature Database (CBM), Wanfang Data, China National Knowledge Infrastructure (CNKI), and VIP information from inception to July 2022. Randomized controlled trials comparing CG combined with conventional therapy with conventional therapy alone for vitiligo were included in our analysis. The primary outcome was treatment response, which defined as >50% repigmentation rate of vitiligo after treatment. The secondary outcome was incidence of adverse events. Meta-analysis was performed using the Review Manager 5.4 software. Statistical heterogeneity was evaluated with chi-square and I2 statistics, dichotomous data were expressed as risk ratios (RR) with 95% confidence intervals using the Mantel-Haenszal method. RESULTS: Thirty-nine studies enrolling with 3994 participants were subjected to this review. The results of our meta-analysis indicated that addition of CG had superior effectiveness on repigmentation rate than phototherapy (RR = 1.28; P < .001), immunosuppressant (RR = 1.76; P < .001), traditional Chinese medicine (RR = 1.38; P < .001), combination of phototherapy and immunosuppressant (RR = 1.42; P < .001), and combination of phototherapy and traditional Chinese medicine (RR = 1.37; P < .001). In addition, CG did not increase the incidence of adverse events for vitiligo (RR = 0.79; P = .05). CONCLUSIONS: CG as a complementary medicine has a potential benefit in treatment of vitiligo. However, since the methodological flaws in the studies we included, more high-quality randomized controlled trials are warranted.

Evaluation of the Antiviral Efficacy of Subcutaneous Nafamostat Formulated with Glycyrrhizic Acid against SARS-CoV-2 in a Murine Model.

The ongoing COVID-19 pandemic highlights the urgent need for effective antiviral agents and vaccines. Drug repositioning, which involves modifying existing drugs, offers a promising approach for expediting the development of novel therapeutics. In this study, we developed a new drug, MDB-MDB-601a-NM, by modifying the existing drug nafamostat (NM) with the incorporation of glycyrrhizic acid (GA). We assessed the pharmacokinetic profiles of MDB-601a-NM and nafamostat in Sprague-Dawley rats, revealing rapid clearance of nafamostat and sustained drug concentration of MDB-601a-NM after subcutaneous administration. Single-dose toxicity studies showed potential toxicity and persistent swelling at the injection site with high-dose administration of MDB-601a-NM. Furthermore, we evaluated the efficacy of MDB-601a-NM in protecting against SARS-CoV-2 infection using the K18 hACE-2 transgenic mouse model. Mice treated with 60 mg/kg and 100 mg/kg of MDB-601a-NM exhibited improved protectivity in terms of weight loss and survival rates compared to the nafamostat-treated group. Histopathological analysis revealed dose-dependent improvements in histopathological changes and enhanced inhibitory efficacy in MDB-601a-NM-treated groups. Notably, no viral replication was detected in the brain tissue when mice were treated with 60 mg/kg and 100 mg/kg of MDB-601a-NM. Our developed MDB-601a-NM, a modified Nafamostat with glycyrrhizic acid, shows improved protectivity against SARS-CoV-2 infection. Its sustained drug concentration after subcutaneous administration and dose-dependent improvements makes it a promising therapeutic option.

Comparative effectiveness of glycyrrhizic acid preparations aimed at improving liver function of patients with chronic hepatitis B: A network meta-analysis of 53 randomized controlled trials.

BACKGROUND AND OBJECTIVES: Entecavir (ETV) has disadvantages, such as poor improvement in liver function, during the treatment of Chronic hepatitis B (CHB). Thus ETV is often used in clinical therapy with glycyrrhizic acid (GA) preparations. However, due to the lack of reliable and direct clinical studies, it remains controversial whether glycyrrhizic acid preparations have the best efficacy in CHB. Therefore, we aimed to compare and rank the different GA preparations in the treatment of CHB using network meta-analysis (NMA). METHODS: We systematically searched MEDLINE, EMBASE, Cochrane Library, Web of Science, China national knowledge internet (CNKI), Wanfang, VIP, and SinoMed databases as of August 4, 2022. Literature was screened according to predefined inclusion and exclusion criteria to extract meaningful information. A Bayesian approach was used for random effects model network meta-analysis, and Stata 17 software was used for data analysis. RESULTS: From 1074 papers, we included 53 relevant randomized clinical trials (RCTs). For the primary outcome, we used the overall effective rate in assessing the effectiveness of treatment for CHB (31 RCTs including 3007 patients): CGI, CGT, DGC and MgIGI significantly reduced the incidence of overall response compared to controls (RRs range from 1.16 to 1.24); SUCRA results showed that MgIGI was the best (SUCRA 0.923). In terms of secondary outcomes, we assessed the effect of treatment for CHB according to the level of reduction in ALT and AST: for ALT (37 RCTs including 3752 patients), CGI, CGT, DGC, DGI and MgIGI significantly improved liver function index compared to controls (MD range from 14.65 to 20.41); SUCRA results showed that CGI was the best (SUCRA 0.87); for AST, GI, CGT, DGC, DGI and MgIGI significantly improved liver function index compared to the control group (MD range from 17.46 to 24.42); SUCRA results showed that MgIGI was the best (SUCRA 0.871). CONCLUSION: In this study, we verified that the combination of GA and Entecavir is more effective than entecavir monotherapy in the treatment of hepatitis B. MgIGI and CGI showed clinically significant effects on liver function recovery compared with other GA preparations. MgIGI appeared to be the best choice among all GA preparations for the treatment of CHB. Our study provides some references for the treatment of CHB.

Combination of magnetic hyperthermia and immunomodulators to drive complete tumor regression of poorly immunogenic melanoma.

Hyperthermia using magnetic nanoparticles enables tumor-specific heating and can destroy tumor tissues. This approach works as in situ vaccination with tumor antigens released from dying tumor cells. However, in situ vaccination caused by magnetic hyperthermia is often insufficient to induce complete regression of poorly immunogenic tumors surrounded by an immunosuppressive microenvironment. In this study, we explored a novel strategy for immunotherapy using magnetic hyperthermia to regress poorly immunogenic melanoma. Magnetic hyperthermia induced tumor cell death in a B16-F10 melanoma mouse model. After hyperthermia treatment, we found elevated levels of HMGB1, which is known to be released from dying cells to promote inflammation, and the proinflammatory cytokine TNF-α was increased in serum of the mice. Systemic administration of glycyrrhizin, an HMGB1 inhibitor, reduced the levels of TNF-α in serum and successfully delayed the regrowth of tumors after magnetic hyperthermia. To achieve complete tumor regression, TLR9 activation by intratumor injection of CpG was combined with systemic administration of anti-PD-1 antibody and anti-CTLA-4 antibody. The combination therapy of magnetic hyperthermia at 46°C with the immunomodulators (glycyrrhizin+CpG+anti-PD-1+anti-CTLA-4) achieved complete tumor regression in 80% of growing 5-mm B16-F10 tumors. These findings have important implications for the development of novel cancer immunotherapy using magnetic hyperthermia for poorly immunogenic tumors.

Glycyrrhizic Acid and Its Derivatives: Promising Candidates for the Management of Type 2 Diabetes Mellitus and Its Complications.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease, which is characterized by hyperglycemia, chronic insulin resistance, progressive decline in ß-cell function, and defect in insulin secretion. It has become one of the leading causes of death worldwide. At present, there is no cure for T2DM, but it can be treated, and blood glucose levels can be controlled. It has been reported that diabetic patients may suffer from the adverse effects of conventional medicine. Therefore, alternative therapy, such as traditional Chinese medicine (TCM), can be used to manage and treat diabetes. In this review, glycyrrhizic acid (GL) and its derivatives are suggested to be promising candidates for the treatment of T2DM and its complications. It is the principal bioactive constituent in licorice, one type of TCM. This review comprehensively summarized the therapeutic effects and related mechanisms of GL and its derivatives in managing blood glucose levels and treating T2DM and its complications. In addition, it also discusses existing clinical trials and highlights the research gap in clinical research. In summary, this review can provide a further understanding of GL and its derivatives in T2DM as well as its complications and recent progress in the development of potential drugs targeting T2DM.

Identification of the Mechanism of Matrine Combined with Glycyrrhizin for Hepatocellular Carcinoma Treatment through Network Pharmacology and Bioinformatics Analysis.

Matrine and glycyrrhizin are representative active ingredients of traditional Chinese medicine (TCM) used in clinical practice. Studies have demonstrated that matrine has antitumor pharmacological effects and that glycyrrhizin protects liver function. However, the potential bioactive compounds and mechanisms remain unknown, as well as whether they have synergistic effects in killing cancer cells and protecting liver cells. To investigate the synergistic effects and mechanism of matrine combined with glycyrrhizin in hepatocellular carcinoma (HCC) treatment, we used both network pharmacology and bioinformatics analyses. First, the chemical gene interaction information of matrine and glycyrrhizin was obtained from the PubChem database. The pathogenic genes of HCC were accessed from five public databases. The RNA sequencing data and clinical information of HCC patients were downloaded from The Cancer Genome Atlas (TCGA). Next, the overlapping genes among the potential targets of matrine and glycyrrhizin and HCC-related targets were determined using bioinformatics analysis. We constructed the drug-target interaction network. Prognosis-associated genes were acquired through the univariate Cox regression model and Lasso-Cox regression model. The results were verified by the International Cancer Genome Consortium (ICGC) database. Finally, we predicted the immune function of the samples. The drug-target interaction network consisted of 10 matrine and glycyrrhizin targets. We selected a Lasso-Cox regression model consisting of 3 differentially expressed genes (DEGs) to predict the efficacy of the combination in HCC. Subsequently, we successfully predicted the overall survival of HCC patients using the constructed prognostic model and investigated the correlation of the immune response. Matrine and glycyrrhizin have synergistic effects on HCC. The model we obtained consisted of three drug-target genes by Lasso-Cox regression analysis. The model independently predicted the combined effect of matrine and glycyrrhizin in HCC treatment and OS, which will be helpful for guiding clinical treatment. The prognostic model was correlated with the immune cells and immune checkpoints of patients, which had an adjuvant effect on HCC immunotherapy. Matrine and glycyrrhizin can have therapeutic effects on HCC by promoting the production or enhancing the core gene activity in the drug network and improving the immune system function of patients.

Glycyrrhizin and boswellic acids, the golden nutraceuticals: multitargeting for treatment of mild-moderate COVID-19 and prevention of post-COVID cognitive impairment.

Breakthrough infections have been reported in fully vaccinated persons. Furthermore, rebound symptoms have been reported following the new FDA granted emergency use to combat SARS-CoV-2. Glycyrrhizin (GR) and boswellic acids (BAs) combination has been shown to have highly successful actions against COVID-19 in our recent clinical trial. However, the study is limited by the small sample size, and therefore, the aim of this article is to comprehensively evaluate recent evidence on the efficacy of GR and BAs in preventing the development of COVID-19 in patients with mild and moderate infections and in preventing post-COVID-19 cognitive impairment, which is the most important symptom after recovery from Covid-19 disease. We have reviewed and discussed information published since the outbreak of the COVID-19 pandemic until July 2022 on preclinical (in vivo, in vivo and bioinformatics) and clinical studies related to the antiviral, anti-inflammatory and immunomodulatory activity of Gr and BAs. Sixteen studies were performed to determine the efficacy of GR against SARS-CoV-2. Ten studies were used primarily for in vitro and in vivo assays and six used molecular docking studies. However, the antiviral activity of BAs against SARS-CoV-2 was determined in only five studies using molecular modeling and bioinformatics. All these studies confirmed that GR n and BAs have strong antiviral activity and can be used as a therapeutic agent for COVID-19 and as a protective agent against SARS-CoV-2. They may act by inhibiting the main protease SARS-CoV-2 (Mpro) responsible for replication and blocking spike protein-mediated cell entry. Only seven rigorously designed clinical trials regarding the usefulness of GR, BAs or their combinations in the treatment of COVID-19 have been published as of July 2022. Although there is no clinical study regarding the treatment of cognitive impairment after COVID-19 that has been published so far, several preclinical and clinical studies have demonstrated the potential effect of GR and BAs in the prevention and treatment of cognitive impairment by inhibiting the activity of several molecules that activate inflammatory signaling pathway. In conclusion, the findings of our study documented the beneficial use of GR and BAs to treat SARS-CoV-2 and its variants and prevent post-COVID cognitive impairment. However, it warrants further studies with a larger randomized sample size to ensure that the studies have sufficient evidence of benefits against COVID-19 and post-COVID-19 symptoms.

Meta-analysis of the efficacy of glycyrrhizin for postoperative liver preservation in patients with liver cancer.

Objective: This meta-analysis comprehensively summarizes the current clinical research on compound glycyrrhizin (CG) treatment for liver cancer and protecting liver function to guide clinical treatment. Methods: Eighteen English-language articles were retrieved from PubMed, SinoMed, Cochrane, Embase, Web of Science, and three Chinese databases: The Wan Fang database, China National Knowledge Infrastructure (CNKI), and the VIP database. Results: CG treatment improved the patient's alanine aminotransferase (ALT) level (in the metastatic liver cancer group: mean deviation (MD) = -13.78, 95% confidence interval (CI) = [-17.29, 10.27]; in the primary liver cancer group: MD = -32.15, 95% CI = [-35.48, 28.81]); aspartate aminotransferase (AST) level (in the primary liver cancer group: MD = -21.63, 95% CI = [-24.29, 18.96]; in the metastatic liver cancer group: MD = -15.64, 95% CI = [-19.08, -12.20]); serum total bilirubin (TBIL) level (MD = -1.61, 95% CI = [-2.71, -0.51]); and serum albumin (ALB) level (MD = 2.80, 95% CI = [1.85, 3.74]). CG treatment was efficient than the control (relative risk [RR] = 1.66, 95% CI = [1.35, 2.04]). Although adverse reactions, including fever, were higher than in the control group (RR = 1.13, 95% CI = [0.89, 1.43]), they were controllable. Conclusion: CG affects liver preservation in treating liver cancer, which can reduce ALT, AST, and TBIL levels in patients; increase the ALB level; and protect liver cells. The CG-treated group showed improvement compared with the control group; although adverse reactions occurred in the treated group, the duration was shortened.

Effect of Loaded Glycyrrhizic Acid on PLGA Nano-particle on Treatment of Allergic Asthma.

Asthma is considered a complex disease of the respiratory system that is characterized by bronchoconstriction, airway inflammation, cough, dyspnea, and wheezing. Allergic reactions are the main reason behind asthma which is known as an important health problem with a high rate of morbidity and mortality in patients with respiratory diseases. Liquorice, the root of Glycyrrhiza, is primarily effective for asthma which is widely used in herbal medicine. In the present study, we designed nano-particles that carry Glycyrrhizic acid as the effective component of Liquorice. After Poly (D,L-lactide-co-glycolic acid) PLGA nanoparticle preparation and Glycyrrhizic acid loading, the morphology of the nanoparticle, the electric charge distribution, and drug-releasing ability were studied. Then the effect of Glycyrrhizic acid-PLGA on the animal model of allergic asthma was investigated. Glycyrrhizic acid-nanoparticle had a mean±SD size of 350±50 nm. about 67% of the effective component was released after 10 h. The interleukin (IL)-4, IL-5, IL-13, and IL-25 levels and the Muc5ac mRNA expression were decreased in the Glycyrrhizic acid-PLGA treated group. In addition, a significant decline was observed in goblet cell hyperplasia, mucus hyper-secretion, and eosinophilic inflammation around bronchi and vessels of the nano-drug treated group, compared with the asthmatic group. We found that Glycyrrhizic acid-PLGA nanoparticle had an anti-asthma effect which may be used as a new drug to cure asthma. It can prevent bronchial obstruction, breathlessness, and asthma attacks.

Diammonium Glycyrrhizinate Preparation for Liver Function Recovery in Chronic Hepatitis B in China: A Meta-analysis with Trial Sequential Analysis.

BACKGROUND: The treatment of chronic hepatitis B (CHB) comprises a global medical problem, and the first-line clinical drugs have obvious shortcomings. The use of the plant extract diammonium glycyrrhizinate (DG) in food and medicine has gradually widened because of its safety and effectiveness. DG is mainly used for liver-disease treatment in clinical practice, but DG intervention for CHB lacks systematic evidence. METHODS: The included randomized controlled trials were analyzed by comparator and control respectively for alanine aminotransferase (ALT), aspartate transaminase (AST), total bilirubin (TBIL) levels, hepatitis B virus DNA negative conversion ratio, and total effective rate, and subgroup analysis was conducted for intervention time, intervention dosage form, comparator drug, and combination drug, among others. Trial sequential analysis was used to verify the results. RESULT: DG could effectively reduce ALT, AST, TBIL, and other liver-function indexes and had a definite effect on liver-function recovery. From the beginning of the intervention to 3 months, the effect was significantly better than that of conventional treatment. Compared with other drugs, different dosage forms had differences in efficacy, and DG enteric-coated capsules and injections were lower than compound glycyrrhizin and magnesium isoglycyrrhizin. Meanwhile, DG capsules had no significant difference from them. Meanwhile, trial sequential analysis of the main results confirmed the reliability of the conclusion. CONCLUSION: To our knowledge, this was the first relatively complete meta-analysis and systematic evaluation of the efficacy of DG intervention for CHB; liver-function recovery was discussed in the context of traditional Chinese medicine thinking, and DG's therapeutic effect on CHB was defined.

Glycyrrhizin alleviates sepsis-induced acute respiratory distress syndrome via suppressing of HMGB1/TLR9 pathways and neutrophils extracellular traps formation.

BACKGROUND: Neutrophil extracellular traps (NETs) are involved in the development of sepsis-induced acute respiratory distress syndrome (ARDS). Glycyrrhizin (GL), the main active ingredient of the traditional Chinese medicine Glycyrrhiza glabra, has anti-inflammatory, anti-viral, and immunomodulatory effects. OBJECTIVE: The study aims to explore the efficacy and potential mechanism of GL on sepsis-induced ARDS in mice. MATERIALS AND METHODS: Mice were randomly divided into 3 groups: Control, CLP, and GL + CLP. Mice sepsis ARDS model was induced by cecal ligation and puncture (CLP) followed by intraperitoneal GL treatment. Then, the 7-day survival rate of mice was recorded. The lung function of mice was determined by whole-body plethysmography. Lung pathology and scores were observed by hematoxylin-eosin staining. The wet/dry ratio (W/D) of the lung was measured by weighing method. The protein concentration in bronchoalveolar lavage fluid (BALF) was measured by the BCA method. NETs formation in lung tissue was detected by immunofluorescence. Furthermore, HMGB1、TLR9、MyD88 and IL6 expression in lung tissue were detected by western blot and by quantitative real-time PCR, respectively. RESULTS: The results showed that GL improved the survival rate, attenuated lung tissue injury and reduced the expression of inflammatory factors in mice with CLP-induced sepsis. Meanwhile, we confirmed that GL could inhibit TLR9 / MyD88 activation from reducing NETs formation by decreasing HMGB1 expression. The formation of NETs is regulated by HMGB1 / TLR9 / MyD88. In addition, GL improved lung function in mice with sepsis-induced ARDS. Lung function suggested that GL increased alveolar ventilation, alleviated ventilator fatigue and reduced airway resistance in mice with ARDS induced by sepsis. CONCLUSIONS: GL ameliorated sepsis-induced ARDS and reduced the NETs formation in lung tissues, which may be associated with the inhibition of the HMGB1 / TLR9 pathway.

Co-treatment with natural HMGB1 inhibitor Glycyrrhizin exerts neuroprotection and reverses Parkinson's disease like pathology in Zebrafish.

ETHNOPHARMACOLOGICAL RELEVANCE: Parkinson's disease (PD) is the second most devastating age-related neurodegenerative diseases after Alzheimer diseases (AD) and is characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN) and aggregation of α-synuclein (α-syn). The precise etiology of PD is not yet fully understood and lacks the disease-modifying therapeutic strategies that could reverse the ongoing neurodegeneration. In the quest of exploring novel disease modifying therapeutic strategies, natural compounds from plant sources have gained much attention in recent days. Glycyrrhizin (GL) is the main active ingredient of the roots and rhizomes of licorice (Glycyrrhiza glabra L), which are generally used in the treatment of inflammatory diseases or as a tonifying herbal medicine. In Persia, GL is a conventional neuroprotective agent that are used to treat neurological disorders. The traditional use of GL in Japan is to treat chronic hepatitis B. In addition, GL is a natural inhibitor of high mobility group box 1 (HMGB1) which has exerted neuroprotective effect against several HMGB1 mediated pathological conditions. AIM OF THE STUDY: The study is aimed to evaluate therapeutic effect of GL against PD in zebrafish. MATERIAL AND METHODS: PD in zebrafish larvae is induced by administration of neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Apoptosis was assessed with TUNEL assay. Gene expression was performed to assess the modulation in genes related to neuroinflammatory and autophagy. RESULTS: We observed that GL co-treatment increased the length of DA neurons, decreased the number of apoptotic cells in zebrafish brain, and inhibited the loss of vasculature and disorganized vasculature induced by MPTP. GL co-treatment relieved the MPTP-induced locomotor impairment in zebrafish. GL co-treatment suppressed MPTP-induced upregulated mRNA expression of inflammatory markers such as hmgb1a, tlr4b, nfκb, il1ß, and il6. GL co-treatment suppressed the autophagy related genes α-syn and atg5 whereas increased the mRNA expression level of parkin and pink1. In addition, molecular docking study reveals that GL has binding interaction with HMGB1, TLR4, and RAGE. CONCLUSION: Hence, the effect of GL co-treatment on MPTP-induced PD-like condition in zebrafish is to alleviate apoptosis and autophagy, as well as suppress inflammatory responses.

Oncopreventive and oncotherapeutic potential of licorice triterpenoid compound glycyrrhizin and its derivatives: Molecular insights.

Licorice (Glycyrrhiza glabra) is a well-known natural herb used to treat different ailments since ancient times. Glycyrrhizin (GL), which is the primary triterpenoid compound of licorice extract, has been known to have broad-spectrum pharmacological effects. GL is cleaved into glucuronide and the aglycone, glycyrrhetinic acid (GA), which exists in two stereoisomeric forms: 18α- and 18ß-GA. It is well documented that GL and GA have great potential as anti-inflammatory, anticancer, antiviral, anti-diabetic, antioxidant, and hepatoprotective agents. Studies undertaken during the coronavirus disease 2019 pandemic suggest that GL is effective at inhibiting the viral replication of severe acute respiratory syndrome coronavirus 2. The anticancer effects of GL and GA involve modulating various signaling pathways, such as the phosphatase and tensin homolog/phosphatidylinositol 3-kinase/protein kinase B pathway, the mitogen-activated protein kinase, and the mammalian target of rapamycin/signal transducer and activator of transcription 3, which are mainly involved in regulating cancer cell death, oxidative stress, and inflammation. The potential of GL and GA in preventing cancer development and suppressing the growth and invasion of different cancer types has been reviewed in this paper. This review also provides molecular insights on the mechanism of action for the oncopreventive and oncotherapeutic effects of GL and its derivative, GA, which could help develop more specific forms of these agents for clinical use.

Glycyrrhizic acid ameliorates submandibular gland oxidative stress, autophagy and vascular dysfunction in rat model of type 1 diabetes.

The burden of diabetes mellitus (DM) and associated complications is increasing worldwide, affecting many organ functionalities including submandibular glands (SMG). The present study aims to investigate the potential ameliorative effect of glycyrrhizic acid (GA) on diabetes-induced SMG damage. Experimental evaluation of GA treatment was conducted on a rat model of type I diabetes. Animals were assigned to three groups; control, diabetic and GA treated diabetic groups. After 8 weeks, the SMG was processed for assessment of oxidative stress markers, autophagy related proteins; LC3, Beclin-1 and P62, vascular regulator ET-1, aquaporins (AQPs 1.4 and 5), SIRT1 protein expressions in addition to LC3 and AQP5 mRNA expressions. Also, parenchymal structures of the SMG were examined. GA alleviated the diabetes-induced SMG damage via restoring the SMG levels of oxidative stress markers and ET-1 almost near to the normal levels most probably via regulation of SIRT1, AQPs and accordingly LC-3, P62 and Beclin-1levels. GA could be a promising candidate for the treatment of diabetes-induced SMG damage via regulating oxidative stress, autophagy and angiogenesis.

Glycyrrhizin ameliorating sterile inflammation induced by low-dose radiation exposure.

Glycyrrhizin (GL) is a direct inhibitor of HMGB1 which acts as an alarmin when excreted into the extracellular space. High-dose radiation in radiotherapy induces collateral damage to the normal tissue, which can be mitigated by GL inhibiting HMGB1. The purpose of this study was to assess changes in HMGB1 and pro-inflammatory cytokines and to evaluate the protective effect of GL after low-dose radiation exposure. BALB/c mice were irradiated with 0.1 Gy (n = 10) and 1 Gy (n = 10) with GL being administered to half of the mice (n = 5, respectively) before irradiation. Blood and spleen samples were harvested and assessed for oxidative stress, HMGB1, pro-inflammatory cytokines, and cell viability. HMGB1 and pro-inflammatory cytokines increased and cell viability decreased after irradiation in a dose-dependent manner. Oxidative stress also increased after irradiation, but did not differ between 0.1 Gy and 1 Gy. With the pretreatment of GL, oxidative stress, HMGB1, and all of the pro-inflammatory cytokines decreased while cell viability was preserved. Our findings indicate that even low-dose radiation can induce sterile inflammation by increasing serum HMGB1 and pro-inflammatory cytokines and that GL can ameliorate the sterile inflammatory process by inhibiting HMGB1 to preserve cell viability.

Food Enrichment with Glycyrrhiza glabra Extract Suppresses ACE2 mRNA and Protein Expression in Rats-Possible Implications for COVID-19.

Angiotensin converting enzyme 2 (ACE2) is a key entry point of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus known to induce Coronavirus disease 2019 (COVID-19). We have recently outlined a concept to reduce ACE2 expression by the administration of glycyrrhizin, a component of Glycyrrhiza glabra extract, via its inhibitory activity on 11beta hydroxysteroid dehydrogenase type 2 (11betaHSD2) and resulting activation of mineralocorticoid receptor (MR). We hypothesized that in organs such as the ileum, which co-express 11betaHSD2, MR and ACE2, the expression of ACE2 would be suppressed. We studied organ tissues from an experiment originally designed to address the effects of Glycyrrhiza glabra extract on stress response. Male Sprague Dawley rats were left undisturbed or exposed to chronic mild stress for five weeks. For the last two weeks, animals continued with a placebo diet or received a diet containing extract of Glycyrrhiza glabra root at a dose of 150 mg/kg of body weight/day. Quantitative PCR measurements showed a significant decrease in gene expression of ACE2 in the small intestine of rats fed with diet containing Glycyrrhiza glabra extract. This effect was independent of the stress condition and failed to be observed in non-target tissues, namely the heart and the brain cortex. In the small intestine we also confirmed the reduction of ACE2 at the protein level. Present findings provide evidence to support the hypothesis that Glycyrrhiza glabra extract may reduce an entry point of SARS-CoV-2. Whether this phenomenon, when confirmed in additional studies, is linked to the susceptibility of cells to the virus requires further studies.

Can Antiviral Activity of Licorice Help Fight COVID-19 Infection?

The phytotherapeutic properties of Glycyrrhiza glabra (licorice) extract are mainly attributed to glycyrrhizin (GR) and glycyrrhetinic acid (GA). Among their possible pharmacological actions, the ability to act against viruses belonging to different families, including SARS coronavirus, is particularly important. With the COVID-19 emergency and the urgent need for compounds to counteract the pandemic, the antiviral properties of GR and GA, as pure substances or as components of licorice extract, attracted attention in the last year and supported the launch of two clinical trials. In silico docking studies reported that GR and GA may directly interact with the key players in viral internalization and replication such as angiotensin-converting enzyme 2 (ACE2), spike protein, the host transmembrane serine protease 2, and 3-chymotrypsin-like cysteine protease. In vitro data indicated that GR can interfere with virus entry by directly interacting with ACE2 and spike, with a nonspecific effect on cell and viral membranes. Additional anti-inflammatory and antioxidant effects of GR cannot be excluded. These multiple activities of GR and licorice extract are critically re-assessed in this review, and their possible role against the spread of the SARS-CoV-2 and the features of COVID-19 disease is discussed.