Glycyrrhizin inhibits swine acute diarrhea syndrome coronavirus infection via the HMGB1/TLR4/JNK signal pathway

Swine acute diarrhea syndrome coronavirus (SADS-CoV), a newly discovered enteric coronavirus, is the etiological agent that causes severe clinical diarrhea and intestinal pathological damage in piglets. In this study, Vero E6 and IPI-2I cells were pretreated with different concentrations of glycyrrhizin (GLY) for 2 hours, and then infected with different concentrations of SADSCoV, aiming to investigate the inhibitory effect of GLY on SADS-CoV. Western blot and TCID50 results revealed a significantly decreased N protein expression and viral titer, indicating that GLY can inhibit the infection of SADS-CoV. Vero E6 and IPI-2I cells were pretreated with different concentrations of GLY for 2 hours and infected with SADS-CoV. Western blot results showed that when the concentration of GLY was 0.8 mmol/L, the expression of N protein decreased significantly, indicating that GLY inhibited the invasion of the virus. At first, cells were treated with 0.4 mmol/L GLY, and cell samples were collected at 2 hours, 6 hours and 12 hours after being infected with SADS-CoV for analysis, and the expression of N protein were found to be significantly reduced at all points, indicating that GLY had a significant inhibitory effect on the replication of the virus. GLY is a competitive inhibitor of high mobility group box 1 (HMGB1), and the receptors of HMGB1 mainly include TLR4 and RAGE. Based on this fact, the mutant plasmid at the key sites of HMGB1 (C45S, C106S, C45/106S) and the siRNA of the RAGE receptor were transfected to Vero E6 cells and infected with SADS-CoV, and the cell supernatant and samples were harvested. The western blot and TCID50 results showed that the expression of N protein and the virus titer were decreased, suggesting that GLY exerts its function by affecting the binding of HMGB1/TLR4/RAGE during SADS-CoV infection. To further explore the signaling pathway through which GLY functions, Vero E6 and IPI-2I cells were inoculated with SADS-CoV, and cell samples were harvested, western blot was used to detect the changes of MAPK proteins. The results showed that the protein expression levels of p-p38, p-JNK and p-ERK were up-regulated in the early and late stages, indicating that the MAPK pathway was activated by SADS-CoV infection. Vero E6 and IPI-2I were pretreated with different concentrations of GLY and TLR4 inhibitor TAK for 2 hours and infected with SADS-CoV. Protein samples were harvested and analysed by western blot which showed a decreased p-JNK and N proteins, while other proteins showed no significant changes. These results indicated that GLY and TAK regulated the phosphorylation of JNK but did not regulate the phosphorylation of p38 and ERK. Also, Vero E6 cells were treated with HMGB1 antibody, the siRNA of HMGB1 and HMGB1 mutants plasmid, and infected with SADS-CoV. Protein samples were harvested, western blot results showed that phosphorylation of JNK decreased, indicating that HMGB1 affected JNK phosphorylation. Finally, Vero E6 and IPI-2I cells were pretreated with different concentrations of JNK inhibitor SP600125 to infect SADS-CoV, western blot, TCID50 and IFA results showed that the expression of N protein and virus titer, as well as virus replication were reduced, indicating that SP600125 inhibited virus replication. In conclusion, our results revealed that GLY can inhibit in vitro replication of SADS- CoV, mainly through the HMGB1/TLR4/JNK signaling pathway. The discovery of this pathway provides theoretical support for the research of novel anti-SADS-CoV drugs.

In-silico screening of plant-derived natural compounds for their anti-COVID-19 potential

The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began in Wuhan, China, in December 2019 and quickly spread across the worldwide. It becomes a global pandemic and risk to the healthcare system of almost every nation around the world. In this study thirty natural compounds of 19 Indian herbal plants were used to analyze their binding with eight proteins associated with COVID -19. Based on the molecular docking as well as ADMET analysis, isovitexin, glycyrrhizin, sitosterol, and piperine were identified as potential herbal medicine candidates. On comparing the binding affinity with Ivermectin, we have found that the inhibition potentials of the Trigonella foenum-graecum (fenugreek), Glycyrrhiza glabra (licorice), Tinospora cordifolia (giloy) and Piper nigrum (black pepper) are very promising with no side-effects.

Network pharmacological mechanism of Runfei Ningshen Decoction in the treatment of insomnia caused by COVID-19

Objective: To study the mechanism of Runfei Ningshen Decoction in the treatment of insomnia caused by corona virus disease 2019(COVID-19) by using network pharmacology and molecular docking analysis. Methods: The chemical components and targets of Chinese medicinal materials of Runfei Ningshen Decoction in TCMSP, Batman, and CTD databases were searched. The relevant targets of novel coronavirus pneumonia and insomnia in Disgenet, GeneCards, CTD, and Malacards databases were searched. The component-target-disease network was established by using Cytoscape 3.2.1 software;The protein-protein intereation(PPI) network was constructed in string database. The common targets were enriched by using Cluster Profiler software package in R language software platform. The molecular docking of core targets related to insomnia caused by COVID-19 was carried out by using Discovery Studio 4.0 software. Results: 349 medicinal ingredients in Runfei Ningshen Decoction, 1 904 targets, 1 505 new coronavirus pneumonia-related targets, and 1 337 insomnia-related targets were collected. When the intersection of Venn diagrams were used, 404 common targets were obtained for the 2 diseases. 250 targets were intersected with the 2 diseases, and 33 core targets were screened out by the analysis of the interaction network between targets. Pathway enrichment analysis showed that Runfei Ningshen Decoction mainly acts on AKT1, INS, TP53, IL-6, key targets such as AKT1, INS, TP53, IL-6, JUN, CASP3, TNF, CAT, PTGS2 and CXCL8, which are involved in the important pathway processes such as human cytomegalovirus infection, fluid shear stress, and AGE-RAGE signaling pathways in complications of atherosclerosis and diabetes. The results of molecular docking showed that the core target has a high affinity with beta-sitosterol, 1-methoxy phaseolin, 3'-hydroxy-4'-O-methylglycyrrhizin, and anhydroicariin. The prescription treatment of insomnia caused by COVID-19 may be through the targets such as PTGS2, AR, PPARG, NOS2, HSP90 AA1 and so on. Conclusion: Runfei Ningshen Decoction can treat insomnia caused by COVID-19 by inhibiting IL-6 and TNF-a.

Role of Supplements in the Management of COVID-19 - A Comprehensive Review.

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) and patients with COVID-19 may be treated primarily with SARS CoV-2-targeting drugs and the therapeutic agents assisting in the management of COVID-19 complications. This review focuses on the supplements like vitamins, minerals, herbal constituents, and others that help prevent or manage negative outcomes among COVID-19 patients. The literature was searched in databases such as Medline/PubMed Central/PubMed, Google Scholar, Science Direct, EBSCO, Scopus, EMBASE, the Directory of Open Access Journals (DOAJ), and reference lists to identify relevant articles. The vitamins, including vitamin C, and vitamin D, minerals such as zinc, selenium, and copper, herbal constituents like thymoquinone, curcumin, naringenin, quercetin, and glycyrrhizin, and other supplements, including N-acetylcysteine and melatonin. Melatonin have been identified as having the potential to manage patients with COVID-19 along with standard care. Some of the ongoing clinical trials are investigating the effectiveness of different supplements among COVID-19 patients.

Molecular docking analysis of ten plant products for the inhibition of spike glycoprotein and prospective use as anti-COVID compounds

The threat of the COVID-19 pandemic has persisted unabated over the past two years. The current response to maintaining public health has been guided by the vaccination of the population. The success of this policy has been mixed COVID coming back in each region in waves driven by new variants. Given that boosted immune response to COVID-19 owing to the vaccine also having an expiration time, it is important to look at alternative options to protect against COVID-19. In this regard, bioactive substances commonly found in food or food additives present a viable option to shield against consequential COVID-19 infection. We investigate 10 bioactive plant products for possible antiviral use against the SARS-CoV-2 virus, which causes COVID-19 infection. We test these compounds by in silico docking to the Spike glycoprotein, one of the major determinants of COVID-19 infection. The AutoDock Vina software was used to scan and score the docking sites on a Spike protein ectodomain model. The top twenty hits were saved for each of the ten compounds and then the common and unique docking sites were delineated noting the putative binding affinity in each case. The results show that all ten plant products are high-affinity binders to the Spike protein, the S2 domain being the primary binding site. Very few binding interactions are found on the receptor binding domain, which means that topically used of these molecules such as in nasal spray would not be effective. In the ingestible form, the compounds can bind to the Spike molecule and disable it from driving virus-host fusion, its main function. It can thereby limit the cell-to-cell spread of the virus thus enforcing localization and clearance by the host immune system.

Advancing combination treatment with glycyrrhizin and boswellic acids for hospitalized patients with moderate COVID-19 infection: a randomized clinical trial.

Recent evidence points to a potential therapeutic role for glycyrrhizin(GR) and boswellic acids (BA) in the treatment of COVID-19 but conclusive evidence is lacking. Our aim is to investigate the efficacy of GR + BA versus placebo for the treatment of hospitalized patients with moderate SARS-CoV-2 or COVID-19 variants infection. The current study is a randomized, double-blind, placebo-controlled, single-center trial. Patients with SARS-CoV-2 or COVID-19 variants diagnosed by PCR test who were admitted to Sohag University hospital were eligible if they were at least 18 years of age and had moderate symptoms. Patients were randomly assigned to receive oral GR capsule (60 mg) and BA (200 mg) twice daily for 14 days or a matching placebo. All patients also received treatment with the institutional protocol for COVID-19. The primary outcome was mortality and time to recovery. Secondary outcome was clinical status score, 14 days after receiving study drugs. Adverse events from use of study drugs have been evaluated for up to 14 days. The trial is registered at ClinicalTrials.gov (Identifier NCT04487964). During the 6-month enrollment period (June-November, 2021) only 50 patients (54% women; median age 60 years, IQR 54-65) met eligibility and were randomly assigned. Evaluation of the primary outcome at 14 days showed that there were five deaths in the placebo group and no deaths in the GR + BA group. With regard to recovery time, it was significantly shorter (p = 0.0001) in the group receiving GR + BA capsule compared to the placebo group (median 7.0; IQR 6.0-8.0 days vs. median 12.5; IQR 12-20 days). Clinical status on the ordinal score scale as a secondary outcome showed a significant difference between the GR + BA group (median (IQR) score, 2 [2-3]) and placebo groups (mean (IQR) score, 3 [3-5.5]). There was a significant decrease in CRB (p = 0.000041) in GR + BA compared with the placebo group. In conclusion, this safe, inexpensive, antiviral, immunomodulating and anti-inflammatory combination may be considered for use in mild to moderate infections of SARS-CoV-2 or COVID-19 variants. The study is limited by the small sample size; therefore, larger randomized trials are required.

Glycyrrhizin as a promising kryptonite against SARS-CoV-2: Clinical, experimental, and theoretical evidences.

COVID-19 is the most devastating disease in recent times affecting most people globally. The higher rate of transmissibility and mutations of SARS-CoV-2 along with the lack of potential therapeutics has made it a global crisis. Potential molecules from natural sources could be a fruitful remedy to combat COVID-19. This systematic review highlights the detailed therapeutic implication of naturally occurring glycyrrhizin and its related derivatives against COVID-19. Glycyrrhizin has already been established for blocking different biomolecular targets related to the SARS-CoV-2 replication cycle. In this article, several experimental and theoretical evidences of glycyrrhizin and related derivatives have been discussed in detail to evaluate their potential as a promising therapeutic strategy against COVID-19. Moreover, the implication of glycyrrhizin in traditional Chinese medicines for alleviating the symptoms of COVID-19 has been reviewed. The potential role of glycyrrhizin and related compounds in affecting various stages of the SARS-CoV-2 life cycle has also been discussed in detail. Derivatization of glycyrrhizin for designing potential lead compounds along with combination therapy with other anti-SARS-CoV-2 agents followed by extensive evaluation may assist in the formulation of novel anti-coronaviral therapy for better treatment to combat COVID-19.

Phytochemicals in the Prevention and Treatment of SARS-CoV-2-Clinical Evidence.

The first case of SARS-CoV-2 infection was reported in December 2019. Due to the rapid spread of the disease and the lack of adequate therapy, the use of plants that have a long history in the treatment of viral infections has often been considered. The aim of this paper is to provide a brief review of the literature on the use of phytochemicals during the new pandemic. An extensive search of published works was performed through platforms Google Scholar, PubMed, Science Direct, Web of Science and Clinicaltrials.gov. Numerous preclinical studies on the use of phytochemicals (quercetin, curcumin, baicalin, kaempferol, resveratrol, glycyrrhizin, lycorine, colchicine) against SARS-CoV-2 have shown that these components can be effective in the prevention and treatment of this infection. Clinical research has proven that the use of black cumin and green propolis as well as quercetin has positive effects. As for other phytochemicals, in addition to preclinical testing which has already been carried out, it would be necessary to conduct clinical tests in order to assert their effectiveness. For those phytochemicals whose clinical efficacy has been proven, it would be necessary to conduct research on a larger number of patients, so that the conclusions are more representative.

Glycyrrhizin Inhibits SARS-CoV-2 Entry into Cells by Targeting ACE2.

Coronavirus Disease 2019 (COVID-19) is a highly infectious and pathogenic disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Early in this epidemic, the herbal formulas used in traditional Chinese medicine (TCM) were widely used for the treatment of COVID-19 in China. According to Venn diagram analysis, we found that Glycyrrhizae Radix et Rhizoma is a frequent herb in TCM formulas against COVID-19. The extract of Glycyrrhizae Radix et Rhizoma exhibits an anti-SARS-CoV-2 replication activity in vitro, but its pharmacological mechanism remains unclear. We here demonstrate that glycyrrhizin, the main active ingredient of Glycyrrhizae Radix et Rhizoma, prevents the coronavirus from entering cells by targeting angiotensin-converting enzyme 2 (ACE2). Glycyrrhizin inhibited the binding of the spike protein of the SARS-CoV-2 to ACE2 in our Western blot-based assay. The following bulk RNA-seq analysis showed that glycyrrhizin down-regulated ACE2 expression in vitro which was further confirmed by Western blot and quantitative PCR. Together, we believe that glycyrrhizin inhibits SARS-CoV-2 entry into cells by targeting ACE2.

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.

New Aspects of the Antioxidant Activity of Glycyrrhizin Revealed by the CIDNP Technique.

Electron transfer plays a crucial role in ROS generation in living systems. Molecular oxygen acts as the terminal electron acceptor in the respiratory chains of aerobic organisms. Two main mechanisms of antioxidant defense by exogenous antioxidants are usually considered. The first is the inhibition of ROS generation, and the second is the trapping of free radicals. In the present study, we have elucidated both these mechanisms of antioxidant activity of glycyrrhizin (GL), the main active component of licorice root, using the chemically induced dynamic nuclear polarization (CIDNP) technique. First, it was shown that GL is capable of capturing a solvated electron, thereby preventing its capture by molecular oxygen. Second, we studied the effect of glycyrrhizin on the behavior of free radicals generated by UV irradiation of xenobiotic, NSAID-naproxen in solution. The structure of the glycyrrhizin paramagnetic intermediates formed after the capture of a solvated electron was established from a photo-CIDNP study of the model system-the dianion of 5-sulfosalicylic acid and DFT calculations.

Efficacy and Safety of Novel Herbal Tablets in COVID-19 Patients in Hospital Stay Days, ICU Admission and Mortality Rate Thereof: An Ppen-Label, Single-Blind Randomized Clinical Trial

Background: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the super-spreading virus, has claimed hundreds of thousands of lives worldwide. Objectives: This study aimed to evaluate the effectiveness of the novel suggested herbal compound, formulated as compressed tablets, in reducing the length of hospital stay(LoS), intensive care unit (ICU) admission, and mortality in confirmed COVID-19 cases. Methods: Following an open-label, single-blind randomized clinical trial design, a total of 200 patients aged 18 65 admitted to Imam Reza hospital in Tabriz, northwest of Iran, were randomized to intervention and control groups in a1:1 ratio, i.e.,100 subjects in each group. The former received standard treatment along with the compressed herbal tablets, and the latter only received the standard treatment. Adverse reactions incidence within 180 days after the beginning of the intervention was set as the primary safety endpoint. The most important and active ingredients of the tablets were Terminalia chebula, Glycyrrhiza glabra, Anacyclus pyrethrum, Senna alexandrina, Ferrula asafoetida, Pistacia lentiscus, Zizyphus jujuba, Crocus sativus, Echinacea angustifolia, and Hyssopus officinalis. This trial is registered at the Iranian Registry of Clinical Trials (code: IRCT20200522047545N1). Results: Those in the intervention arm had significantly lower rates of LoS (7.38 vs. 9.45, P = 0.030), ICU admission (6 out of 100 vs. 32 out of 100, P= 0.000), and mortality (1 vs. 19 out of 100, P= 0.000). Conclusions: Our observations suggest that adequate improvement is provided by the prepared herbal compound along with substantial savings in hospitalization hoteling costs. While further multi-center studies with a larger sample size are needed to extend our knowledge regarding the effect of this new option, these novel clinical data may well provide a new alternative for the management of COVID-19 disease.

A SYSTEMATIC REVIEW OF EXPERIMENTAL AND CLINICAL STUDIES ON THE PHARMACOLOGY OF GLYCYRRHIZIN AND ITS DERIVATIVES

Glycyrrhizin and its derivatives (glycyrrhizic acid, etc.) are the key components of licorice root extracts (licorice) which can have anti-inflammatory and antiviral effects. A systematic analysis of 3264 publications on the studies of glycyrrhizin and its derivatives made it possible to characterize the range of pharmacological applications of drugs based on glycyrrhizin. The study highlights a number of relevant molecular and cellular mechanisms of action of glycyrrhizin, including regulation of the activity of T-lymphocytes, mast cells, neutrophils, macrophages, biosynthesis and secretion of pro-inflammatory and anti-inflammatory cytokines, lipoxins and prostaglandins. Glycyrrhizin dose-dependently activates receptor LXRa, inhibits the production of pro-inflammatory cytokines IL-6 and IL-8, suppresses the increased expression of HMGB1 receptor and pro-inflammatory cytokines TNF, IL-1ß and IL-6, blocks the NFkB-dependent signaling pathways MAPK and PI3K/Akt, inducible nitric oxide synthase, COX-2. Topical application of glycyrrhizin and its derivatives is promising for the treatment of inflammatory diseases of the mucous membranes and skin, including the diseases of bacterial, fungal and viral origin (allergic contact dermatitis, eczema, keratitis caused by Pseudomonas aeruginosa, papillomavirus, herpes virus (as well as herpes simplex, varicella zoster), SARS-CoV-2, etc. Glycyrrhizin and its derivatives inhibit the formation of biofilms of bacteria characterized by increased resistance to antibiotics and even to antiseptics. Due to the fact that glycyrrhizin induces CD4+ T-cells, it suppresses the production of type 2 cytokines and increases resistance to candidiasis. The study also describes the prospects for the use of glycyrrhizin in the treatment of genital warts. Conclusion: The results of the basic and clinical studies presented in this paper show the prospects for topical application of glycyrrhizin in various fields of medicine, including gynecological practice. © 2022, Bionika Media Ltd.. All rights reserved.

Recent advances in glycyrrhizin metabolism, health benefits, clinical effects and drug delivery systems for efficacy improvement; a comprehensive review.

BACKGROUND: Glycyrrhizin (GL) is a major active constituent of licorice root (Glycyrrhiza glabra) that is considered one of the oldest and most frequently employed botanicals in Chinese medicine and worldwide, with most effects attributed to its rich GL content. Structurally, GL a triterpene saponin that is widely used as a flavoring agent in foodstuffs and cosmetics, and also proposed for various clinical applications with a myriad of health benefits. Pharmacological and biological activities of GL include antiviral, anti-inflammatory, antioxidant, and anticancer activities (in vitro and in vivo). Currently, there is no comprehensive review on GL biological effects and its action mechanisms. PURPOSE: This review summarizes GL pharmacological actions from a molecular biology perception, presented on its metabolism and side effects based on in vitro, in vitro and clinical studies. Moreover, the potential of GL as a nanomedicine delivery system is also summarized. The progress in drug delivery research using GL presented herein is expected to provide a theoretical basis for developing other novel drugs formulations. METHODS: A systematic review was carried out in several electronic databases (Science Direct, SpringerLink, CNKI, PubMed, Web of Science, Elsevier, and Scopus), using the following key words: glycyrrhizin "AND" bioactivity "OR" clinic "OR" therapeutic "OR" drug delivery. This search included manuscripts published between 1989 and 2021. RESULTS: 126 researches were selected and summarized in this review. The analysis of these studies indicated that GL has antiviral activity against different viruses. Further, GL efficiently suppressed the respiratory manifestations associated with COVID-19 by reducing the expression of angiotensin converting enzyme 2 (ACE2) that employed by the virus as an entry point. Otherwise, GL was found to induce antioxidant, anti-inflammatory, immune-modulatory, and anticancer activity. Besides, diminution the particle size of GL to nanometer size significantly augments their action and biodistribution. CONCLUSION: This article summarizes the pharmacological actions of GL. The potential of GL as a nanomedicine delivery system is also presented. Nevertheless, most studies reported provide no deep insight of GL health effects warranting for more future studies to elucidate its action mechanism and potential therapeutic benefits through preclinical and clinical trials.

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.

Revisiting liquorice (Glycyrrhiza glabra L.) as anti-inflammatory, antivirals and immunomodulators: Potential pharmacological applications with mechanistic insight.

Background: Glycyrrhiza glabra L. (G. glabra) commonly known as liquorice is one of the highly exploited and utilized medicinal plant of the world. Since ancient times liquorice is considered as an auspicious and valuable traditional medicine across the world for treatment of various ailments. Method: Several electronic online scientific databases such as Science Direct, PubMed, Scopus, Scifinder, Google Scholar, online books and reports were assessed for collecting information. All the collected information was classified into different sections to meet the objective of the paper. Results: The electronic database search yielded 3908 articles from different countries. Out of them one ninety-eight articles published between 1956 and 2021 were included, corresponding to all detailed review on G. glabra and research on anti-inflammatories, antivirals and immunomodulatory through pre-clinical and clinical models. From all selective area of studies on G. glabra and its bioactive components it was established (including molecular mechanisms) as a suitable remedy as per the current requirement of pandemic situation arise through respiratory tract infection. Conclusion: Different relevant studies have been thoroughly reviewed to gain an insight on utility of liquorice and its bioactive constituents for anti-inflammatories, antivirals and immunomodulatory effects with special emphasized for prevention and treatment of COVID-19 infection with possible mechanism of action at molecular level. Proposed directions for future research are also outlined to encourage researchers to find out various mechanistic targets and useful value added products of liquorice in future investigations.

Glycyrrhizic Acid Inhibits SARS-CoV-2 Infection by Blocking Spike Protein-Mediated Cell Attachment.

Glycyrrhizic acid (GA), also known as glycyrrhizin, is a triterpene glycoside isolated from plants of Glycyrrhiza species (licorice). GA possesses a wide range of pharmacological and antiviral activities against enveloped viruses including severe acute respiratory syndrome (SARS) virus. Since the S protein (S) mediates SARS coronavirus 2 (SARS-CoV-2) cell attachment and cell entry, we assayed the GA effect on SARS-CoV-2 infection using an S protein-pseudotyped lentivirus (Lenti-S). GA treatment dose-dependently blocked Lenti-S infection. We showed that incubation of Lenti-S virus, but not the host cells with GA prior to the infection, reduced Lenti-S infection, indicating that GA targeted the virus for infection. Surface plasmon resonance measurement showed that GA interacted with a recombinant S protein and blocked S protein binding to host cells. Autodocking analysis revealed that the S protein has several GA-binding pockets including one at the interaction interface to the receptor angiotensin-converting enzyme 2 (ACE2) and another at the inner side of the receptor-binding domain (RBD) which might impact the close-to-open conformation change of the S protein required for ACE2 interaction. In addition to identifying GA antiviral activity against SARS-CoV-2, the study linked GA antiviral activity to its effect on virus cell binding.

Mechanism of the enhancing effect of glycyrrhizin on nifedipine penetration through a lipid membrane.

The saponin glycyrrhizin from liquorice root shows the ability to enhance the therapeutic activity of other drugs when used as a drug delivery system. Due to its amphiphilic properties, glycyrrhizin can form self-associates (dimers, micelles) and supramolecular complexes with a wide range of hydrophobic drugs, which leads to an increase in their solubility, stability and bioavailability. That is why the mechanism of the biological activity of glycyrrhizin is of considerable interest and has been the subject of intensive physical and chemical research in the last decade. Two mechanisms have been proposed to explain the effect of glycyrrhizin on drug bioavailability, namely, the increase in drug solubility in water and enhancement of the membrane permeability. Interest in the membrane-modifying ability of glycyrrhizic acid (GA) is also growing at present due to its recently discovered antiviral activity against SARS-CoV-2 Bailly and Vergoten (2020) [1]. In the present study, the passive permeability of the DOPC lipid membrane for the calcium channel blocker nifedipine was elucidated by parallel artificial membrane permeability assay (PAMPA) and full atomistic molecular dynamics (MD) simulation with free energy calculations. PAMPA experiments show a remarkable increase in the amount of nifedipine (NF) permeated with glycyrrhizin compared to free NF. In previous studies, we have shown using MD techniques that glycyrrhizin molecules can integrate into the lipid bilayer. In this study, MD simulation demonstrates a significant decrease in the energy barrier of NF penetration through the lipid bilayer in the presence of glycyrrhizin both in the pure DOPC membrane and in the membrane with cholesterol. This effect can be explained by the formation of hydrogen bonds between NF and GA in the middle of the bilayer.

Pharmacological Efficacy and Safety of Glycyrrhiza glabra in the Treatment of Respiratory Tract Infections.

Respiratory tract infections are underestimated because they are mild and disabling, but in clinical medicine, these are the most prevalent problems. According to the World Health Organization third-most comprehensive cause of death in the world till 2030 would be Chronic Obstructive Pulmonary Disease (COPD). Dominating viruses of respiratory infections are influenza, respiratory syncytial virus, rhinoviruses, and human coronaviruses. Antibiotics are mostly used to treat bacterial infections, and they do not effectively manage viral infections like sinusitis, sore throats, bronchitis, influenza, and common respiratory infections. Presently no medication is available only symptomatic interventions is an option in our hand. However, a lot of research is going on the vaccine and drugs-based approaches against respiratory viruses worldwide. Traditional medicines are getting the attraction to treat many diseases. It is vital to screen the medicinal plants to find the potential of new compounds for treatment against antiviral and antimicrobial activities. Glycyrrhiza glabra L. (Licorice) pharmacological actions modulate the immune system, inhibit virus growth, produce anti-inflammatory activity, and inactivate viruses. This comprehensive review mainly focuses on the role of licorice in managing respiratory infections caused by viruses and bacteria, including complications associated with its excess intake. There has been limited human research's exhibited licorice effectiveness in respiratory infections; therefore, there is a need for uncompromising and long-term research. This paper will be a valuable reference for biologists and physicians looking for a medication for respiratory infections. Glycyrrhiza glabra could open the door to novel agents in drug discovery and development.

Research Progress on the Antiviral Activity of Glycyrrhizin and its Derivatives in Liquorice.

Liquorice is a traditional medicine. Triterpenoids such as glycyrrhizin and glycyrrhetinic acid are the main active constituents of liquorice. Studies have revealed that these compounds exert inhibitory effects on several viruses, including SARS-CoV-2. The main mechanisms of action of these compounds include inhibition of virus replication, direct inactivation of viruses, inhibition of inflammation mediated by HMGB1/TLR4, inhibition of ß-chemokines, reduction in the binding of HMGB1 to DNA to weaken the activity of viruses, and inhibition of reactive oxygen species formation. We herein review the research progress on the antiviral effects of glycyrrhizin and its derivatives. In addition, we emphasise the significance of exploring unknown antiviral mechanisms, structural modifications, and drug combinations in future studies.