Review article: glycyrrhizin as a potential treatment for chronic hepatitis C

A systematic review and meta-analysis of efficacy and safety of compound glycyrrhizin combined with second-generation non-sedated antihistamine for the treatment of chronic urticaria

BACKGROUND

Chronic urticaria (CU) is a prevalent dermatologic disease that negatively affects life, current therapies remain suboptimal. Hence, there is an urgent need to identify effective and safe treatment.

OBJECTIVE

Assess the efficacy and safety of compound glycyrrhizin (CG) combined with second-generation nonsedated antihistamine for the treatment of CU.

METHODS

Nine databases were queried to screen RCTs related. Two reviewers independently assessed the risk of bias using Cochrane Collaboration. Primary objective was the total efficiency rate, while secondary was rate of recurrence, adverse events, and cure. Statistical analyses using Review Manager 5.4 and Stata17.

RESULTS

Twenty-four RCTs were identified. Significant differences were noted in rate of total efficiency (n = 2649, RR = 1.36, 95%CI:1.30-1.43, p < 0.00001), cure (n = 2649, RR = 1.54, 95%CI:1.42-1.66, p < 0.00001) and recurrence (n = 446, RR = 0.34, 95%CI:0.20-0.58, p < 0.00001) between the combination of CG with second-generation non-sedated antihistamine and antihistamine monotherapy. Contrastingly, adverse events rate (n = 2317, RR = 0.76, 95% CI:0.59-0.97, p = 0.03) was comparable between the two groups. Our results indicated that CG combined with second-generation non-sedated antihistamine could significantly mitigate the symptoms in CU compared with antihistamine monotherapy. No serious adverse events were reported.

CONCLUSIONS

CG combined with second-generation nonsedated antihistamine is effective for CU. Nevertheless, higher-quality studies are warranted to validate our results.

Non-alcoholic fatty liver disease and psoriasis: mechanisms of comorbidity and approaches to therapy

Psoriasis is a chronic immune-mediated skin disease of a multifactorial nature, characterized by accelerated proliferation of keratinocytes and impaired differentiation, an imbalance between pro-inflammatory and anti-inflammatory cytokines, with frequent involvement of the musculoskeletal system in the pathological process. The etiology of psoriasis is unknown, but several risk factors have been identified, including family history, smoking and obesity. The high prevalence of obesity, diseases of the cardiovascular system and digestive organs in patients with psoriasis allows us to consider it as an indicator of the patient’s metabolic disorders. In the structure of comorbidity of patients with psoriasis, special attention is drawn to non-alcoholic fatty liver disease (NAFLD), which occupies a leading position in the structure of the incidence of chronic diffuse liver diseases among the adult population in many countries of the world, including Russia. Patients with psoriasis are more often diagnosed with NAFLD, regardless of the presence of metabolic syndrome and other traditional risk factors. The presence of NAFLD is associated with more severe psoriasis and worse outcomes. On the other hand, a negative effect of psoriasis on the course of liver pathology has been noted. In this regard, it seems particularly relevant to study the etiological factors and pathogenetic links underlying this comorbidity, as potential targets for targeted therapy, which can improve the effectiveness of treatment for this cohort of patients. The purpose of this review publication is to summarize and systematize the available data on the prevalence of comorbidity of psoriasis and NAFLD in the population, the mechanisms of its formation and approaches to patient management.

A bibliometric review of Glycyrrhizae Radix et Rhizoma (licorice) research: Insights and future directions

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhizae Radix et Rhizoma, a Chinese herb known as licorice, is frequently incorporated in traditional Chinese medicine (TCM) formulations, due to its significant medicinal value and sweet taste. Despite licorice's merits, no systematic scientometric study has yet been conducted to analyze licorice research trends over the past 25 years.

AIM OF THE STUDY

We conducted this study with the aim to provide researchers with a comprehensive overview of research advances in the application of licorice as a TCM ingredient and to offer valuable insights to guide future endeavors in this research field.

METHODS

We selected licorice-related research papers published between 1997 and 2021 from the Web of Science Core Collection then conducted a scientometric analysis using VOSviewer and CiteSpace software tools.

RESULTS

A total of 4883 licorice-related publications, including 4511 research papers, 372 review papers, and their cited references, were included in the analysis. Most of these articles were authored by researchers in China (36.8%), including major contributors Wang Ying, Ye Min, and Zhang Yu. The Journal of Ethnopharmacology (impact factor = 5.4) hosted the greatest number of papers (145 articles). Keyword cluster analysis revealed three keyword categories indicating that current licorice research is focused on licorice quality control and identification of licorice active ingredients and associated pharmacological mechanisms.

CONCLUSION

This study provides a comprehensive overview of licorice-related research trends over the past 25 years as based on quantitative and qualitative analyses of published licorice-related articles. The results of this multi-level analysis of licorice research related to TCM formulations, chemical compositions, and pharmacological effects should provide valuable reference data and insights to guide future research endeavors in this field.

New Perspectives for Antihypertensive Sartans as Components of Co-crystals and Co-amorphous Solids with Improved Properties and Multipurpose Activity

Sartans (angiotensin II receptor blockers, ARBs), drugs used in the treatment of hypertension, play a principal role in addressing the global health challenge of hypertension. In the past three years, their potential use has expanded to include the possibility of their application in the treatment of COVID-19 and neurodegenerative diseases (80 clinical studies worldwide). However, their therapeutic efficacy is limited by their poor solubility and bioavailability, prompting the need for innovative approaches to improve their pharmaceutical properties. This review discusses methods of co-crystallization and co-amorphization of sartans with nonpolymeric, low molecular, and stabilizing co-formers, as a promising strategy to synthesize new multipurpose drugs with enhanced pharmaceutical properties. The solid-state forms have demonstrated the potential to address the poor solubility limitations of conventional sartan formulations and offer new opportunities to develop dual-active drugs with broader therapeutic applications. The review includes an in-depth analysis of the co-crystal and co-amorphous forms of sartans, including their properties, possible applications, and the impact of synthetic methods on their pharmacokinetic properties. By shedding light on the solid forms of sartans, this article provides valuable insights into their potential as improved drug formulations. Moreover, this review may serve as a valuable resource for designing similar solid forms of sartans and other drugs, fostering further advances in pharmaceutical research and drug development.

Implementation of Quality by Design Approaches for Development and Validation of Reverse-Phase High-Performance Liquid Chromatography Assay Method for Determination of Glycyrrhizin in Nanoformulation

Glycyrrhizin (GL) is the principal constituent of Glycyrrhiza glabra, having antiallergic, anticancer, anti-inflammatory, and antimicrobial action. The reverse-phase high-performance liquid chromatography (RP-HPLC) analytical method was used to quantitatively estimate GL in a nanoformulation and validated as per International Conference on Harmonization Q2 (R1) standards. A stationary phase of the C18-HL reversed-phase column and a mobile phase of acetonitrile and water were used for effective elution. The chromatographic conditions of RP-HPLC were optimized utilizing a quality-by-design approach to accomplish the required chromatographic separation of GL from its nanoformulation with minimal experimental runs. Optimized RP-HPLC conditions for the assay method consist of acetonitrile (41%) and water, pH 1.8, balanced with phosphoric acid (0.1%) as a mobile phase with a flow rate of 1 mL/min. The retention time was found at 7.25 min, and method validation confirmed its sensitivity, preciseness, accuracy, and robustness.

Glycyrrhizic acid enhances the anticancer activity of cisplatin in the human ovarian cancer cell line

This study aimed to investigate the effects of glycyrrhizic acid (GL) on the anticancer activity of cisplatin in A2780 ovarian cancer cells. Cultured A2780 cells were treated with different concentrations of GL and cisplatin individually and in combination. The MTT assay, flow cytometry, wound-healing, and clonogenic assay, were used to determine cell viability, apoptosis, migration, and colony formation, respectively. The effects on superoxide dismutase (SOD) activity were also evaluated. QPCR was used to study the effects of individual and combined treatments with GL and cisplatin on the expression levels of migration genes (MMP2 and MMP9), and some apoptosis pathway genes (caspase-3, -8, -9, and BCL2). A synergistic effect was observed between GL and cisplatin (CI < 1). Combination therapy was significantly more effective in reducing cell viability, suppressing migration and colony formation, inducing apoptosis, and altering gene expression compared to single therapies. GL significantly increased SOD activity. The relative expression of caspase -3, -8, and - 9 increased significantly, and the expression levels of MMP2 and MMP9 decreased significantly in the treated cells. Our results indicate that GL enhances the anticancer activity of cisplatin in the A2780 cell line. Therefore, the combination of GL and cisplatin can be proposed as a promising therapeutic strategy for ovarian cancer.

Use of complementary and alternative medicine in children affected by oncologic, neurologic and liver diseases: a narrative review

Complementary and alternative medicine (CAM) consist of a broad group of restorative resources often linked to existing local cultures and established health care systems and are also increasingly used in children with some serious illnesses. In this narrative review, we examine the epidemiology of the use, efficacy, and safety of complementary and alternative medicine in pediatric oncology, neurology, and hepatology. We searched for relevant articles published in Pubmed evaluating CAM use and its efficacy in safety in children affected by oncologic, neurologic and liver diseases. CAM is used to improve the success of conventional therapies, but also to alleviate the pain, discomfort, and suffering resulting from the diseases and their treatment, which are often associated with a significant burden of adverse effects. CAM use must be evaluated in children with neurological, oncological and liver diseases.

Nanofibers of Glycyrrhizin/Hydroxypropyl-β-Cyclodextrin Inclusion Complex: Enhanced Solubility Profile and Anti-inflammatory Effect of Glycyrrhizin

Despite having a wide range of therapeutic advantages, glycyrrhizin (GL) has few commercial applications due to its poor aqueous solubility. In this study, we combined the benefits of hydroxypropyl β-cyclodextrin (HP-βCD) supramolecular inclusion complexes and electrospun nanofibers to improve the solubility and therapeutic potential of GL. A molecular inclusion complex containing GL and HP-βCD was prepared by lyophilization at a 1:2 molar ratio. GL and hydroxypropyl β-cyclodextrin inclusion complexes were also incorporated into hyaluronic acid (HA) nanofibers. Prepared NF was analyzed for physical, chemical, thermal, and pharmaceutical properties. Additionally, a rat model of carrageenan-induced hind paw edema and macrophage cell lines was used to evaluate the anti-inflammatory activity of GL-HP-βCD NF. The DSC and XRD analyses clearly showed the amorphous state of GL in nanofibers. In comparison to pure GL, GL-HP-βCD NF displayed improved release (46.6 ± 2.16% in 5 min) and dissolution profiles (water dissolvability ≤ 6 s). Phase solubility results showed a four-fold increase in GL solubility in GL-HP-βCD NF. In vitro experiments on cell lines showed that inflammatory markers like IL-1β, TNF-α, and IL-6 were significantly lower in GL-HP-βCD NF compared to pure GL (p < 0.01 and p < 0.05). According to in vivo results, the prepared nanofiber exhibits a better anti-inflammatory effect than pure GL (63.4% inhibition vs 53.7% inhibition). The findings presented here suggested that GL-HP-βCD NF could serve as a useful strategy for improving the therapeutic effects of GL.

Glycyrrhizae Radix et Rhizoma: The popular occurrence of herbal medicine applied in classical prescriptions

Glycyrrhizae Radix et Rhizoma is a well-known herbal medicine with a wide range of pharmacological functions that has been used throughout Chinese history. This review presents a comprehensive introduction to this herb and its classical prescriptions. The article discusses the resources and distribution of species, methods of authentication and determination chemical composition, quality control of the original plants and herbal medicines, dosages use, common classical prescriptions, indications, and relevant mechanisms of the active content. Pharmacokinetic parameters, toxicity tests, clinical trials, and patent applications are discussed. The review will provide a good starting point for the research and development of classical prescriptions to develop herbal medicines for clinical use.

A Review of the Antiviral Activities of Glycyrrhizic Acid, Glycyrrhetinic Acid and Glycyrrhetinic Acid Monoglucuronide

Licorice, a natural medicine derived from the roots and rhizomes of Glycyrrhiza species, possesses a wide range of therapeutic applications, including antiviral properties. Glycyrrhizic acid (GL) and glycyrrhetinic acid (GA) are the most important active ingredients in licorice. Glycyrrhetinic acid 3-O-mono-β-d-glucuronide (GAMG) is the active metabolite of GL. GL and its metabolites have a wide range of antiviral activities against viruses, such as, the hepatitis virus, herpes virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and so on. Although their antiviral activity has been widely reported, the specific mechanism of action involving multiple links such as the virus itself, cells, and immunity are not clearly established. In this review, we will give an update on the role of GL and its metabolites as antiviral agents, and detail relevant evidence on the potential use and mechanisms of actions. Analyzing antivirals, their signaling, and the impacts of tissue and autoimmune protection may provide promising new therapeutic strategies.

Nutmeg Essential Oil, Red Clover, and Liquorice Extracts Microencapsulation Method Selection for the Release of Active Compounds from Gel Tablets of Different Bases

The current study presents the most suitable method for encapsulating nutmeg essential oil with liquorice and red clover. Two widely used methods, spray-drying and freeze-drying, were employed to find the most suitable for essential oil volatile compounds’ protection. Results showed that freeze-dried capsules (LM) had a higher yield (85.34%) compared to the exact formulation of spray-dried microcapsules (SDM)—45.12%. All the antioxidant and total phenolic compounds’ results obtained with the LM sample were significantly higher compared with SDM. LM microcapsules were incorporated in two different bases with no additional sugar (gelatin and pectin) for targeted release. Pectin tablets had firmer and harder texture properties, while gelatin tablets had a more elastic texture. There was a significant impact on texture changes caused by microcapsules. Microencapsulated essential oil with extracts can be used alone or in a gel base (pectin or gelatin, depending on user preferences). It could be an effective product to protect the active volatile compounds and regulate the release of active compounds and give a pleasant taste.

Antibacterial activity of 18β-glycyrrhetinic acid against Neisseria gonorrhoeae in vitro

Gonorrhea is the second most common sexually transmitted diseases worldwide. Chronic infection of Neisseria gonorrhoeae (N. gonorrhoeae) can lead to severe complications. Presently, N. gonorrhoeae has developed resistance to almost all antibiotics used for the treatment of gonorrhea. Thus, it's urgent to explore new approaches to treat gonorrhea. Presently, nontraditional treatment method as an alternative to antibiotic use is getting more and more attention. Here we demonstrated that 18β-glycyrrhetinic acid (GRA) exhibited robust antimicrobial activity against N. gonorrhoeae in vitro. GRA led to a significant decline in viable N. gonorrhoeae in a dose dependent manner compared with DMSO treatment (P < 0.001). Addition of GRA resulted in a significant reduction in viable bacteria within 2 h post-inoculation (P < 0.001). Minimum inhibitory concentrations (MICs) to GRA ranged from 3.9 to 62.5 μg/ml overall, with MIC50 and MIC90 values of 31.25 μg/ml and 62.5 μg/ml, respectively. There was no significant difference of MIC 50 and MIC90 between multi-drug resistant (MDR) strains and non-MDR strains. Minimum bactericidal concentration (MBC) ranges were 3.9-125 μg/ml, basically consistent with MIC values. GRA inhibited biofilm formation and diminished pre-formed biofilm. These data suggested that GRA could be a candidate for gonorrhea treatment.

Characterization of Triterpene Saponin Glycyrrhizin Transport by Glycyrrhiza glabra

Glycyrrhizin (GL), a triterpene compound produced by Glycyrrhiza species, is a crucial pharmacologically active component of crude drugs. In contrast to the biosynthesis of GL in plants, little is known about GL transport and accumulation in plants. The transport mechanism of GL was characterized using cultured cells of Glycyrrhiza glabra. Cultured cells of G. glabra efficiently incorporated exogenously supplied GL. Proton pump inhibitors, such as probenecid and niflumic acid, as well as a protonophore (carbonylcyanide m-chlorophenylhydrazone), markedly inhibited GL uptake by cultured cells, whereas vanadate exhibited a moderate inhibition. Furthermore, GL transport by G. glabra tonoplast vesicles is dependent not on a H+-electrochemical gradient but MgATP and is markedly inhibited by vanadate. These results suggest that GL uptake by cultured cells is mediated by a H+-symporter in the plasma membrane and an ATP-binding cassette transporter, which has high specificity for the aglycone structure of GL on the tonoplast.

An analysis of the efficacy and safety of compound glycyrrhizin injections in the treatment of drug-induced liver injury using a nationwide database

Background Drug-induced liver injury (DILI) refers to liver damage caused by drugs. DILI poses a significant challenge in the development of new drugs. The management of DILI mainly involves the withdrawal of the offending drug, and there is a lack of specific therapy. This study sought to evaluate the efficacy and safety of compound glycyrrhizin (CG) injections in DILI patients. Aim To evaluate the efficacy and safety of compound glycyrrhizin injections in DILI treatment. Methods The clinical data of DILI patients were collected from a nationwide DILI database. Patients were divided into two groups: the compound glycyrrhizin (CG) group who received CG injections, and the control group who received no treatment. The propensity score matching (PSM) method was applied to obtain an even distribution of characteristics between the two groups. The efficacy of the CG injections was assessed by the analysis of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels between the two groups. Results There were 152 patients in the compound glycyrrhizin group and 512 patients in the control group. The PSM method was used to acquire 152 matched pairs. The compound glycyrrhizin group had a significantly higher overall ALT and AST normalization rate than the control group (43.42% vs. 24.34%, p = 0.0004 and 63.82% vs. 38.82%, p ≤ .0001). There was no difference in the levels of renal and serum biochemical parameters between the two groups. Conclusions CG injections are effective in reducing ALT and AST levels in DILI patients, and their safety is comparable to the control group.

Study on antioxidant potential, immunological response, and inflammatory cytokines induction of glycyrrhizic acid (GA) in silver carp against vibriosis

Effect of dietary with 100, 200, and 300 mg kg^-1 glycyrrhizic acid (GA) on growth enhancer, blood physiology, digestive-antioxidant enzyme ability, innate-adaptive defense, and inflammatory cytokines induction was studied in silver carp, Hypophthalmichthys molitrix against vibriosis caused by Vibrio alginolyticus. Significant weight gain (WG), specific growth rate (SGR), and 100% survival rate (SR) was attained non-infected health (NiH) fish fed in control or all GA diets on 30, 45, and 60 days. Both NiH and V. alginolyticus challenged (VaC) fish treated with 200 mg GA diet significantly (P < 0.05) exhibited an enhancement in leucocytes value on 30, 45, and 60 days. Albumin (AB) or total proteins (TP) levels were significantly (P < 0.05) better in both groups fed 200 GA on 45 and 60 days. Malondialdehyde (MDA) and superoxide dismutase (SOD) activities were also substantial (P < 0.05) in both groups fed 200 mg GA on days 30, 45, and 60; whereas glutathione peroxidase (GPx) and catalase (CAT) activities were significantly (P < 0.05) better in both groups received 200 mg GA on days 45 and 60. Phagocytic (PC) and lysozyme (Lyz) activities significantly enhanced in both groups fed 200 or 300 mg GA on 45 and 60 days. Respiratory burst (RB), reactive oxygen species (ROS) and immunoglobulin (Ig) production significantly (P < 0.05) increased in both groups administered 200 or 300 mg GA. Growth hormone (GH) mRNA was up regulated in 200 mg GA trial on 45 days and in 200 or 300 mg GA treatments on 60 days. The IL-8 cytokine mRNA expression was up-regulated in both groups 200 and 300 mg GA on days 45 and 60, whereas TNF-α mRNA expression was increased in 200 mg GA. In addition, IL-10 cytokine mRNA expression was up regulated in 200 mg GA on 45 days whereas it was increased in both 200 mg and 300 mg GA trial on 60 days. The present study revealed that feeding fish 200 mg GA per kg diet demonstrated a better growth, digestive-antioxidant activity, innate-adaptive defense, and inflammatory cytokines induction than lower or higher dosage of GA in H. molitrix against V. alginolyticus.

Combination of natural antivirals and potent immune invigorators: A natural remedy to combat COVID-19

The flare-up in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that emerged in December 2019 in Wuhan, China, and spread expeditiously worldwide has become a health challenge globally. The rapid transmission, absence of anti-SARS-CoV-2 drugs, and inexistence of vaccine are further exacerbating the situation. Several drugs, including chloroquine, remdesivir, and favipiravir, are presently undergoing clinical investigation to further scrutinize their effectiveness and validity in the management of COVID-19. Natural products (NPs) in general, and plants constituents specifically, are unique sources for various effective and novel drugs. Immunostimulants, including vitamins, iron, zinc, chrysin, caffeic acid, and gallic acid, act as potent weapons against COVID-19 by reinvigorating the defensive mechanisms of the immune system. Immunity boosters prevent COVID-19 by stimulating the proliferation of T-cells, B-cells, and neutrophils, neutralizing the free radicals, inhibiting the immunosuppressive agents, and promoting cytokine production. Presently, antiviral therapy includes several lead compounds, such as baicalin, glycyrrhizin, theaflavin, and herbacetin, all of which seem to act against SARS-CoV-2 via particular targets, such as blocking virus entry, attachment to host cell receptor, inhibiting viral replication, and assembly and release.

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.

Exploring the Pivotal Immunomodulatory and Anti-Inflammatory Potentials of Glycyrrhizic and Glycyrrhetinic Acids

Licorice extract is a Chinese herbal medication most often used as a demulcent or elixir. The extract usually consists of many components but the key ingredients are glycyrrhizic (GL) and glycyrrhetinic acid (GA). GL and GA function as potent antioxidants, anti-inflammatory, antiviral, antitumor agents, and immuneregulators. GL and GA have potent activities against hepatitis A, B, and C viruses, human immunodeficiency virus type 1, vesicular stomatitis virus, herpes simplex virus, influenza A, severe acute respiratory syndrome-related coronavirus, respiratory syncytial virus, vaccinia virus, and arboviruses. Also, GA was observed to be of therapeutic valve in human enterovirus 71, which was recognized as the utmost regular virus responsible for hand, foot, and mouth disease. The anti-inflammatory mechanism of GL and GA is realized via cytokines like interferon-γ, tumor necrotizing factor-α, interleukin- (IL-) 1β, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, and IL-17. They also modulate anti-inflammatory mechanisms like intercellular cell adhesion molecule 1 and P-selectin, enzymes like inducible nitric oxide synthase (iNOS), and transcription factors such as nuclear factor-kappa B, signal transducer and activator of transcription- (STAT-) 3, and STAT-6. Furthermore, DCs treated with GL were capable of influencing T-cell differentiation toward Th1 subset. Moreover, GA is capable of blocking prostaglandin-E2 synthesis via blockade of cyclooxygenase- (COX-) 2 resulting in concurrent augmentation nitric oxide production through the enhancement of iNOS2 mRNA secretion in Leishmania-infected macrophages. GA is capable of inhibiting toll-like receptors as well as high-mobility group box 1.

Influence of Glycyrrhiza glabra Extract on Growth, Gene Expression of Gut Integrity, and Campylobacter jejuni Colonization in Broiler Chickens

Phytogenic feed additives have been gaining considerable interest due to their ability to improve gut health and thereby performance of broiler chickens. The impact of Glycyrrhiza glabra (licorice) extract (GE) on expression of genes coding for tight junction proteins and gut protection and Campylobacter jejuni colonization in broilers has not been discussed until now. Thus, the current study assessed the effective dose of GE for maximum growth in broiler chickens, clear-cut molecular mechanisms related to integrity and health of intestine, and controlling C. jejuni colonization. Over a 35-day feeding period, a total of 500 Ross broiler chicks were allocated to five groups; the first group was fed a control diet without GE and the second group to the fifth group were fed a control diet with GE (0.25, 0.5, 1, and 2 g/kg of diet); each group comprised 100 chicks with 10 replicates (10 birds/replicate). Birds fed GE had an improved body weight gain and feed conversion ratio. Furthermore, the highest body weight gain was observed in the group that received 1 g/kg of GE (P < 0.05). The expression of genes coding for tight junction proteins [occludin and junctional adhesion molecules (JAM)] was upregulated in all groups supplemented with GE. Moreover, birds fed 1 g/kg of GE exhibited the maximum gene expression of occludin and JAM [0.2 and 0.3 fold change, respectively (P < 0.05)]. In relation to enterocyte protective genes [glucagon-like peptide (GLP-2) and fatty acid-binding protein (FABP-6)], use of GE significantly upregulated expression of GLP-2 gene with 0.8 fold change in 2 g/kg of the GE supplemented group (P < 0.05) while the expression of FABP-6 gene was not affected by GE supplementation (P > 0.05). After challenge with C. jejuni, the expression of mucin (MUC-2) gene was upregulated and the inflammatory markers such as Toll-like receptors (TLR-4) and interleukin (IL-1β) were downregulated with increasing level of supplemented GE (P < 0.05). The mean log10 count of C. jejuni in cecal samples after 7 days post-infection by culture and real-time qPCR was decreased in groups fed GE in a dose-dependent manner (P < 0.05). In addition, the highest reduction of C. jejuni count in cecal samples by culture and real-time qPCR was observed in the group fed 2 g/kg of GE (2.58 and 2.28 log10 CFU/g, respectively). Results from this study suggested that G. glabra extract (1 g/kg) improved growth performance of broiler chickens, as well as influenced the maintenance of intestinal integrity and reduced C. jejuni shedding from infected birds.

Promising terpenes as SARS-CoV-2 spike receptor-binding domain (RBD) attachment inhibitors to the human ACE2 receptor: Integrated computational approach

The spike protein receptor binding domain (S-RBD) is a necessary corona-viral protein for binding and entry of coronaviruses (COVs) into the host cells. Hence, it has emerged as an attractive antiviral drug target. Therefore, present study was aimed to target severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S-RBD with novel bioactive compounds to retrieve potential candidates that could serve as anti-coronavirus disease 2019 (COVID-19) drugs. In this paper, computational approaches were employed, especially the structure-based virtual screening followed by molecular dynamics (MD) simulation as well as binding energy analysis for the computational identification of specific terpenes from the medicinal plants, which can block SARS-CoV-2 S-RBD binding to Human angiotensin-converting enzyme 2 (H-ACE2) and can act as potent anti-COVID-19 drugs after further advancements. The screening of focused terpenes inhibitors database composed of ~1000 compounds with reported therapeutic potential resulted in the identification of three candidate compounds, NPACT01552, NPACT01557 and NPACT00631. These three compounds established conserved interactions, which were further explored through all-atom MD simulations, free energy calculations, and a residual energy contribution estimated by MM-PB(GB)SA method. All these compounds showed stable conformation and interacted well with the hot-spot residues of SARS-CoV-2 S-RBD. Conclusively, the reported SARS-CoV-2 S-RBD specific terpenes could serve as seeds for developing potent anti-COVID-19 drugs. Importantly, the experimentally tested glycyrrhizin (NPACT00631) against SARS-CoV could be used further in the fast-track drug development process to help curb COVID-19.

Drug repurposing using computational methods to identify therapeutic options for COVID-19

PURPOSE

Recently, the world has been dealing with a new type of coronavirus called COVID-19 that in terms of symptoms is similar to the SARS coronavirus. Unfortunately, researchers could not find a registered therapy to treat the infection related to the virus yet. Regarding the fact that drug repurposing is a good strategy for epidemic viral infection, we applied the drug repurposing strategy using virtual screening to identify therapeutic options for COVID-19. For this purpose, five proteins of COVID-19 (3-chymotrypsin-like protease (3CLpro), Papain-Like protease (PLpro), cleavage site, HR1 and RBD in Spike protein) were selected as target proteins for drug repositioning.

METHODS

First, five proteins of COVID-19 were built by homology modeling. Then FDA-approved drugs (2471 drugs) were screened against cleavage site and RBD in Spike protein via virtual screening. One hundred and twenty-eight FDA-approved drugs with the most favorable free-binding energy were attached to the cleavage site and RBD in Spike protein. Of these 128 drugs, 18 drugs have either been used currently as antiviral or have been reported to possess antiviral effects. Virtual screening was then performed for the 18 selected drugs with ACE2, 3CLpro and PLpro and HR1 and TMPRSS2.

RESULTS

According to the results, glecaprevir, paritaprevir, simeprevir, ledipasvir, glycyrrhizic acid, TMC-310911, and hesperidin showed highly favorably free binding energies with all tested target proteins.

CONCLUSION

The above-mentioned drugs can be regarded as candidates to treat COVID-19 infections, but further study on the efficiency of these drugs is also necessary.

Rapid magnetic particles-based enzyme immunoassay for the quality control of Glycyrrhiza spp. based on glycyrrhizin content

Glycyrrhizin (GC) is a triterpenoid saponin isolated from the roots of Glycyrrhiza spp., a medicinal plant that is present in 70% of Kampo prescriptions. Since the GC content in Glycyrrhiza spp. affects its various pharmacological activities, Glycyrrhiza spp. is prescribed to contain at least 2% of GC in the Japanese pharmacopoeia, and its quality control based on GC content is required. In this study, a magnetic particles-based enzyme immunoassay (MPs-EIA) was developed using specific monoclonal antibody against GC (MAb 2H2) for the detection of GC in Glycyrrhiza spp. In this system, the immunoreaction time using primary and secondary antibodies was reduced by taking advantage of the wide surface area of magnetic particles (MPs) conjugated with GC by N,N'‑carbonyldiimidazole (CDI)-mediated method. Optimization of MPs-EIA revealed that total assay time (~2 h) was reduced to over half of that of conventional indirect competitive enzyme-linked immunosorbent assay (ELISA) (~5 h). In addition, the GC concentration was detectable within the range from 97.7 to 781 ng/mL, with a limit of detection of 71.4 ng/mL. A series of further validation analyses support the reliability and accuracy of the developed MPs-EIA for the detection of GC in Glycyrrhiza spp. Since the present MPs-EIA overcomes the disadvantage of ELISA in terms of rapidity, it provides a useful approach for the effective quality control of Glycyrrhiza spp., especially when handling multiple samples.

Risk Factors, Pathogenesis, and Strategies for Hepatocellular Carcinoma Prevention: Emphasis on Secondary Prevention and Its Translational Challenges

Hepatocellular carcinoma (HCC) is a leading cause of cancer-associated mortality globally. Given the limited therapeutic efficacy in advanced HCC, prevention of HCC carcinogenesis could serve as an effective strategy. Patients with chronic fibrosis due to viral or metabolic etiologies are at a high risk of developing HCC. Primary prevention seeks to eliminate cancer predisposing risk factors while tertiary prevention aims to prevent HCC recurrence. Secondary prevention targets patients with baseline chronic liver disease. Various epidemiological and experimental studies have identified candidates for secondary prevention-both etiology-specific and generic prevention strategies-including statins, aspirin, and anti-diabetic drugs. The introduction of multi-cell based omics analysis along with better characterization of the hepatic microenvironment will further facilitate the identification of targets for prevention. In this review, we will summarize HCC risk factors, pathogenesis, and discuss strategies of HCC prevention. We will focus on secondary prevention and also discuss current challenges in translating experimental work into clinical practice.

The Potential of Glycyrrhizinate in the Management of COVID-19: A Systematic Review of the Efficacy and Safety of Glycyrrhizin Preparations in the Treatment of SARS and MERS

The SARS-CoV-2 outbreak in 2019 highlighted the fact that no specific medications providing effective treatment have been identified and approved. We explored the possibilities for COVID-19 by systematically reviewing evidence on the efficacy and safety of glycyrrhizin preparations for SARS and MERS. Electronic databases were systematically searched from inception to February 2020 for eligible studies that evaluated the efficacy and safety of glycyrrhizin preparations for SARS and MERS. A quantitative analysis or descriptive analysis was applied. Five retrospective cohort studies were included, and NOS scores ranged from 5-7 points. The clinical symptoms of dry cough, chest distress and dyspnoea improved quickly, and elevated serum levels of aminotransferase decreased after compound glycyrrhizin treatment. The SARS-CoV antibody appeared earlier in the treated group than in the control group ([Formula: see text][Formula: see text]d). Compared to that with conventional medications, the average period from peak to 50% improvement of lesions, in terms of X-ray manifestations, was shorter with compound glycyrrhizin treatment ([Formula: see text]2.1[Formula: see text]d), and treatment reduced the dosage ([Formula: see text][Formula: see text]mg/d) and duration of the corticosteroids used, without other serious adverse reactions. Based on the available evidence regarding glycyrrhizin preparations for treating SARS and MERS, we infer that compound glycyrrhizin could be an optional therapeutic strategy for SARS-CoV-2 infections, especially those complicated with liver damage. Further research using well-designed randomized clinical trials (RCTs) is warranted to determine the dosage and duration of use of compound glycyrrhizin and to monitor its specific adverse effects.

Glycyrrhizic acid promotes neural repair by directly driving functional remyelination

Natural compounds are a rich source of effective candidate drugs for the treatment of neurological disorders. Glycyrrhizic acid (GA), the major water-soluble ingredient isolated from Glycyrrhiza glabra, is reported to show anti-inflammatory and immunomodulatory activities. However, its effect on CNS demyelinating disease is unclear. In this study, we showed that GA ameliorated the clinical disease severity of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), especially at the chronic stage of clinical EAE. Histological evaluation demonstrated that, in the prophylactic treatment regimen, GA significantly inhibited inflammatory demyelination in the CNS. During the chronic stage when myelin and axon damage has already occurred, GA induced oligodendrocyte progenitor cell (OPC) differentiation into mature oligodendrocytes, thus effectively accelerating remyelination. Evidence from the cuprizone-induced mouse model of de- and remyelination, ex vivo organotypic slice cultures, and in vitro OPC maturation experiments indicated that the observed efficacy of this compound resulted directly from enhanced remyelination rather than immune suppression. Furthermore, we found that GA promoted oligodendrocyte maturation through modulating GSK-3β signaling pathways. Our data led to the conclusion that GA could be used as a potential therapeutic candidate for the treatment of demyelinating diseases such as MS, which remains refractory to available treatments.

Glycyrrhizin: An old weapon against a novel coronavirus

Currently, over 100 countries are fighting against a common enemy, the severe acute respiratory syndrome coronavirus (SARS-CoV)-2, which causes COVID-19. This has created a demand for a substance whose effectiveness has already been demonstrated in a similar scenario. Glycyrrhizin (GZ) is a promising agent against SARS-CoV-2 as its antiviral activity against SARS-CoV has already been confirmed. It is worthwhile to extrapolate from its proven therapeutic effects as there is a high similarity in the structure and genome of SARS-CoV and SARS-CoV-2. There are many possible mechanisms through which GZ acts against viruses: increasing nitrous oxide production in macrophages, affecting transcription factors and cellular signalling pathways, directly altering the viral lipid-bilayer membrane, and binding to the ACE2 receptor. In this review, we discuss the possible use of GZ in the COVID-19 setting, where topical administration appears to be promising, with the nasal and oral cavity notably being the potent location in terms of viral load. The most recently published papers on the distribution of ACE2 in the human body and documented binding of GZ to this receptor, as well as its antiviral activity, suggest that GZ can be used as a therapeutic for COVID-19 and as a preventive agent against SARS-CoV-2.

Compound glycyrrhizin combined with antihistamines for chronic urticaria: A protocol for systematic review and meta analysis

BACKGROUND

To investigate the efficacy and safety of compound glycyrrhizin (CG) combined with antihistamines in the treatment of chronic urticaria (CU).

METHODS

We will use computers to search all databases including Medline, Embase, Pubmed, Web of Science and Cochrane Central Register of Controlled Trials and China's 4 databases: China National Knowledge Infrastructure Database, China Biomedical Literature Database, China Science Journal Database, and Wanfang Database. Find data from creation date to July 2020. In addition, we will manually search the list of medical journals as a supplement. The scope of the search included randomized controlled clinical studies related to CG combined with antihistamines for CU. The primary outcome is the disease activity control. Secondary outcomes include response rate, adverse events, and recurrence rates. The Cochrane RevMan V5.3 Deviation Assessment Tool will be used to assess bias assessment risk, data integration risk, meta-analysis risk, and subgroup analysis risk (if conditions are met). The average difference, standard mean difference, and binary data will be used to represent continuous results.

RESULTS

This study will comprehensively review the existing evidence on CG combined with antihistamines for CU.

CONCLUSION

This systematic review will provide a basis for judging the effectiveness and safety of CG combined with antihistamines in the treatment of CU.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42020156153.

18β-Glycyrrhetinic acid acts through hepatocyte nuclear factor 4 alpha to modulate lipid and carbohydrate metabolism

Hepatocyte nuclear factor 4 alpha (HNF4α) regulates the expression of essential genes involved in very-low-density lipoprotein (VLDL) homeostasis and gluconeogenesis.　18β-glycyrrhetinic acid (GA) is an active ingredient of Glycyrrhiza uralensis an herbal medicine used for treating liver aliments. In this study, we established that GA functions as a partial antagonist of HNF4α through HNF4α-driven reporter luciferase assay and co-immunoprecipitation experiments with co-activator PGC1α. By virtual docking and site-directed mutagenesis analysis, we confirmed that serine 190 and arginine 235 of HNF4α are both essential for GA to exert its antagonistic action on HNF4α. Importantly, GA suppressed the expression of HNF4α target genes such as apolipoprotein B (ApoB), microsomal triglyceride transfer protein (MTP) and phospholipase A₂ G12B (PLA2G12B) modulating hepatic VLDL secretion in mice fed on a high fat diet. In addition, GA also suppressed gluconeogenesis and ameliorated glucose intolerance via down-regulating the expression of HNF4α target genes glucose-6-phosphatase (G6pc) and phosphoenolpyruvate carboxykinase (Pepck). Furthermore, GA significantly lowered blood glucose and improved insulin resistance in db/db mice. In all, we established that GA acts as a partial HNF4α antagonist modulating lipid and carbohydrate metabolism.

Glycyrrhizin Protects γ-Irradiated Mice from Gut Bacteria-Associated Infectious Complications by Improving miR-222-Associated Gas5 RNA Reduction in Macrophages of the Bacterial Translocation Site

Gut bacteria-associated sepsis is a serious concern in patients with gastrointestinal acute radiation syndrome (GIARS). In our previous studies, gut bacteria-associated sepsis caused high mortality rates in mice exposed to 6-9 Gy of γ-rays. IL-12⁺CD38⁺ iNOS⁺ Mϕ (M1Mϕ) located in the bacterial translocation site (mesenteric lymph nodes [MLNs]) of unirradiated mice were characterized as host defense antibacterial effector cells. However, cells isolated from the MLNs of GIARS mice were mostly CCL1⁺IL-10⁺LIGHT⁺miR-27a⁺ Mϕ (M2bMϕ, inhibitor cells for the M1Mϕ polarization). Reduced long noncoding RNA Gas5 and increased miR-222 expression in MLN-Mϕ influenced by the irradiation were shown to be associated with M2bMϕ polarization. In this study, the mortality of mice exposed to 7 Gy of γ-rays (7 Gy GIARS mice) was completely controlled after the administration of glycyrrhizin (GL), a major active ingredient in licorice root (Glycyrrhiza glabra). Bacterial translocation and subsequent sepsis were minimal in 7 Gy GIARS mice treated with GL. Increased Gas5 RNA level and decreased miR-222 expression were shown in MLN-Mϕ isolated from 7 Gy GIARS mice treated with GL, and these macrophages did not display any properties of M2bMϕ. These results indicate that gut bacteria-associated sepsis in 7 Gy GIARS mice was controlled by the GL through the inhibition of M2bMϕ polarization at the bacteria translocation site. Expression of Ccl1, a gene required for M2bMϕ survival, is silenced in the MLNs of 7 Gy GIARS mice because of Gas5 RNA, which is increased in these cells after the suppression of miR-222 (a Gas5 RNA expression inhibitor) by the GL.

Desensitization to trimethoprim-sulfamethoxazole in a toxoplasmic encephalitis patient who was intolerant to conventional treatments

Toxoplasma gondii is an obligate intracellular protozoan that causes toxoplasmic encephalitis (TE) in immunocompromised patients. We describe a case of a 29-year-old Japanese man presenting with headache and vomiting. He had previously been diagnosed with human immunodeficiency virus infection. Magnetic resonance imaging identified some nodules in his brain. We suspected TE and began treatment successively with parenteral trimethoprim-sulfamethoxazole (TMP/SMX) plus clindamycin. After that, we switched to pyrimethamine plus sulfadiazine (PMT/SDZ) because these drugs are the first-line treatment for TE. Because the patient experienced nausea and vomiting, PMT/SDZ was replaced with TMP/SMX, atovaquone, and clindamycin. However, the patient could not tolerate them owing to their adverse reactions. Thus, we attempted oral desensitization to TMP/SMX to treat his TE. We began desensitization with 0.4/2 mg of TMP/SMX. The patient experienced morbilliform rash and elevated aminotransferase levels. Therefore, we administered a glycyrrhizin and an antihistamine and continued the last tolerable dose until these symptoms improved. After 37 days, we achieved desensitization to 160/800 mg of TMP/SMX, and the patient's symptoms improved. After using nested-polymerase chain reaction to identify T. gondii DNA in his frozen cerebrospinal fluid, which was collected at admission, his diagnosis was confirmed as TE. This might be the first case to attempt desensitization to TMP/SMX to treat TE.

HMGB1 mediates the development of tendinopathy due to mechanical overloading

Mechanical overloading is a major cause of tendinopathy, but the underlying pathogenesis of tendinopathy is unclear. Here we report that high mobility group box1 (HMGB1) is released to the tendon extracellular matrix and initiates an inflammatory cascade in response to mechanical overloading in a mouse model. Moreover, administration of glycyrrhizin (GL), a naturally occurring triterpene and a specific inhibitor of HMGB1, inhibits the tendon’s inflammatory reactions. Also, while prolonged mechanical overloading in the form of long-term intensive treadmill running induces Achilles tendinopathy in mice, administration of GL completely blocks the tendinopathy development. Additionally, mechanical overloading of tendon cells in vitro induces HMGB1 release to the extracellular milieu, thereby eliciting inflammatory and catabolic responses as marked by increased production of prostaglandin E₂ (PGE₂) and matrix metalloproteinase-3 (MMP-3) in tendon cells. Application of GL abolishes the cellular inflammatory/catabolic responses. Collectively, these findings point to HMGB1 as a key molecule that is responsible for the induction of tendinopathy due to mechanical overloading placed on the tendon.

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.

Glycyrrhizin protects against sodium iodate-induced RPE and retinal injury though activation of AKT and Nrf2/HO-1 pathway

Glycyrrhizin is a bioactive triterpenoid saponin extracted from a traditional Chinese medicinal herb, glycyrrhiza, and has been reported to protect the organs such as liver and heart from injuries. However, there is no report about the effects of glycyrrhizin on atrophic age‐related macular degeneration (AMD). This study investigated the effects of glycyrrhizin on retinal pigment epithelium (RPE) in vitro and retina of mice in vivo treated with sodium iodate (SI). Glycyrrhizin significantly inhibited SI‐induced reactive oxygen species (ROS), and decreased apoptosis of RPE in vitro. The underlying mechanisms included increased phosphorylation of Akt, and increased expression of nuclear factor erythroid 2‐related factor2 (Nrf‐2) and HO‐1, thereby protecting RPE from SI‐induced ROS and apoptosis. Furthermore, glycyrrhizin significantly decreased the apoptosis of retinal cells in vivo, resulting in the inhibition of thinning of retina, decreasing the number of drusen and improving the function of retina. These findings suggested that glycyrrhizin may be a potential candidate for the treatment of atrophic AMD in clinical practice.

18β-glycyrrhetyl-3-O-sulfate would be a causative agent of licorice-induced pseudoaldosteronism

Licorice-induced pseudoaldosteronism is a common adverse effect in traditional Japanese Kampo medicine, and 3-monoglucuronyl glycyrrhetinic acid (3MGA) was considered as a causative agent of it. Previously, we found 22α-hydroxy-18β-glycyrrhetyl-3-O-sulfate-30-glucuronide (1), one of the metabolites of glycyrrhizin (GL) in the urine of Eisai hyperbilirubinuria rats (EHBRs) treated with glycyrrhetinic acid (GA), and suggested that it is also a possible causative agent of pseudoaldosteronism. The discovery of 1 also suggested that there might be other metabolites of GA as causal candidates. In this study, we found 22α-hydroxy-18β-glycyrrhetyl-3-O-sulfate (2) and 18β-glycyrrhetyl-3-O-sulfate (3) in EHBRs’ urine. 2 and 3 more strongly inhibited rat type 2 11β-hydroxysteroid dehydrogenase than 1 did in vitro. When EHBRs were orally treated with GA, GA and 1–3 in plasma and 1–3 in urine were detected; the levels of 3MGA were quite low. 2 and 3 were shown to be the substrates of organic anion transporter (OAT) 1 and OAT3. In the plasma of a patient suffering from pseudoaldosteronism with rhabdomyolysis due to licorice, we found 8.6 µM of 3, 1.3 µM of GA, and 87 nM of 2, but 1, GL, and 3MGA were not detected. These findings suggest that 18β-glycyrrhetyl-3-O-sulfate (3) is an alternative causative agent of pseudoaldosteronism, rather than 3MGA and 1.

Antiproliferative and apoptotic activity of glycyrrhizinic acid in MCF-7 human breast cancer cells and evaluation of its effect on cell cycle, cell migration and m-TOR/PI3K/Akt signalling pathway

INTRODUCTION

Glycyrrhizinic acid is a natural product of pharmacological relevance and its anticancer activity against breast cancer cell lines has not been evaluated. Therefore the main purpose of the present study was to investigate the anticancer effects of glycyrrhizinic acid in MCF-7 human breast cancer cells.

MATERIAL AND METHODS

The MTT assay was used to evaluate the anticancer effects while a clonogenic assay was used to study its effects on colony formation tendency. Flow cytometry was used to study the effects on cell cycle phase distribution and apoptosis. Western blot assay was used to study changes in protein expression of the m-TOR/PI3K/Akt pathway.

RESULTS

The results indicated that glycyrrhizinic acid caused significant (p < 0.01). The growth inhibitory effects MCF-7 human breast cancer cells. The growth inhibitory effects of glycyrrhizinic acid exhibited concentration-dependent as well as time-dependent growth inhibitory trend. Different doses of glycyrrhizinic acid had a tendency to significantly (p < 0.01) inhibit the colony formation tendency of MCF-7 cells. As compared to the control group, glycyrrhizinic acid-treated cells showed a high percentage of apoptotic cells. Cells treated with a 10, 50 and 100 µM dose of glycyrrhizinic acid led to a 24.3%, 41.5% and 82.1% increase in the sub-G1 phase (apoptotic) cells. Glycyrrhizinic acid also led to significant (p < 0.01) inhibition of cell invasion along with downregulation of m-TOR/PI3K/Akt protein expression.

CONCLUSIONS

Glycyrrhizinic acid inhibited MCF-7 human breast cancer cell growth and therefore may prove essential lead molecule in the treatment of breast cancer.

Liquorice (Glycyrrhiza glabra): A phytochemical and pharmacological review

In the last years, consumers are paying much more attention to natural medicines and principles, mainly due to the general sense that natural compounds are safe. On the other hand, there is a growing demand by industry for plants used in traditional medicine that could be incorporated in foods, nutraceuticals, cosmetics, or even pharmaceuticals. Glycyrrhiza glabra Linn. belongs to the Fabaceae family and has been recognized since ancient times for its ethnopharmacological values. This plant contains different phytocompounds, such as glycyrrhizin, 18β-glycyrrhetinic acid, glabrin A and B, and isoflavones, that have demonstrated various pharmacological activities. Pharmacological experiments have demonstrated that different extracts and pure compounds from this species exhibit a broad range of biological properties, including antibacterial, anti-inflammatory, antiviral, antioxidant, and antidiabetic activities. A few toxicological studies have reported some concerns. This review addresses all those issues and focuses on the pharmacological activities reported for G. glabra. Therefore, an updated, critical, and extensive overview on the current knowledge of G. glabra composition and biological activities is provided here in order to explore its therapeutic potential and future challenges to be utilized for the formulation of new products that will contribute to human well-being.

Saponins enhance exon skipping of 2'-O-methyl phosphorothioate oligonucleotide in vitro and in vivo

BACKGROUND

Antisense oligonucleotide (ASO)-mediated exon skipping has been feasible and promising approach for treating Duchenne muscular dystrophy (DMD) in preclinical and clinical trials, but its therapeutic applications remain challenges due to inefficient delivery.

METHODS

We investigated a few Saponins for their potential to improve delivery performance of an antisense 2'-Omethyl phosphorothioate RNA (2'-OMePS) in muscle cells and in dystrophic mdx mice. This study was carried out by evaluating these Saponins' toxicity, cellular uptake, transduction efficiency in vitro, and local delivery in vivo for 2'-OMePS, as well as affinity study between Saponin and 2'-OMePS.

RESULTS

The results showed that these Saponins, especially Digitonin and Tomatine, enhance the delivery of 2'-OMePS with comparable efficiency to Lipofectamine 2k (LF-2k) -mediated delivery in vitro. Significant performance was further observed in mdx mice, up to 10-fold with the Digitonin as compared to 2'-OMePS alone. Cytotoxicity of the Digitonin and Glycyrrhizin was much lower than LF-2k in vitro and not clearly detected in vivo under the tested concentrations.

CONCLUSION

This study potentiates Saponins as delivery vehicle for 2'-OMePS in vivo for treating DMD or other diseases.

Isolation of a novel glycyrrhizin metabolite as a causal candidate compound for pseudoaldosteronism

Pseudoaldosteronism is a common adverse effect associated with traditional Japanese Kampo medicines. The pathogenesis is mainly caused by 3-monoglucuronyl glycyrrhetinic acid (3MGA), one of the metabolites of glycyrrhizin (GL) contained in licorice. We developed an anti-3MGA monoclonal antibody (MAb) and an ELISA system to easily detect 3MGA in the plasma and urine of the patients. However, we found that some metabolites of GL cross-reacted with this MAb. Mrp2-deficient Eisai Hyperbilirubinemia rats (EHBRs) were administered glycyrrhetinic acid (GA), and we isolated 22α-hydroxy-18β-glycyrrhetyl-3-O-sulfate-30-glucuronide (1) from the pooled urine with the guidance of positive immunostaining of eastern blot as the new metabolite of GL. The IC₅₀ of 1 for type 2 11β-hydroxysteroid dehydrogenase (11β-HSD2) was 2.0 µM. Similar plasma concentrations of 1 and GA were observed 12 h after oral administration of GA to EHBR. Compound 1 was eliminated via urine, whereas GA was not. In Sprague–Dawley (SD) rats orally treated with GA, compound 1 was absent from both the plasma and the urine. Compound 1 was actively transported into cells via OAT1 and OAT3, whereas GA was not. Compound 1, when produced in Mrp2-deficiency, represents a potential causative agent of pseudoaldosteronism, and might be used as a biomarker to prevent the adverse effect.

Phytocompounds modulating Aquaporins: Clinical benefits are anticipated

A series of plant-derived bioactive compounds belonging to the class of polyphenols, terpenes and capsaicinoids, interact with important pathophysiological pathways at a molecular, cellular and systemic level. Mechanisms of action include altering cell growth and differentiation, apoptosis, autophagy, inflammation, redox balance and metabolic and energy homeostasis. These effects might also involve the expression and function of Aquaporins (AQPs), a family of membrane channel proteins, involved in several body functions. The ultimate translational beneficial effect of such phytocompounds on AQPs in health and disease is a matter of intensive research. Results might provide novel therapeutic approaches to a number of human diseases. Here, we give an updated overview of this fast growing and promising field, discussing a number of phytocompounds and their action on AQPs and related potential clinical achievements.

Inhibition of Homophilic Interactions and Ligand Binding of the Receptor for Advanced Glycation End Products by Heparin and Heparin-Related Carbohydrate Structures

Background: Heparin and heparin-related sulphated carbohydrates inhibit ligand binding of the receptor for advanced glycation end products (RAGE). Here, we have studied the ability of heparin to inhibit homophilic interactions of RAGE in living cells and studied how heparin related structures interfere with RAGE⁻ligand interactions. Methods: Homophilic interactions of RAGE were studied with bead aggregation and living cell protein-fragment complementation assays. Ligand binding was analyzed with microwell binding and chromatographic assays. Cell surface advanced glycation end product binding to RAGE was studied using PC3 cell adhesion assay. Results: Homophilic binding of RAGE was mediated by V₁- and modulated by C₂-domain in bead aggregation assay. Dimerisation of RAGE on the living cell surface was inhibited by heparin. Sulphated K5 carbohydrate fragments inhibited RAGE binding to amyloid β-peptide and HMGB1. The inhibition was dependent on the level of sulfation and the length of the carbohydrate backbone. α-d-Glucopyranosiduronic acid (glycyrrhizin) inhibited RAGE binding to advanced glycation end products in PC3 cell adhesion and protein binding assays. Further, glycyrrhizin inhibited HMGB1 and HMGB1 A-box binding to heparin. Conclusions: Our results show that K5 polysaccharides and glycyrrhizin are promising candidates for RAGE targeting drug development.

Protective effects of compound ammonium glycyrrhizin, L‑arginine, silymarin and glucurolactone against liver damage induced by ochratoxin A in primary chicken hepatocytes

Ochratoxin A (OTA) is a mycotoxin that is produced by fungi in improperly stored food and animal feed. It exhibits nephrotoxic, hepatotoxic, embryotoxic, teratogenic, neurotoxic, immunotoxic and carcinogenic effects in laboratory and farm animals. In the present study, the hepatotoxicity of OPA was investigated in chicken primary hepatocytes. On this basis, the cytoprotective effects of compound ammonium glycyrrhizin (CAG), L‑arginine (L‑Arg), silymarin (Sil) and glucurolactone (GA) were investigated in vitro. Hepatocytes were treated with OTA, which resulted in a significant decrease in cell viability and increases in serum aspartate transaminase and alanine transaminase activities, as determined by an MTT assay and commercial kits, respectively. Furthermore, following OTA treatment, the levels of hepatic antioxidants, such as superoxide dismutase and glutathione, were decreased, and the lipid peroxidation product malondialdehyde was increased, compared with the control group. However, pretreatment with CAG, L‑Arg, Sil and GA significantly ameliorated these alterations and Sil exerted the optimum hepatoprotective effect. The apoptotic rates were measured by flow cytometry and the results revealed that OTA increased cell apoptosis. The four types of hepatoprotective compounds employed in the present study decreased the apoptosis rate and significantly reversed OTA‑induced increases in the mRNA expression levels of caspase‑3, which was determined by reverse transcription‑quantitative polymerase chain reaction. Furthermore, B‑cell lymphoma‑2 (Bcl‑2) mRNA expression was increased in OTA‑treated cells when pretreated with CAG, L‑Arg, Sil and GA. However, no alterations in the mRNA expression of Bcl‑2‑associated X were observed in the L‑Arg and GA groups, compared with the OTA‑only group. These results indicate that OTA may exhibit hepatotoxicity in chickens and that CAG, L‑Arg, Sil and GA may protect the liver against this via anti‑oxidative and antiapoptosis mechanisms. In addition, CAG and GA are likely to mediate their effects through the mitochondrion‑dependent apoptosis pathway; however, the exact hepatoprotective mechanism of L‑Arg and GA require further investigation. Therefore, CAG, L‑Arg, Sil and GA are potential candidates for the prevention and treatment of chicken liver injury.

Saponins as Natural Adjuvant for Antisense Morpholino Oligonucleotides Delivery In Vitro and in mdx Mice

Antisense oligonucleotide (AON) therapy for Duchenne muscular dystrophy has drawn great attention in preclinical and clinical trials, but its therapeutic applications are still limited due to inefficient delivery. In this study, we investigated a few saponins for their potential to improve delivery performance of an antisense phosphorodiamidate morpholino oligomer (PMO) both in vitro and in vivo. The results showed that these saponins, especially digitonin and tomatine, improve the delivery efficiency of PMO comparable to Endo-Porter-mediated PMO delivery in vitro. The significant enhancement of PMO targeting to dystrophin exon 23 delivery was further observed in mdx mice up to 7-fold with the digitonin as compared to PMO alone. Cytotoxicity of the digitonin and glycyrrhizin was lower than Endo-Porter in vitro and not clearly detected in vivo under the tested concentrations. These results demonstrate that optimization of saponins in molecular size and composition are key factors to achieve enhanced PMO exon-skipping efficiency. The higher efficiency and lower toxicity endow saponins as gene/AON delivery enhancing agents for treating muscular dystrophy or other diseases.

Effects of 18β-Glycyrrhetinic Acid on Fungal Protease-Induced Airway Inflammatory Responses

Airway epithelial cells secrete diverse inflammatory mediators in response to various stimuli. Thus, early regulation of immune responses in the airway epithelium is likely critical for the control of chronic inflammatory diseases. The purpose of the present study was to evaluate the effects of 18β-glycyrrhetinic acid (GA) on inflammatory responses generated in response to a fungal protease allergen that induces epithelial damage. To understand the underlying mechanisms, we also investigated the inhibitory effects of GA on the production of mitochondrial reactive oxygen species (ROS) in the human bronchial epithelial cell line BEAS2B. In this study, GA treatment reduced cytokine production and the human neutrophil cell line HL60 migration through decreased mitochondrial ROS production. In addition, GA significantly reduced inflammatory cell infiltration and cytokine levels in the bronchoalveolar lavage (BAL) fluid of fungal allergen-administered mice. Inhibitory effects of GA are dependent on the mitochondrial ROS/MAPK axis. Moreover, the effect of GA on the regulation of mitochondrial ROS depends on the expression of uncoupling protein-2 (UCP-2). Taken together, GA might represent a potential therapeutic agent for blocking inflammatory responses in airways.

Aquaporins as Targets of Dietary Bioactive Phytocompounds

Plant-derived bioactive compounds have protective role for plants but may also modulate several physiological processes of plant consumers. In the last years, a wide spectrum of phytochemicals have been found to be beneficial to health interacting with molecular signaling pathways underlying critical functions such as cell growth and differentiation, apoptosis, autophagy, inflammation, redox balance, cell volume regulation, metabolic homeostasis, and energy balance. Hence, a large number of biologically active phytocompounds of foods have been isolated, characterized, and eventually modified representing a natural source of novel molecules to prevent, delay or cure several human diseases. Aquaporins (AQPs), a family of membrane channel proteins involved in many body functions, are emerging among the targets of bioactive phytochemicals in imparting their beneficial actions. Here, we provide a comprehensive review of this fast growing topic focusing especially on what it is known on the modulatory effects played by several edible plant and herbal compounds on AQPs, both in health and disease. Phytochemical modulation of AQP expression may provide new medical treatment options to improve the prognosis of several diseases.

Glycyrrhizic acid prevents ultraviolet-B-induced photodamage: a role for mitogen-activated protein kinases, nuclear factor kappa B and mitochondrial apoptotic pathway

Glycyrrhizic acid (GA), a natural triterpene, has received attention as an agent that has protective effects against chronic diseases including ultraviolet UV-B-induced skin photodamage. However, the mechanism of its protective effect remains elusive. Here, we used an immortalized human keratinocyte cell line (HaCaT) and a small animal model (BALB/c mice), to investigate the protective effects of GA against UV-B-induced oxidative damage, and additionally, delineated the molecular mechanisms involved in the UV-B-mediated inflammatory and apoptotic response. In the HaCaT cells, GA inhibited the UV-B-mediated increase in intracellular reactive oxygen species (ROS) and down-regulated the release of pro-inflammatory cytokines interleukin (IL)-1α, -1β and -6, tumor necrosis factor (TNF)-α and prostaglandin E2 (PGE2). GA inhibited UV-B-mediated activation of p38 and JNK MAP kinases, COX-2 expression and nuclear translocation of NF-κB. Furthermore, GA inhibited UV-B-mediated apoptosis by attenuating translocation of Bax from the cytosol to mitochondria, thus preserving mitochondrial integrity. GA-treated HaCaT cells also exhibited elevated antiapoptotic Bcl-2 protein, concomitant with reduced caspase-3 cleavage and decreased PARP-1 protein. In BALB/c mice, topical application of GA on dorsal skin exposed to UV-B irradiation protected against epidermal hyperplasia, lymphocyte infiltration and expression of several inflammatory proteins, p38, JNK, COX-2, NF-κB and ICAM-1. Based on the above findings, we conclude that GA protects against UV-B-mediated photodamage by inhibiting the signalling cascades triggered by oxidative stress, including MAPK/NF-κB activation, as well as apoptosis. Thus, GA has strong potential to be used as a therapeutic/cosmeceutical agent against photodamage.

Preventive Effect of α-Tocopherol and Glycyrrhizin against Platelet-Neutrophil Complex Formation Induced by Hemodialysis Membranes

Background

The intradialytic activation of leukocytes is a major cause of hemodialysis (HD)-associated complications. Contact between blood and HD membranes frequently induces the formation of microaggregates composed of activated platelets and leukocytes, causing leukocyte activation that includes the generation of reactive oxygen species (ROS). This complex formation is mediated primarily by the interaction between P-selectin on activated platelets and its counter-ligands on leukocytes.

Objective

We examined the preventive effects of α-tocopherol and glycyrrhizin in vitro against platelet-neutrophil microaggregate formation and neutrophil ROS production induced by HD membranes.

Methods and Results

Microaggregate formation induced by the incubation of heparinized whole blood with polysulfone (PS) HD membranes was effectively inhibited by α-tocopherol and glycyrrhizin. α-Tocopherol, but not glycyrrhizin, was found to inhibit PS membrane-induced P-selectin expression on the platelet surface; however, glycyrrhizin did inhibit both the formation of neutrophil-platelet microaggregates induced by adenosine diphosphate (ADP) and the adhesion of HL60 leukemic cells to P-selectin-expressing Chinese hamster ovary (CHO) cells, suggesting that glycyrrhizin acts as a competitive inhibitor of P-selectin-mediated cell adhesion. Finally, these compounds almost completely abrogated PS membrane-induced and platelet-dependent ROS production by neutrophils.

Conclusions

These results suggest that α-tocopherol and glycyrrhizin may function as preventive agents of HD-associated leukocyte activation though the modulation of platelet-leukocyte interaction.