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

18β-glycyrrhetinic acid inhibits rotavirus replication in culture

BACKGROUND

Glycyrrhizin (GA) and primary metabolite 18β-glycyrrhetinic acid (GRA) are pharmacologically active components of the medicinal licorice root, and both have been shown to have antiviral and immunomodulatory properties. Although these properties are well established, the mechanisms of action are not completely understood. In this study, GA and GRA were tested for the ability to inhibit rotavirus replication in cell culture, toward a long term goal of discovering natural compounds that may complement existing vaccines.

METHODS

Epithelial cells were treated with GA or GRA various times pre- or post-infection and virus yields were measured by immunofluorescent focus assay. Levels of viral proteins VP2, VP6, and NSP2 in GRA treated cells were measured by immunoblot to determine if there was an effect of GRA treatment on the accumulation of viral protein.

RESULTS

GRA treatment reduced rotavirus yields by 99% when added to infected cultures post-- virus adsorption, whereas virus yields in GA treated cultures were similar to mock treated controls. Time of addition experiments indicated that GRA-mediated replication inhibition likely occurs at a step or steps subsequent to virus entry. The amounts of VP2, VP6 and NSP2 were substantially reduced when GRA was added to cultures up to two hours post-entry.

CONCLUSIONS

GRA, but not GA, has significant antiviral activity against rotavirus replication in vitro, and studies to determine whether GRA attenuates rotavirus replication in vivo are underway.

3-Monoglucuronyl-glycyrrhretinic acid is a substrate of organic anion transporters expressed in tubular epithelial cells and plays important roles in licorice-induced pseudoaldosteronism by inhibiting 11β-hydroxysteroid dehydrogenase 2

Licorice (glycyrrhiza root) has been used as a herbal medicine worldwide with its main active constituent being glycyrrhizin (GL). Licorice sometimes causes adverse effects such as inducing pseudoaldosteronism by inhibiting type 2 11β-hydroxysteroid dehydrogenase (11β-HSD2) caused by glycyrrhetinic acid (GA), a major metabolite of GL. In this study we compared the inhibitory effects of GA, GL, and 3-monoglucuronyl-glycyrrhetinic acid (3MGA), another metabolite of GL, on 11β-HSD2 activity by using microsomes and rat kidney tissue slices. GA, 3MGA, and GL inhibited 11β-HSD2 in rat kidney microsomes, with IC(50) values of 0.32, 0.26, and 2.2 μM, respectively. However, the inhibitory activity of these compounds was reduced markedly, in the slices, in a medium containing 5% bovine serum albumin. Assays using human embryonic kidney 293 cells with transient transformation in transporter genes showed that 3MGA is a substrate of human organic anion transporter (OAT) 1, human OAT3, and human organic anion-transporting peptide 4C1, whereas GA is not. When GA (100 mg/kg/day) was administered orally for 16 days to Eisai hyperbilirubinemic rats, plasma concentrations and urinary excretion of 3MGA were significantly higher, whereas the activity of 11β-HSD2 in kidney microsomes was significantly lower compared with Sprague Dawley rats. These results suggest that 3MGA is actively transported into tubules through OATs, resulting in the inhibition of 11β-HSD2. Because the plasma level of 3MGA depends on the function of hepatic transporters, monitoring 3MGA levels in plasma or urine may be useful for preventing pseudoaldosteronism when licorice or GL is prescribed to patients.

18α-Glycyrrhizin induces apoptosis and suppresses activation of rat hepatic stellate cells

Background

To investigate the potential mechanisms underlying the protective effects of 18α Glycyrrhizin (GL) on rat hepatic stellate cells (HSCs) and hepatocytes in vivo and in vitro.

Material/Methods

Sprague-Dawley (SD) rats were randomly divided into 5 groups: normal control group, liver fibrosis group, high-dose 18α GL group (25 mg/kg/d), intermediate-dose 18α GL group (12.5 mg/kg/d) and low-dose 18α GL group (6.25 mg/kg/d). The rat liver fibrosis model was induced by carbon tetrachloride (CCl4). The expressions of α-smooth muscle actin (αSMA) and NF-κB were determined by real-time PCR and immunohistochemistry.

Results

18αGL dose-dependently inhibited the CCl4-induced liver fibrosis. There were significant differences in the mRNA and protein expressions of αSMA between the fibrosis group and 18α-GL treatment groups, suggesting that 18α GL can suppress the proliferation and activation of HSCs. Few HSCs were apoptotic in the portal area and fibrous septum in the liver fibrosis group. However, the double-color staining of a-SMA and TUNEL showed that 18α-GL treatment groups increased HSC apoptosis. NF-κB was mainly found in the nucleus in the fibrosis group, while cytoplasmic expression of NF-κB was noted in the 18αGL groups. In the in vitro experiments, 18α GL promoted the proliferation of hepatocytes, but inhibited that of HSCs. HSCs were arrested in the G2/M phase following 18α GL treatment and were largely apoptotic.

Conclusions

18α-GL can suppress the activation of HSCs and induce the apoptosis of HSCs by blocking the translocation of NF-κB into the nucleus, which plays an important role in the protective effect of 18α-GL on liver fibrosis.

Evaluation of the immunity activity of glycyrrhizin in AR mice

In this study, we evaluated effect of glycyrrhizin on immunity function in allergic rhinitis (AR) mice. The AR mice model were induced by dripping ovalbumin in physiological saline (2 mg mL⁻¹, 10 μL) into the bilateral nasal cavities using a micropipette. After the AR model was induced, mice were randomly divided into six groups: the normal control, model, lycopene 20 mg kg⁻¹ (as positive control drug) group, and glycyrrhizin 10, 20, 30 mg kg⁻¹ groups. After the sensitization day 14, lycopene (20 mg/kg BW) and glycyrrhizin (10, 20 and 30 mg/kg BW) were given orally for 20 days once a day. Mice in the normal control and model groups were given saline orally once a day for 20 days. Results showed that glycyrrhizin treatment could dose-dependently significantly reduce blood immunoglobulin E (IgE), interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-6 (IL-6), nitrous oxide (NO), tumor necrosis factor-alpha (TNF-α) levels and nitrous oxide synthase (NOS) activity and enhance blood immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), interleukin-2 (IL-2) and interleukin-12 (IL-12) levels in AR mice. Furthermore, glycyrrhizin treatment could dose-dependently significantly enhance acetylcholinesterase (AchE) activity and reduce substance P (SP) level in peripheral blood and nasal mucosa of AR mice. We conclude that glycyrrhizin can improve immunity function in AR mice, suggesting a potential drug for the prevention and therapy of AR.

Efficacy of intravenous glycyrrhizin in the early stage of acute onset autoimmune hepatitis

BACKGROUND

Acute onset autoimmune hepatitis (AIH) shows acute presentation like acute hepatitis and does not have typical clinicopathological features of AIH. There is no gold standard for making the diagnosis. Therefore, losing the timing of starting immunosuppressive therapy, some of the cases develop into severe or fulminant form and have poor prognosis.

AIMS

Our aim was to elucidate the efficacy of intravenous glycyrrhizin in decreasing alanine aminotransferase (ALT) level in the early stage of acute onset AIH.

METHODS

Thirty-one patients were defined as acute onset AIH based on our uniform criteria, and were enrolled in this study. We prospectively treated 17 patients with sufficient doses (100 ml/day) of intravenous glycyrrhizin (SNMC) at an early stage (SNMC group), and treated 14 patients of severe disease with intravenous glycyrrhizin and corticosteroids (CS) (SNMC + CS group). We examined their clinical and biochemical features and treatment responses.

RESULTS

The ALT level could be controlled at an early stage using SNMC with no significant difference compared with SNMC + CS, and responsiveness to the therapy was determined by the disease severity at the time of starting therapy rather than the time duration from onset to therapy. Recovery rate was higher in the SNMC group than in the SNMC + CS group (P = 0.035).

CONCLUSIONS

The early introduction of sufficient doses of SNMC might prevent disease progression in patients with acute onset AIH. SNMC can be used safely and be useful for patients with difficult-to-diagnose acute liver disease as an 'initial' treatment tool to improve liver inflammation before starting disease-specific treatments.

Interaction of glycyrrhizin and glycyrrhetinic acid with DNA

Glycyrrhizin (GL), a molecule of glycyrrhetinic acid (GA), is an aqueous extract from licorice root. These compounds are well known for their anti-inflammatory, hepatocarcinogenesis, antiviral, and interferon-inducing activities. This study is the first attempt to investigate the binding of GL and GA with DNA. The effect of ligand complexation on DNA aggregation and condensation was investigated in aqueous solution at physiological conditions, using constant DNA concentration (6.25 mM) and various ligands/polynucleotide (phosphate) ratios of 1/240, 1/120, 1/80, 1/40, 1/20, 1/10, 1/5, 1/2, and 1/1. Fourier transform infrared and ultraviolet (UV)-visible spectroscopic methods were used to determine the ligand binding modes, the binding constants, and the stability of ligand-DNA complexes in aqueous solution. Spectroscopic evidence showed that GL and GA bind DNA via major and minor grooves as well as the backbone phosphate group with overall binding constants of K(GL-DNA)=5.7×10(3) M(-1), K(GA-DNA)=5.1×10(3) M(-1). The affinity of ligand-DNA binding is in the order of GL>GA. DNA remained in the B-family structure, whereas biopolymer aggregation occurred at high triterpenoid concentrations.

Isolation of phlorotannins from Eisenia bicyclis and their hepatoprotective effect against oxidative stress induced by tert-butyl hyperoxide

Eisenia bicyclis (Kjellman) Setchell is a common brown alga that inhabits the middle Pacific coast around Korea and Japan. In this study, the ethanol extract and its serial solvent fractions were prepared from fresh E. bicyclis, and their hepatoprotective effects were investigated against hepatotoxicity in tert-butyl hyperoxide(t-BHP)-injured HepG2 cells. When these samples were used at a dose of 10-40 μg/mL⁻¹, they significantly protected the t-BHP-induced cell death in HepG2 cells. Among fractions, ethyl acetate fraction (EF) and n-butanol extract (BF) exhibited potent hepatoprotective activities (62.60% for EF and 64.86% for BF) in t-BHP-injured HepG2 cells at a concentration of 10 μg/mL⁻¹. To find the potential factors for this activity, the samples were characterized on total phenolics, chlorophylls, carotenoids, and radical scavenging activity. Among them, EF showed the highest content of total phenolics and the strongest antioxidant activity both in on- and offline assays. Five phlorotannin compounds, oligomers of phloroglucinol, were isolated chromatographically from this fraction and structurally identified by (1)H-NMR and liquid chromatography-electrospray ionization-mass spectrometry analyses as eckol(1), 6,6'-bieckol(2), 8,8'-bieckol(3), dieckol(4), and phlorofucofuroeckol A(5). Compound 5 among five purified compounds showed the strongest protective activity (45.54%) at a concentration of 10 μM. At the high dose (40 μM), the protective activities of three compounds (compound 2, 4, and 5) were higher than that of quercetin treated with 10 μM concentration. Therefore, we can speculate that they can be developed as potential candidates for natural hepatoprotective agents.

Effects of Toll-like receptor signals in T-cell neoplasms

T-cell neoplasms have poor prognosis and few effective therapeutic options. Therefore, identification of factors in T-cell leukemia/lymphoma that are associated with cancer progression may represent novel therapeutic targets. Recent studies have highlighted a previously unappreciated role for the expression of Toll-like receptors (TLRs) on T cells and their effects on cell survival and proliferation. TLRs can bind exogenous molecules derived from pathogens as well as endogenous self-ligands released from damaged cells. Recent reports demonstrate that TLR engagement on primary mouse or human T cells enhances proliferation and/or cell survival. The mechanisms by which TLR stimulation on T cells influences these parameters and the different T-cell subsets that are affected by TLR stimulation are currently under investigation. Furthermore, neither the biological importance of stimulating TLRs on neoplastic T cells nor the prevalence of TLR expression in T-cell malignancies have yet to be characterized. Based on published reports and compelling preliminary data, we propose that the activation of the TLR-MyD88 signaling pathway in neoplastic T cells contributes to disease progression by reducing cell death and enhancing cell division. In this article, we present both theoretical arguments and experimental data in support of this hypothesis.

Molecular cloning and characterization of GuHMGR, an HMG-CoA reductase gene from liquorice (Glycyrrhiza uralensis)

A full length cDNA encoding HMGR (designated as GuHMGR) was isolated from liquorice (Glycyrrhiza uralensis) based on degenerated PCR and genome walking. The full length cDNA of GuHMGR was 2330 bp with a 1518-bp open reading frame (ORF) encoding a 505-aa polypeptide. Bioinformatics analysis indicated that there were two trans-membrane domains in GuHMGR. A molecular model of tertiary structure showed that GuHMGR is a novel HMGR with a similar spatial structure to other plant HMGRs. The deduced polypeptide of GuHMGR has an isoelectric point (pI) of 6.41 and a calculated molecular weight of about 54.7 kDa. Sequence comparison and phylogenetic tree analysis showed that GuHMGR had the highest homology with HMGRs from Pisum sativum and Medicago truncatula, indicating that GuHMGR belongs to the plant HMGR group. Expression analysis showed the similar amount of transcript level of GuHMGR in roots and leaves, suggesting that this gene was expressed constitutively in plants. Therefore, this novel HMGR gene would possibly provide a new strategy for studying the glycyrrhizin metabolism at the molecular level in the future.

Efficacy and safety in sitagliptin therapy for diabetes complicated by chronic liver disease caused by hepatitis C virus

AIM

  Diabetes is present in patients with chronic liver disease caused by hepatitis C virus (HCV). The aim of this case-control study is to assess the efficacy and safety of dipeptidyl peptidase-4 inhibitor (sitagliptin) for type 2 diabetes mellitus (T2DM) with chronic liver disease caused by HCV.

METHODS

  Sixteen HCV positive patients with T2DM treated by sitagliptin were retrospectively enrolled. These patients were given sitagliptin between December 2009 and January 2010. Another 16 HCV patients with T2DM treated only with diet and excise for 48 weeks were selected as the control group. Serum levels of fasting plasma glucose (FPG), hemoglobin A1C (HbA1C), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured before and 12, 24, 36 and 48 weeks after the initiation of treatment.

RESULTS

  In the sitagliptin group, the average HbA1C level decreased approximately 0.8% at 48 weeks after the initiation of sitagliptin. Next, the average FPG level decreased approximately 20 mg/dL during follow up after the initiation of sitagliptin. All the patients were able to take sitagliptin of 50 mg/day without reduction because of sitagliptin-related side-effects. On the other hand, in the control group, the average HbA1C and FPG level did not change with statistical significance during follow up of 48 weeks. Regarding aminotransferase, there were no significant changes of average AST and ALT level during follow up of 48 weeks in both the sitagliptin group and control group.

CONCLUSION

  Our results indicate that sitagliptin is effective and safe for the treatment of T2DM complicated with HCV positive chronic liver disease.

Topical application of glycyrrhizin preparation ameliorates experimentally induced colitis in rats

AIM: To examine the efficacy of glycyrrhizin preparation (GL-p) in the treatment of a rat model of ulcerative colitis (UC).

METHODS: Experimental colitis was induced by oral administration of dextran sodium sulfate. Rats with colitis were intrarectally administered GL-p or saline. The extent of colitis was evaluated based on body weight gain, colon wet weight, and macroscopic damage score. The expression levels of pro-inflammatory cytokines and chemokines in the inflamed mucosa were measured by cytokine antibody array analysis. The effect of GL-p on myeloperoxidase (MPO) activity in the inflamed mucosa and purified enzyme was assayed.

RESULTS: GL-p treatment significantly ameliorated the extent of colitis compared to sham treatment with saline. Cytokine antibody array analysis showed that GL-p treatment significantly decreased the expression levels of pro-inflammatory cytokines and chemokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, cytokine-induced neutrophil chemoattractant-2, and monocyte chemoattractant protein-1 in the inflamed mucosa. Furthermore, GL-p inhibited the oxidative activity of mucosal and purified MPO.

CONCLUSION: GL-p enema has a therapeutic effect on experimental colitis in rats and may be useful in the treatment of UC.

Effect of glycyrrhizin on CYP2C19 and CYP3A4 activity in healthy volunteers with different CYP2C19 genotypes

The objective of this study was to investigate the interaction between glycyrrhizin and omeprazole and observe the effects of glycyrrhizin on CYP2C19 and CYP3A4 activities in healthy Chinese male volunteers with different CYP2C19 genotypes. Eighteen healthy subjects (six CYP2C19*1/*1, five CYP2C19*1/*2, one CYP2C19*1/*3, five CYP2C19*2/*2 and one CYP2C19*2/*3) were enrolled in a two-phase randomized crossover trial. In each phase, all subjects received placebo or glycyrrhizin salt tablet 150 mg twice daily for 14 consecutive days. The pharmacokinetics of omeprazole (20 mg orally on day 15) was determined for up to 12 h following administration by high-performance liquid chromatography. After 14-day treatment of glycyrrhizin, plasma omeprazole significantly decreased, and those of omeprazole sulfone significantly increased. However, plasma concenetrations of 5-hydroxyomeprazole did not significantly change. The ratio of AUC(0-infinity) of omeprazole to omeprazole sulfone decreased by 43.93% + or - 13.56% (p = 0.009) in CYP2C19*1/*1, 44.85% + or - 14.84% (p = 0.002) in CYP2C19*1/*2 or *3 and 36.16% + or - 7.52% (p < 0.001) in CYP2C19*2/*2 or *3 while those of omeprazole to 5-hydroxyomeprazole did not change significantly in all three genotypes. No significant differences in glycyrrhizin response were found among CYP2C19 genotypes. Glycyrrhizin induces CYP3A4-catalyzed sulfoxidation of omeprazole and leads to decreased omeprazole plasma concentrations, but has no significant impact on CYP2C19-dependent hydroxylation of omeprazole.

EST analysis reveals putative genes involved in glycyrrhizin biosynthesis

Background

Glycyrrhiza uralensis is one of the most popular medicinal plants in the world and is also widely used in the flavoring of food and tobacco. Due to limited genomic and transcriptomic data, the biosynthetic pathway of glycyrrhizin, the major bioactive compound in G. uralensis, is currently unclear. Identification of candidate genes involved in the glycyrrhizin biosynthetic pathway will significantly contribute to the understanding of the biosynthetic and medicinal chemistry of this compound.

Results

We used the 454 GS FLX platform and Titanium regents to produce a substantial expressed sequence tag (EST) dataset from the vegetative organs of G. uralensis. A total of 59,219 ESTs with an average read length of 409 bp were generated. 454 ESTs were combined with the 50,666 G. uralensis ESTs in GenBank. The combined ESTs were assembled into 27,229 unique sequences (11,694 contigs and 15,535 singletons). A total of 20,437 unique gene elements representing approximately 10,000 independent transcripts were annotated using BLAST searches (e-value ≤ 1e-5) against the SwissProt, KEGG, TAIR, Nr and Nt databases. The assembled sequences were annotated with gene names and Gene Ontology (GO) terms. With respect to the genes related to glycyrrhizin metabolism, genes encoding 16 enzymes of the 18 total steps of the glycyrrhizin skeleton synthesis pathway were found. To identify novel genes that encode cytochrome P450 enzymes and glycosyltransferases, which are related to glycyrrhizin metabolism, a total of 125 and 172 unigenes were found to be homologous to cytochrome P450s and glycosyltransferases, respectively. The cytochrome P450 candidate genes were classified into 32 CYP families, while the glycosyltransferase candidate genes were classified into 45 categories by GO analysis. Finally, 3 cytochrome P450 enzymes and 6 glycosyltransferases were selected as the candidates most likely to be involved in glycyrrhizin biosynthesis through an organ-specific expression pattern analysis based on real-time PCR.

Conclusions

Using the 454 GS FLX platform and Titanium reagents, our study provides a high-quality EST database for G. uralensis. Based on the EST analysis, novel candidate genes related to the secondary metabolite pathway of glycyrrhizin, including novel genes encoding cytochrome P450s and glycosyltransferases, were found. With the assistance of organ-specific expression pattern analysis, 3 unigenes encoding cytochrome P450s and 6 unigenes encoding glycosyltransferases were selected as the candidates most likely to be involved in glycyrrhizin biosynthesis.

Effect of glycyrrhizin on the activity of CYP3A enzyme in humans

BACKGROUND

Glycyrrhizin is a major ingredient of licorice which is widely used in the treatment of various diseases such as chronic hepatitis. Licorice or glycyrrhizin has been shown to alter the activity of CYP3A in rodents. The influence of glycyrrhizin on CYP3A has not been elucidated in humans.

OBJECTIVE

To investigate the effects of repeated glycyrrhizin ingestion on the oral pharmacokinetics of midazolam, a probe drug for CYP3A activity in humans.

METHODS

Sixteen healthy adult male subjects were enrolled in a two-phase randomized crossover design. In each phase the volunteers received placebo or glycyrrhizin for 14 days. On the 15th day, midazolam was administered and blood samples were obtained to determine midazolam plasma concentrations. Bioequivalence was assessed by determining geometric mean ratios (GMRs) and 90% confidence intervals (90% CI).

RESULTS

The geometric mean (geometric coefficient of variation) for the AUC(0-infinity) of midazolam in the placebo group was 196.4 ng x h/ml (30.3%) and after glycyrrhizin treatment, 151.3 ng x h/ml (34.7%). The GMRs and 90% CI for AUC(0-infinity) and Cmax of midazolam in the presence/ absence of glycyrrhizin were 0.77 (0.70, 0.89) and 0.83 (0.74, 1.01), respectively. The 90% CI for AUC(0-infinity) and Cmax for the GMR of glycyrrhizin over placebo were both out of the no-effect boundaries of 0.80-1.25.

CONCLUSIONS

Administration of glycyrrhizin resulted in a modest induction of CYP3A that was clinically relevant according to the bioequivalence analysis.

Bioactive microbial metabolites from glycyrrhetinic acid

Biotransformation of 18beta-glycyrrhetinic acid, using Absidia pseudocylinderospora ATCC 24169, Gliocladium viride ATCC 10097 and Cunninghamella echinulata ATCC 8688a afforded seven metabolites, which were identified by different spectroscopic techniques (1H, 13C NMR, DEPT, 1H-1H COSY, HMBC and HMQC). Three of these metabolites, viz. 15alpha-hydroxy-18alpha-glycyrrhetinic acid, 13beta-hydroxy-7alpha,27-oxy-12-dihydro-18beta-glycyrrhetinic acid and 1alpha-hydroxy-18beta-glycyrrhetinic acid are new. The 13C NMR data and full assignment for the known metabolite 7beta, 15alpha-dihydroxy-18beta-glycyrrhetinic acid are described here for the first time. The major metabolites were evaluated for their hepatoprotective activity using different in vitro and in vivo models. These included protection against FeCl3/ascorbic acid-induced lipid peroxidation of normal mice liver homogenate, induction of nitric oxide (NO) production in rat macrophages and in vivo hepatoprotection against CCl4-induced hepatotoxicity in albino mice.

Glycyrrhizin, the main active compound in liquorice, attenuates pro-inflammatory responses by interfering with membrane-dependent receptor signalling

The triterpene glycoside glycyrrhizin is the main active compound in liquorice. It is used as a herbal medicine owing to its anticancer, antiviral and anti-inflammatory properties. Its mode of action, however, remains widely unknown. In the present study, we aimed to elucidate the molecular mechanism of glycyrrhizin in attenuating inflammatory responses in macrophages. Using microarray analysis, we found that glycyrrhizin caused a broad block in the induction of pro-inflammatory mediators induced by the TLR (Toll-like receptor) 9 agonist CpG-DNA in RAW 264.7 cells. Furthermore, we found that glycyrrhizin also strongly attenuated inflammatory responses induced by TLR3 and TLR4 ligands. The inhibition was accompanied by decreased activation not only of the NF-kappaB (nuclear factor kappaB) pathway but also of the parallel MAPK (mitogen-activated protein kinase) signalling cascade upon stimulation with TLR9 and TLR4 agonists. Further analysis of upstream events revealed that glycyrrhizin treatment decreased cellular attachment and/or uptake of CpG-DNA and strongly impaired TLR4 internalization. Moreover, we found that the anti-inflammatory effects were specific for membrane-dependent receptor-mediated stimuli, as glycyrrhizin was ineffective in blocking Tnfa (tumour necrosis factor alpha gene) induction upon stimulation with PMA, a receptor- and membrane-independent stimulus. These observations suggest that the broad anti-inflammatory activity of glycyrrhizin is mediated by the interaction with the lipid bilayer, thereby attenuating receptor-mediated signalling.

Inhibitory effect of glycyrrhizin on the neutrophil-dependent increase of R5 HIV replication in cultures of macrophages

It has been described that polymorphonuclear neutrophils (PMNs) enhance the replication of CC‐chemokine receptor 5/macrophage‐tropic (R5) HIV in cultures of monocyte‐derived macrophages (MDMs). In this study, the inhibitory effect of glycyrrhizin (GL) on R5 HIV replication influenced by PMNs was investigated in MDM cultures. The replication of R5 HIV in MDMs was greatly enhanced when cells were co‐cultured with freshly isolated PMNs (syngeneic to MDMs). When GL was added to this culture, however, the viral replication enhanced by PMNs was completely inhibited. CCL2 and interleukin 10 (IL‐10) were produced in cultures of PMNs exposed to R5 HIV, and the replication of R5 HIV was greatly enhanced in MDM cultures supplemented with a mixture of recombinant CCL2 and IL‐10. However, CCL2 and IL‐10 were not produced by PMNs exposed to R5 HIV, when GL was added to the cultures. In the presence of GL, these soluble factors were not detected in co‐cultures of MDMs and PMNs exposed to R5 HIV. In addition, the replication of R5 HIV in MDMs stimulated with CCL2 and IL‐10 was not directly influenced by GL. These results indicated that GL suppresses the PMN‐dependent increase of R5 HIV replication in MDMs through inhibiting CCL2/IL‐10 production by PMNs stimulated with R5 HIV.

Optimization of Microwave-Assisted Extraction for the Determination of Glycyrrhizin in Menthazin Herbal Drug by Experimental Design Methodology

In the present study, a microwave-assisted extraction (MAE) method has been investigated for the extraction of glycyrrhizin from Menthazin herbal drug. The extracted samples have been analyzed by a developed reversed-phase liquid chromatography with ultraviolet detection. The separation was performed by a Eurospher-100 C₈ reversed-phase column (250 × 4.6 mm i.d., 5 μm) and the mobile phase consisted of methanol:acetonitrile:water:glacial acetic acid (30:30:40:1 v/v/v/v) with a flow rate of 0.8 mL min⁻¹. The extraction procedure has been screened by a two level full factorial design for determination of statistically significant parameters. Thereafter, the identified parameters, extraction temperature, time and solvent volume were optimized by a Box–Behnken design. The proposed mathematical model was based on analysis of variance results and correctly explained the behavior of the response in the experimental domain. R² value adjusted for numbers of degrees of freedom was 0.9915 and P-value for lack of fit, 0.8499 at the 95% confidence level, P > 0.05. The optimal condition identified were extraction temperature, 70 °C, time, 13.8 min and solvent volume 2.0 mL. To evaluate the applicability of the proposed MAE method, results were compared with those obtained with the liquid extraction method. Extraction efficiency and precision were higher when MAE has been used. The proposed method allows extracting the glycyrrhizin in a small quantity of solvent and faster than the liquid extraction method.

Sustained virological response reduces incidence of onset of type 2 diabetes in chronic hepatitis C

Diabetes is present in patients with chronic hepatitis C virus infection. The aim of this retrospective cohort study was to assess the cumulative development incidence and predictive factors for type 2 diabetes after the termination of interferon therapy in Japanese patients positive for hepatitis C virus (HCV). A total of 2,842 HCV-positive patients treated with interferon (IFN) monotherapy or combination therapy with IFN and ribavirin were enrolled. The mean observation period was 6.4 years. An overnight (12-hour) fasting blood sample or a casual blood sample was taken for routine analyses during follow-up. The primary goal was the onset of type 2 diabetes. Evaluation was performed by using the Kaplan-Meier method and Cox proportional hazard analysis. Of 2,842 HCV patients, 143 patients developed type 2 diabetes. The cumulative development rate of type 2 diabetes was 3.6% at 5 years, 8.0% at 10 years, and 17.0% at 15 years. Multivariate Cox proportional hazard analysis revealed that type 2 diabetes development after the termination of IFN therapy occurred when histological staging was advanced (hazard ratio 3.30; 95% confidence interval [CI] 2.06-5.28; P < 0.001), sustained virological response was not achieved (hazard ratio 2.73; 95% CI 1.77-4.20; P < 0.001), the patient had pre-diabetes (hazard ratio 2.19; 95% CI 1.43-3.37; P < 0.001), and age was >or=50 years (hazard ratio 2.10; 95% CI 1.38-3.18; P < 0.001).

CONCLUSION

Our results indicate sustained virological response causes a two-thirds reduction in the risk of type 2 diabetes development in HCV-positive patients treated with IFN.

Hepatitis C virus enhances incidence of idiopathic pulmonary fibrosis

AIM: To investigate the cumulative development incidence and predictive factors for idiopathic pulmonary fibrosis in hepatitis C virus (HCV) positive patients.

METHODS: We studied 6150 HCV infected patients who were between 40-70 years old (HCV-group). Another 2050 patients with hepatitis B virus (HBV) were selected as control (HBV-group). The mean observation period was 8.0 ± 5.9 years in HCV-group and 6.3 ± 5.5 years in HBV-group. The primary goal is the development of idiopathic pulmonary fibrosis (IPF) in both groups. The cumulative appearance rate of IPF and independent factors associated with the incidence rate of IPF were calculated using the Kaplan-Meier method and the Cox proportional hazard model. All of the studies were performed retrospectively by collecting and analyzing data from the patient records in our hospital.

RESULTS: Fifteen patients in HCV-group developed IPF. On the other hand, none of the patients developed IPF in HBV-group. In HCV-group, the cumulative rates of IPF development were 0.3% at 10th year and 0.9% at 20th year. The IPF development rate in HCV-group was higher than that in HBV-group (P = 0.021). The IPF development rate in patients with HCV or HBV was high with statistical significance in the following cases: (1) patients ≥ 55 years (P < 0.001); (2) patients who had smoking index (package per day × year) of ≥ 20 (P = 0.002); (3) patients with liver cirrhosis (P = 0.042).

CONCLUSION: Our results indicate that age, smoking and liver cirrhosis enhance the development of IPF in HCV positive patients.

Licorice beta-amyrin 11-oxidase, a cytochrome P450 with a key role in the biosynthesis of the triterpene sweetener glycyrrhizin

Glycyrrhizin, a major bioactive compound derived from the underground parts of Glycyrrhiza (licorice) plants, is a triterpene saponin that possesses a wide range of pharmacological properties and is used worldwide as a natural sweetener. Because of its economic value, the biosynthesis of glycyrrhizin has received considerable attention. Glycyrrhizin is most likely derived from the triterpene beta-amyrin, an initial product of the cyclization of 2,3-oxidosqualene. The subsequent steps in glycyrrhizin biosynthesis are believed to involve a series of oxidative reactions at the C-11 and C-30 positions, followed by glycosyl transfers to the C-3 hydroxyl group; however, no genes encoding relevant oxidases or glycosyltransferases have been identified. Here we report the successful identification of CYP88D6, a cytochrome P450 monooxygenase (P450) gene, as a glycyrrhizin-biosynthetic gene, by transcript profiling-based selection from a collection of licorice expressed sequence tags (ESTs). CYP88D6 was characterized by in vitro enzymatic activity assays and shown to catalyze the sequential two-step oxidation of beta-amyrin at C-11 to produce 11-oxo-beta-amyrin, a possible biosynthetic intermediate between beta-amyrin and glycyrrhizin. CYP88D6 coexpressed with beta-amyrin synthase in yeast also catalyzed in vivo oxidation of beta-amyrin to 11-oxo-beta-amyrin. CYP88D6 expression was detected in the roots and stolons by RT-PCR; however, no amplification was observed in the leaves or stems, which is consistent with the accumulation pattern of glycyrrhizin in planta. These results suggest a role for CYP88D6 as a beta-amyrin 11-oxidase in the glycyrrhizin pathway.

Potential of laparoscopy in chronic liver disease with hepatitis B and C viruses

AIM

The definitive diagnosis of chronic liver disease is made either by a histological examination of a biopsy specimen or upon visualization of the liver surface at laparoscopy. The aim of this retrospective cohort study is to assess whether histological or laparoscopic findings are associated with hepatocellular carcinoma (HCC) development.

METHODS

A retrospective review of paired laparoscopy and histology reports was performed on 4124 hepatitis virus-positive patients who underwent laparoscopy: 2804 patients had hepatitis C virus (HCV group) and 1320 patients had hepatitis B virus (HBV group). Based on the irregularities of the liver surface, the laparoscopic findings were classified into three groups in progression order: smooth, irregular, or nodular. The histological findings were classified according to the extent of fibrosis into four stages (stages 1-4) in progression order.

RESULTS

The number of patients with HCC development was 565 in the HCV group and 115 in the HBV group. The Coxregression hazard model showed that HCC appearance in the HCV group was independently associated with laparoscopic findings (relative risk based on every progression of one rank [RR], RR = 4.31, P < 0.0001) and histological findings (RR = 2.56, P < 0.0001). In the HBV group, however, HCC appearance in was mainly associated with laparoscopic findings (RR = 2.12, P < 0.0001) compared to histological findings (RR = 1.13, P = 0.403).

CONCLUSION

Our data indicate that laparoscopic findings of the liver are dominant predictors for HCC development compared with histological findings in patients with HBV.

Antiviral effects of Glycyrrhiza species

Historical sources for the use of Glycyrrhiza species include ancient manuscripts from China, India and Greece. They all mention its use for symptoms of viral respiratory tract infections and hepatitis. Randomized controlled trials confirmed that the Glycyrrhiza glabra derived compound glycyrrhizin and its derivatives reduced hepatocellular damage in chronic hepatitis B and C. In hepatitis C virus‐induced cirrhosis the risk of hepatocellular carcinoma was reduced. Animal studies demonstrated a reduction of mortality and viral activity in herpes simplex virus encephalitis and influenza A virus pneumonia. In vitro studies revealed antiviral activity against HIV‐1, SARS related coronavirus, respiratory syncytial virus, arboviruses, vaccinia virus and vesicular stomatitis virus.

Mechanisms for antiviral activity of Glycyrrhiza spp. include reduced transport to the membrane and sialylation of hepatitis B virus surface antigen, reduction of membrane fluidity leading to inhibition of fusion of the viral membrane of HIV‐1 with the cell, induction of interferon gamma in T‐cells, inhibition of phosphorylating enzymes in vesicular stomatitis virus infection and reduction of viral latency.

Future research needs to explore the potency of compounds derived from licorice in prevention and treatment of influenza A virus pneumonia and as an adjuvant treatment in patients infected with HIV resistant to antiretroviral drugs. Copyright © 2007 John Wiley & Sons, Ltd.

Antifibrotic effects of a herbal combination regimen on hepatic fibrotic rats

Liver fibrosis has been characterized as chronic inflammatory processes involving multiple molecular pathogenetic pathways. This therapeutic study investigated whether a combination regimen of Salvia miltiorrhiza (S), Ligusticum chuanxiong (L) and Glycyrrhiza glabra (G) exerted in vivo antifibrotic effects on rats with hepatic fibrosis. Fibrosis was induced in rats by dimethylnitrosamine (DMN) administration for 4 weeks. Fibrotic rats were randomly assigned to one of the three groups: control, SLG (50 mg/kg) or silymarin (50 mg/kg), each given by gavage twice daily for 3 weeks starting 1 week after DMN injection. The results showed that fibrosis scores of livers from DMN-treated rats with SLG (1.13 +/- 0.13) were significantly reduced in comparison with DMN-treated rats receiving vehicle (1.63 +/- 0.18). Moreover, the hepatic collagen content of DMN rats was significantly reduced by either SLG or silymarin treatment. The double immunohistochemical staining results also showed that alpha-SMA positive cells with NF kappa B nuclear translocation were decreased in the fibrotic livers by SLG and silymarin treatments. The mRNA expression levels of TGF-beta1, alpha-SMA, collagen1 alpha 2, iNOS and ICAM-1 genes were attenuated by SLG and silymarin treatment. The results showed that SLG exerted antifibrotic effects in rats with DMN-induced hepatic fibrosis.

Prevention of free fatty acid-induced hepatic lipotoxicity by 18beta-glycyrrhetinic acid through lysosomal and mitochondrial pathways

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and affects millions of people worldwide. Despite the increasing prevalence of NAFLD, the exact molecular/cellular mechanisms remain obscure and effective therapeutic strategies are still limited. It is well-accepted that free fatty acid (FFA)-induced lipotoxicity plays a pivotal role in the pathogenesis of NAFLD. Inhibition of FFA-associated hepatic toxicity represents a potential therapeutic strategy. Glycyrrhizin (GL), the major bioactive component of licorice root extract, has a variety of pharmacological properties including anti-inflammatory, antioxidant, and immune-modulating activities. GL has been used to treat hepatitis to reduce liver inflammation and hepatic injury; however, the mechanism underlying the antihepatic injury property of GL is still poorly understood. In this report, we provide evidence that 18 beta-glycyrrhetinic acid (GA), the biologically active metabolite of GL, prevented FFA-induced lipid accumulation and cell apoptosis in in vitro HepG2 (human liver cell line) NAFLD models. GA also prevented high fat diet (HFD)-induced hepatic lipotoxicity and liver injury in in vivo rat NAFLD models. GA was found to stabilize lysosomal membranes, inhibit cathepsin B expression and enzyme activity, inhibit mitochondrial cytochrome c release, and reduce FFA-induced oxidative stress. These characteristics may represent major cellular mechanisms, which account for its protective effects on FFA/HFD-induced hepatic lipotoxicity.

CONCLUSION

GA significantly reduced FFA/HFD-induced hepatic lipotoxicity by stabilizing the integrity of lysosomes and mitochondria and inhibiting cathepsin B expression and enzyme activity.

Review of pharmacological effects of Glycyrrhiza sp. and its bioactive compounds

The roots and rhizomes of licorice (Glycyrrhiza) species have long been used worldwide as a herbal medicine and natural sweetener. Licorice root is a traditional medicine used mainly for the treatment of peptic ulcer, hepatitis C, and pulmonary and skin diseases, although clinical and experimental studies suggest that it has several other useful pharmacological properties such as antiinflammatory, antiviral, antimicrobial, antioxidative, anticancer activities, immunomodulatory, hepatoprotective and cardioprotective effects. A large number of components have been isolated from licorice, including triterpene saponins, flavonoids, isoflavonoids and chalcones, with glycyrrhizic acid normally being considered to be the main biologically active component. This review summarizes the phytochemical, pharmacological and pharmacokinetics data, together with the clinical and adverse effects of licorice and its bioactive components.

Down-regulation of a hepatic transporter multidrug resistance-associated protein 2 is involved in alteration of pharmacokinetics of glycyrrhizin and its metabolites in a rat model of chronic liver injury

Glycyrrhizin (GL) has been used to treat chronic hepatitis in Japan and Europe. It is thought to induce pseudoaldosteronism via inhibition of type 2 11beta-hydroxysteroid dehydrogenase (11beta-HSD2) by glycyrrhetinic acid (GA), a major metabolite of GL. A previous clinical study suggested that 3-monoglucuronyl-glycyrrhetinic acid (3MGA), another metabolite of GL, might play a more important role in the pathogenesis of pseudoaldosteronism. The present study evaluates the pharmacokinetics of GL and its metabolites in rats with chronic liver injury induced by a choline-deficient l-amino acid-defined (CDAA) diet to clarify the relationship between 3MGA and pseudoaldosteronism. In rats fed a CDAA diet, plasma concentrations and urinary eliminations of GL and 3MGA were markedly higher than in the rats fed the control diet; the plasma concentration of GA was unaffected when GL was orally administered. Immunohistochemical analysis revealed the suppression of levels of multidrug resistance-associated protein (Mrp) 2 and its localization in the hepatic tissue of rats fed a CDAA diet. When 3MGA was i.v. injected in rats fed a CDAA diet or injected in Mrp2-dysfunctional Eisai hyperbilirubinemic rats, plasma concentrations of 3MGA were higher, and biliary excretion of 3MGA was lower than in each control group. The results suggested that 3MGA would be excreted to bile via hepatic Mrp2 and that its dysfunction would reduce 3MGA clearance. 3MGA accumulated by liver fibrosis resulted in the increased excretion through renal tubule and might be strongly related to the pathogenesis of pseudoaldosteronism because 11beta-HSD2 is expressed in renal tubular epithelial cells.

Glycyrrhizin inhibits interleukin-8 production and nuclear factor-kappaB activity in lung epithelial cells, but not through glucocorticoid receptors

This study was designed to examine the glucocorticoid-like inhibitory effect of glycyrrhizin (GL) on interleukin (IL)-8 production in A549 lung epithelial cells. GL, as well as dexamethasone (DEX) inhibited both tumor necrosis factor (TNF)-α –and IL-1β –induced IL-8 production, mRNA expression, and promoter activity in A549 cells. Both GL and DEX inhibited transactivation of nuclear factor (NF)-κ B, without inhibiting translocation of the NF-κ B p65 subunit to the nucleus. However, the effect of GL was insensitive to RU486, a GR antagonist, and to GR knockdown by siRNA. Furthermore, only GL inhibited DNA binding of p65 to the IL-8 promoter region. These findings indicated that GL had a glucocorticoid-like inhibitory effect on IL-8 production via a mechanism that differs from that of glucocorticoids.

Pharmacological and chemical effects of cigarette additives

We investigated tobacco industry documents and other sources for evidence of possible pharmacological and chemical effects of tobacco additives. Our findings indicated that more than 100 of 599 documented cigarette additives have pharmacological actions that camouflage the odor of environmental tobacco smoke emitted from cigarettes, enhance or maintain nicotine delivery, could increase the addictiveness of cigarettes, and mask symptoms and illnesses associated with smoking behaviors. Whether such uses were specifically intended for these agents is unknown. Our results provide a clear rationale for regulatory control of tobacco additives.

[Novel formulations of a liver protection drug glycyrrhizin]

In Japan, glycyrrhizin injections have been used as a therapeutic drug for allergy inflammation since 1948 and for chronic hepatitis since 1979. A 20 ml injection of glycyrrhizin contains 53 mg of monoammonium glycyrrhizinate (40 mg as glycyrrhizin acid), 400 mg of glycine, and 20 mg of L-cysteine. Patients receiving glycyrrhizin injections two or three times per week are forced to accept a decline in quality of life. Because administering glycyrrhizin by injection has some disadvantages, many researchers have systematically searched for novel glycyrrhizin formulations that can be administered through oral, rectal, intranasal, and subcutaneous routes. There are two problems, however, in developing new formulations: (1) glycyrrhizin has low membrane permeability and is thus poorly absorbed, and (2) highly concentrated glycyrrhizin readily forms gels in aqueous solutions. Here, we describe the utility of glycyrrhizin formulations prepared in safe solubility agents and absorption-enhancing agents, as assessed in animal experiments. We also discuss pharmaceutical issues in developing various glycyrrhizin formulations. In the near future, convenient pharmaceutical preparations of glycyrrhizin will be developed for chronic hepatitis patients who require glycyrrhizin therapy.

Phase I safety and pharmacokinetic study of magnesium isoglycyrrhizinate after single and multiple intravenous doses in chinese healthy volunteers

The safety and pharmacokinetics of magnesium isoglycyrrhizinate were assessed in healthy Chinese volunteers. In the single-dose format of this pharmacokinetic study, 100-, 200-, and 300-mg doses of magnesium isoglycyrrhizinate were given by intravenous infusion. The results indicated that the plasma levels were directly proportional to the administered dose, with the mean C(max) and AUC(0-72) ranging from approximately 28.79 to 99.28 mg x L(-1) and 448.68 to 1688.42 mg x h x L(-1) over the dose range. In the multiple-dose format of this pharmacokinetic study, 100 mg magnesium isoglycyrrhizinate was administrated once daily for 9 days. Moderate drug accumulation was noted, which was attributable to the drug's long terminal half-life of 19 to 31 hours. The distribution and elimination rate of magnesium isoglycyrrhizinate had no changes. It had a favorable pharmacokinetics and safety profile that enables the drug to be explored in future clinical studies that target patients with hepatic impairment.

A possible involvement of 3-monoglucuronyl-glycyrrhetinic acid, a metabolite of glycyrrhizin (GL), in GL-induced pseudoaldosteronism

Glycyrrhizin (GL), a major ingredient of Glycyrrhiza Radix (licorice), is widely used to treat various disorders or as a sweetener. It is also known that GL occasionally induces pseudoaldosteronism. It is conceivable that the active form of GL in pseudoaldosteronism induction is glycyrrhetinic acid (GA). Although it is reported that 3-monoglucuronyl-glycyrrhetinic acid (3MGA) is detectable specifically in the plasma of patients with GL-induced hypokalemia, pharmacokinetics and a hypokalemia induction mode of action for 3MGA have not been clarified. We investigated the toxicokinetics of GL, GA and 3MGA in a single or multiple oral administration of GL. The results suggested that higher blood concentrations of 3MGA were maintained by the multiple administration compared to the single dose, whereas the concentrations of GA and GL showed no difference. We injected 3MGA intravenously and found that it can decrease the plasma potassium level (PPL) in vivo. It is clinically recommended to avoid a combination treatment of GL and furosemide. While treatment with a low dosage of furosemide had no effect on PPL, the multiple administration of GL and furosemide markedly decreased PPL compared to the effect of administering GL alone. In the single dosage regime, there was no difference between PPL after the combination treatment and after administering GL alone. Collectively, these findings suggested that accumulation of 3MGA may be involved in the pathogenesis of pseudoaldosteronism induced by chronic GL treatment.

Complementary and alternative Medicine (CAM) for the Treatment of Chronic Hepatitis B and C: A Review

Complementary and alternative medicine (CAM) has been used for centuries in China and Japan to treat various illnesses, including viral hepatitis. Several therapeutic approaches constitute CAM, the most relevant for this review being the use of herbals. However, profound disagreements exist between conventional and alternative medicine practitioners regarding their value. Western medical advocates cite deep concerns about the purity of most herbals because of lack of standardized production, the paucity of pharmacokinetic data, the fact that few well-designed randomized, controlled trials of these products have been performed and the evidence that some herbals have been responsible for severe adverse effects. Nevertheless, many in the public, even in western countries, turn to the use of herbals, believing that they must be safe and effective because they are ‘natural’ and have been used for centuries, and because of dissatisfaction with conventional medicine. Accordingly, their use in western countries and the costs incurred have increased each year. While there is evidence that some herbals have physiological effects, there still is insufficient evidence to recommend their use. This paper reviews the classification, epidemiology and philosophy of CAM, and the reasons advanced for herbal use to treat viral hepatitis. The criteria necessary to develop a potential pharmacological agent are presented, as well as the requirements for conducting a scientifically valid treatment trial of herbals. Five herbals used in the past to treat viral hepatitis are reviewed and evaluated for the quality of their studies and mention is made of herbals known to have adverse effects.

Herbal medicine in the treatment of liver diseases

Herbal drugs have become increasingly popular and their use is widespread. Licensing regulations and pharmacovigilance regarding herbal products are still incomplete and clearcut proof of their efficacy in liver diseases is sparse. Nevertheless, a number of herbals show promising activity including silymarin for antifibrotic treatment, phyllantus amarus in chronic hepatitis B, glycyrrhizin to treat chronic viral hepatitis, and a number of herbal combinations from China and Japan that deserve testing in appropriate studies. Apart from therapeutic properties, reports are accumulating about liver injury after the intake of herbals, including those advertised for liver diseases. Acute and/or chronic liver damage occurred after ingestion of some Chinese herbs, herbals that contain pyrrolizidine alkaloids, germander, greater celandine, kava, atractylis gummifera, callilepsis laureola, senna alkaloids, chaparral and many others. Since the evidence supporting the use of botanicals to treat chronic liver diseases is insufficient and only few of them are well standardised and free of potential serious side effects, most of these medications are not recommended outside clinical trials. Particularly with regard to the latter, adequately powered randomised-controlled clinical trials with well-selected end points are needed to assess the role of herbal therapy for liver diseases.

Glycyrrhizin inhibits the manifestations of anti-inflammatory responses that appear in association with systemic inflammatory response syndrome (SIRS)-like reactions

In association with the systemic inflammatory response syndrome (SIRS), anti-inflammatory response syndrome is commonly manifested in patients with trauma, burn injury, and after major surgery. These patients are increasingly susceptible to infection with various pathogens due to the excessive release of anti-inflammatory cytokines from anti-inflammatory effector cells. Recently, CC-chemokine ligand 2 (CCL2) found in the sera of mice with pancreatitis was identified as an active molecule for SIRS-associated anti-inflammatory response manifestation. Also, the inhibitory activity of glycyrrhizin (GL) on CCL2 production was reported. Therefore, the effect of GL on SIRS-associated anti-inflammatory response manifestation was investigated in a murine SIRS model. Without any stimulation, splenic T cells from mice 5 days after SIRS induction produced cytokines associated with anti-inflammatory response manifestation. However, these cytokines were not produced by splenic T cells from SIRS mice previously treated with GL. In dual-chamber transwells, IL-4-producing cells were generated from normal T cells cultured with peripheral blood polymorphonuclear neutrophils (PMN) from SIRS mice. However, IL-4-producing cells were not generated from normal T cells in transwell cultures performed with PMN from GL-treated SIRS mice. CCL2 was produced by PMN from SIRS mice, while this chemokine was not demonstrated in cultures of PMN from SIRS mice treated with GL. These results indicate that GL has the capacity to suppress SIRS-associated anti-inflammatory response manifestation through the inhibition of CCL2 production by PMN.

The use of selected nutrition supplements and complementary and alternative medicine in liver disease

Almost all patients with liver disease, especially advanced liver disease, have some evidence of malnutrition, including mineral/vitamin deficiency. A major health trend in the United States has been the significant growth in the use of complementary and alternative medicine (CAM), including nutrition supplements and herbal agents. In the 1990s, the United States government created the National Center for Complementary and Alternative Medicine (NCCAM), as well as the Office on Dietary Supplements, to extend our knowledge in these areas. CAM users are often highly educated and frequently use CAM therapy for chronic diseases, including chronic liver disease. Indeed, most studies suggest that patients with chronic liver disease frequently use nutrition supplements and CAM agents in addition to their traditional medicines. The purpose of this review is to provide an update on the role of nutrition supplements and herbals in liver disease. This article will focus mainly on 7 selected agents (vitamin E, zinc, magnesium, S-adenosylmethionine, betaine, silymarin, and glycyrrhizin), for which there have been not only in vitro and animal studies but also human clinical trials, and we will review both potential efficacy and safety issues.

Azathioprine hepatotoxicity and the protective effect of liquorice and glycyrrhizic acid

This study aimed to evaluate the responses of human hepatocytes to azathioprine hepatotoxicity in comparison with the well-studied azathioprine hepatotoxicity in rat hepatocytes and the effects of protective agents to suppress azathioprine hepatotoxicity. Azathioprine presented its hepatotoxicity at clinically relevant concentrations (lower than 10 microm) in primary rat hepatocytes after 48 h of treatment as shown by a severe decrease in cell viability as well as intracellular GSH depletion. However, primary human hepatocytes exhibited only significant intracellular GSH depletion after treatment with azathioprine at these clinically relevant concentrations, while a reduction in cell viability by 29% was only evidenced after 48 h of treatment with azathioprine at the high concentration of 50 microm. In addition, a monolayer culture of primary rat hepatocytes was used as an in vitro model to examine the protective effects of antihepatotoxic drugs including glutathione (GSH), N-acetylcysteine (NAC, a GSH precursor), liquorice and glycyrrhizic acid (GA), a major bioactive component of liquorice, against hepatotoxicity of 1 microm azathioprine. It was found that both liquorice and GA showed substantial protection according to assays of cell viability and intracellular GSH, while neither GSH nor NAC had such a protective function. Similarly, GA protected human hepatocytes from intracellular GSH depletion on exposure to 1 microm azathioprine. These results implied that GA or liquorice could be considered as potent protection agents against azathioprine hepatotoxicity.