Glycyrrhizic acid

Glycyrrhizic acid is a triterpenoid saponinl, extracted from the licorice root, with anti-tumor, anti-diabetic activities.

In Vitro:Glycyrrhizic acid shows a series of anti-cancer-related pharmacological activities, such as broad-spectrum anti-cancer ability, resistance to the tissue toxicity caused by chemotherapy and radiation, drug absorption enhancing effects and anti-multidrug resistance (MDR) mechanisms, as a carrier material in drug delivery systems[1]. In intestinal NCI-H716 cells that secretes GLP-1, Glycyrrhizic acid promotes GLP-1 secretion with a marked elevation of calcium levels. Glycyrrhizic acid can enhance GLP-1 secretion through TGR5 activation[2].

In Vivo:In type 1-like diabetic rats induced by streptozotocin (STZ-treated rats), Glycyrrhizic acid increases the level of plasma GLP-1, which is blocked by triamterene at a dose sufficient to inhibit Takeda G-protein-coupled receptor 5 (TGR5)[1].

References:
[1]. Su X, et al. Glycyrrhizic acid: A promising carrier material for anticancer therapy. Biomed Pharmacother. 2017 Sep 5;95:670-678 [2]. Wang LY, et al. Glycyrrhizic acid increases glucagon like peptide-1 secretion via TGR5 activation in type 1-like diabetic rats. Biomed Pharmacother. 2017 Sep 4;95:599-604.

Glycyrrhizic acid in the treatment of liver diseases: literature review.[Pubmed:24963489]

Biomed Res Int. 2014;2014:872139.

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

Growth inhibitory in vitro effects of glycyrrhizic acid in U251 glioblastoma cell line.[Pubmed:24514918]

Neurol Sci. 2014 Jul;35(7):1115-20.

Despite dramatic advances in cancer therapy, the overall prognosis of glioblastoma (GBM) remains dismal. Nuclear factor kappa-B (NF-kappaB) has been previously demonstrated to be constitutively activated in glioblastoma, and it was suggested as a potential therapeutic target. Glycyrrhizic acid (GA) has been proved to have cytotoxic effects in many cancer cell lines. However, its role in glioblastoma has not yet been addressed. Therefore, this study aimed to investigate the effects of GA on human glioblastoma U251 cell line. The effects of GA on proliferation of U251 cells were measured by CCK-8 assay and plate colony-forming test. Cellular apoptosis was detected by Hoechst 33258 fluorescent staining and flow cytometry with annexin V-FITC/PI dual staining. The expression of nuclear p65 protein, the active subunit of NF-kappaB, was determined by Western blot and immunofluorescence. Our results demonstrated that the survival rate and colony formation of U251 cells significantly decreased in a time- and dose-dependent manner after GA addition, and the apoptotic ratio of GA-treated groups was significantly higher than that of control groups. Furthermore, the expression of NF-kappaB-p65 in the nucleus was remarkably reduced after GA treatment. In conclusion, our findings suggest that GA treatment can confer inhibitory effects on human glioblastoma U251 cell line including inhibiting proliferation and inducing apoptosis, which is possibly related to the NF-kappaB mediated pathway.

Glycyrrhizic acid and 18beta-glycyrrhetinic acid modulate lipopolysaccharide-induced inflammatory response by suppression of NF-kappaB through PI3K p110delta and p110gamma inhibitions.[Pubmed:21644799]

J Agric Food Chem. 2011 Jul 27;59(14):7726-33.

The roots and rhizomes of licorice ( Glycyrrhia ) species have been used extensively as natural sweeteners and herbal medicines. The aim of this work was to determine the in vitro anti-inflammatory effects of Glycyrrhizic acid (GA) and 18beta-glycyrrhetinic acid (18betaGA) from licorice in a lipopolysaccharide (LPS)-stimulated macrophage model. The results showed that treatment with 25-75 muM GA or 18betaGA did not reduce RAW 264.7 cell viability but did significantly inhibit the production of LPS-induced nitric oxide (NO), prostaglandin E(2) (PGE(2)), and intracellular reactive oxygen species (ROS). Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR) analyses revealed that GA and 18betaGA significantly reduced the protein and mRNA levels of iNOS and COX-2 in LPS-induced macrophages. Both GA and 18betaGA inhibited the activation of NF-kappaB and the activities of phosphoinositide-3-kinase (PI3K) p110delta and p110gamma isoforms and then reduced the production of LPS-induced tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-1beta in a dose-dependent manner. In conclusion, these results indicate that GA and 18betaGA may provide an anti-inflammatory effect by attenuating the generation of excessive NO, PGE(2), and ROS and by suppressing the expression of pro-inflammatory genes through the inhibition of NF-kappaB and PI3K activity. Thus, the results suggest that GA and 18betaGA might serve as potential agents for the treatment of inflammatory-mediated diseases.

Glycyrrhizic acid as the antiviral component of Glycyrrhiza uralensis Fisch. against coxsackievirus A16 and enterovirus 71 of hand foot and mouth disease.[Pubmed:23454684]

J Ethnopharmacol. 2013 May 2;147(1):114-21.

ETHNOPHARMACOLOGICAL RELEVANCE: The radices of Glycyrrhiza uralensis Fisch. and herbal preparations containing Glycyrrhiza spp. have been used for thousands of years as an herbal medicine for the treatment of viral induced cough, viral hepatitis, and viral skin diseases like ulcers in China. Glycyrrhizic acid (GA) is considered the principal component in Glycyrrhiza spp. with a wide spectrum of antiviral activity. AIM: The present study attempt to validate the medicinal use of Glycyrrhiza uralensis for hand, foot and mouth disease (HFMD) and further to verify whether GA is an active antiviral component in the water extract of Glycyrrhiza uralensis. MATERIALS AND METHODS: Radices of Glycyrrhiza uralensis Fisch. were extracted with hot water. The chemical contents of the extract were profiled with HPLC analysis. The antiviral activity of the extract and the major components was evaluated against infection of enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) on Vero cells. The cytopathic effect caused by the infection was measured with MTT assay. Infectious virion production was determined using secondary infection assays and viral protein expression by immunoblotting analysis. RESULTS: The extract at 1000 mug/ml suppressed EV71 replication by 1.0 log and CVA16 by 1.5 logs. The antiviral activity was associated with the content of GA in the extract since selective depletion of GA from the extract by acid precipitation resulted in loss of antiviral activity. In contrast, the acid precipitant retained antiviral activity. The precipitant at a concentration of 200 mug/ml inhibited EV71 and CVA16 replication by 1.7 and 2.2 logs, respectively. Furthermore, GA dose-dependently blocked viral replication of EV71 and CVA16. At 3 mM, GA reduced infectious CVA16 and EV71 production by 3.5 and 2.2 logs, respectively. At 5mM, CVA16 production was reduced by 6.0 logs and EV71 by 4.0 logs. Both EV71 and CVA16 are members of Enterovirus genus, time-of-drug addition studies however showed that GA directly inactivated CVA16, while GA anti-EV71 effect was associated with an event(s) post virus cell entry. CONCLUSIONS: This study validated the medicinal usefulness of radices Glycyrrhiza uralensis against the etiological agents of HFMD. In addition to the identification of GA as the antiviral component of Glycyrrhiza uralensis against EV71 and CVA16 infection, this study also reveals that GA inhibits EV71 and CVA16 with distinct mechanisms.

Glycyrrhizic acid ameliorates HMGB1-mediated cell death and inflammation after renal ischemia reperfusion injury.[Pubmed:25059568]

Am J Nephrol. 2014;40(1):84-95.

BACKGROUND: Renal ischemia reperfusion injury (IRI) leads to acute kidney injury (AKI) and the death of tubular epithelial cells (TEC). The release of high-mobility group box-1 (HMGB1) and other damage-associated molecular pattern moieties from dying cells may promote organ dysfunction and inflammation by effects on TEC. Glycyrrhizic acid (GZA) is a functional inhibitor of HMGB1, but its ability to attenuate the HMGB1-mediated injury of TEC has not been tested. METHODS/RESULTS: In vitro, hypoxia and cytokine treatment killed TEC and resulted in the progressive release of HMGB1 into the supernatant. GZA reduced the hypoxia-induced TEC death as measured by annexin-V and propidium iodide. Hypoxia increased the expression of MCP-1 and CXCL1 in TEC, which was reduced by GZA in a dose-dependent manner. Similarly, the HMGB1 activation of effector NK cells was inhibited by GZA. To test the effect of HMGB1 neutralization by GZA in vivo, mice were subjected to renal IRI. HMGB1 protein expression increased progressively in kidneys from 4 to 24 h after ischemia and was detected in tubular cells by 4 h using immunohistochemistry. GZA preserved renal function after IRI and reduced tubular necrosis and neutrophil infiltration by histological analyses and ethidium homodimer staining. CONCLUSIONS: Importantly, these data demonstrate for the first time that AKI following hypoxia and renal IRI may be promoted by HMGB1 release, which can reduce the survival of TEC and augment inflammation. Inhibition of the interaction of HMGB1 with TEC through GZA may represent a therapeutic strategy for the attenuation of renal injury following IRI and transplantation.

Protective effects of glycyrrhizic acid by rectal treatment on a TNBS-induced rat colitis model.[Pubmed:21749393]

J Pharm Pharmacol. 2011 Mar;63(3):439-46.

OBJECTIVES: The research compared rectal and oral treatments with Glycyrrhizic acid for trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. METHODS: Wistar rats were randomly divided into seven groups: one normal and six with colitis, including TNBS, Glycyrrhizic acid (2, 10 and 50 mg/kg, rectally treated and 10 mg/kg, orally treated) and sulfasalazine (positive control, 225 mg/kg rectally treated) groups. Colitis was induced by colonic administration of TNBS in 30% ethanol. KEY FINDINGS: There were significant pathological changes in colon in TNBS-treated groups, and rectal Glycyrrhizic acid significantly attenuated colitis. Myeloperoxidase, tumour necrosis factor-alpha and interleukin-1beta of colon tissue or serum in the rectal Glycyrrhizic acid groups were markedly reduced when compared with the TNBS group, and lower than in the orally treated Glycyrrhizic acid group. It was further noted that, in vitro, Glycyrrhizic acid (up to 100 microg/ml) inhibited interleukin-6 and elevated interleukin-10 production in lipopolysaccharide-activated macrophages, and significantly inhibited proliferation of spleen lymphocytes, suggesting the immunoregulatory function of Glycyrrhizic acid. CONCLUSIONS: Rectally administered Glycyrrhizic acid has significant protective effects against TNBS-induced colitis in rats, and the rectal route may be a complementary treatment for inflammatory bowel disease.