18ß-Glycyrrhetinic acid monoglucuronide (GAMG) alleviates single-walled carbon nanotubes (SWCNT)-induced lung inflammation and fibrosis in mice through PI3K/AKT/NF-κB signaling pathway.

Carbon nanotubes (CNTs) have become far and wide used in a number of technical and merchant applications as a result of substantial advances in nanotechnology, therein single-walled carbon nanotubes (SWCNT) are one of the most promising nanoparticles. Inhaling CNTs has been linked to a variety of health problems, including lung fibrosis. Glycyrrhetinic acid 3-O-mono-ß-D-glucuronide (GAMG), a natural sweetener, has anti-inflammatory and antioxidant capacities. The purpose of this study was to evaluate the potential for GAMG to alleviate SWCNT-induced lung inflammation and fibrosis. During days 3-28 after SWCNT intratracheal administration, we observed a remarkable increase of IL-1ß, IL-6 and TNF-α in bronchoalveolar lavage fluid (BALF) on day 3 and collagen deposition on day 28. GAMG treatment remarkably ameliorated SWCNT-induced pulmonary fibrosis and attenuated SWCNT-induced inflammation and collagen deposition, and suppressed the activation of PI3K/AKT/NF-κB signaling pathway in the lungs. Therefore, GAMG has a therapeutic potential for the treatment of SWCNT-induced pulmonary fibrosis. Targeting PI3K/AKT/NF-κB signaling pathway may be a potential therapeutic approach to treat pulmonary fibrosis in mice with SWCNT.

Structure-based design of glycyrrhetinic acid derivatives as potent anti-sepsis agents targeting high-mobility group box-1.

Novel Glycyrrhetinic Acid (GA) derivatives with fused heterocycles on A ring were structure-based designed and synthesized. Their potential anti-inflammatory effects were investigated by a classical LPS stimulated macrophage model. Surface plasmon resonance (SPR) was used to verify the binding of GA analogues with HMGB1. A preliminary structure-activity relationship was summarized and an analogue GA-60 with ortho-methoxybenzyl pyrozole showed stronger anti-inflammatory effect and higher affinity for HMGB1 with a Kd value of 12.5 µM. In addition, this compound exhibited excellent inhibitory functions on NO (96%), TNF-α (94%), and IL-6 (100%), by interfering with phosphorylation of p38, ERK, JNK MAPKs, as well as that of NF-κB p65 and IKKα/ß. Moreover, GA-60 extended the survival of either the classic CLP-induced or LPS-induced sepsis mouse models. Molecular modeling predictions further supported these findings, clearly indicating that inhibiting HMGB1 release, using fused heterocyclic GA derivatives, is a promising strategy for treatment of sepsis.

Research progress on the protective effects of licorice-derived 18ß-glycyrrhetinic acid against liver injury.

The first description of the medical use of licorice appeared in "Shennong Bencao Jing", one of the well-known Chinese herbal medicine classic books dated back to 220-280 AD. As one of the most commonly prescribed Chinese herbal medicine, licorice is known as "Guo Lao", meaning "a national treasure" in China. Modern pharmacological investigations have confirmed that licorice possesses a number of biological activities, such as antioxidation, anti-inflammatory, antiviral, immune regulation, and liver protection. 18ß-glycyrrhetinic acid is one of the most extensively studied active integrants of licorice. Here, we provide an overview of the protective effects of 18ß-glycyrrhetinic acid against various acute and chronic liver diseases observed in experimental models, and summarize its pharmacological effects and potential toxic/side effects at higher doses. We also make additional comments on the important areas that may warrant further research to support appropriate clinical applications of 18ß-glycyrrhetinic acid and avoid potential risks.

Mitochondria-targeted triphenylphosphonium conjugated glycyrrhetinic acid derivatives as potent anticancer drugs.

Glycyrrhetinic acid has been usually studied for their anti-tumor activities. However, the low bioavailability and poor aqueous solubility as well as limited intracellular accumulation have limited their utility. In this present study, a series of new glycyrrhetinic acid conjugates with a triphenylphosphonium cation (TTP+) moiety, meant to specifically target them to tumor cells mitochondria, have been designed and synthesized. Among them, compound 2f possessed excellent antitumor activities against the tested human cancer cells, and simultaneously exhibited better cell selectivity between cancer cells and normal cells than glycyrrhetinic acid and HCPT. Moreover, 2f significantly induced cell cycle arrest at the G2/M phase, and effectively inhibited cancer cells proliferation and migration. Mechanism studies revealed that 2f triggered apoptosis through the mitochondrial pathway via the collapse of mitochondrial membrane potential, reactive oxygen species production and the activation of caspase-9 and caspase-3.

First Occurrence of a Furano-glycyrrhetinoate and Its Cytotoxicity.

(18α)-Glycyrrhetinic acid (4) was prepared from (18ß)-glycyrrhetinic acid (1), and the cytotoxicity of some derivatives was investigated by photometric SRB assays employing several human tumor cell lines. In summary, (18ß)-1 is slightly more cytotoxic than its (18α) epimer 4, but its cytotoxicity is negligible. Higher cytotoxicity was observed for the esters 2 and 5 and for the 3-O-acetylated esters 3 and 6. Cytotoxicity was improved dramatically when the hydroxyl group at position C-3 was replaced by an amino moiety. SeO2 oxidations gave access to a novel furano-glycyrrhetinoate 15. Interestingly, its seleno analog 16 is approximately five to six times less cytotoxic for the tumor cell lines tested, and tumor/non-tumor selectivity is lost upon replacement of the oxygen by a selenium substituent.

Aggravation of clozapine-induced hepatotoxicity by glycyrrhetinic acid in rats.

Clozapine (CLZ) was reported to be associated with hepatotoxicity. Glycyrrhetinic acid (GA) has a liver protective effect. Our preliminary experiments showed that GA aggravated rather than attenuated CLZ-induced hepatotoxicity in primary cultured rat hepatocytes. The study aimed to describe the enhancing effect of GA on CLZ-induced hepatotoxicity in vivo and in vitro. Data from primary cultured rat hepatocytes showed the decreased formation of metabolites demethylclozapine (nor-CLZ) and clozapine N-oxide (CLZ N-oxide). The results in vivo showed that 7-day CLZ treatment led to marked accumulation of triglyceride (TG) and increase in γ-glutamyl transpeptidase (γ-GT) activity, liver weight, and serum AST in rats. Co-administration of GA enhanced the increases in hepatic TG, γ-GT, liver weight, and serum total cholesterol induced by CLZ. GA decreased plasma concentrations of nor-CLZ and CLZ N-oxide. Compared with control rats, hepatic microsomes of GA rats exhibited the decreased formations of nor-CLZ and CLZ N-oxide, accompanied by decreases in activities of CYP2C11 and CYP2C19 and increased activity of CYP1A2. QT-PCR analysis demonstrated that GA enhanced expression of CYP1A2, but suppressed expression of CYP2C11 and CYP2C13. All these results support the conclusion that GA aggravated CLZ-induced hepatotoxicity, which was partly via inhibiting CYP2C11 and CYP2C13 or inducing CYP1A2.

A laboratory evaluation of the antibacterial and cytotoxic effect of Liquorice when used as root canal medicament.

AIM: To evaluate the antibacterial and cytotoxic effects of Liquorice as a root canal medicament and to compare its action to the commonly used root canal medicament calcium hydroxide Ca(OH)(2). METHODOLOGY: The antibacterial effect of Liquorice and Ca(OH)(2) either separately or in combination was investigated against Enterococcus faecalis. Agar-well diffusion methods, broth microdilution tests and biofilm susceptibility assays were used to determine the antibacterial activity. Human periodontal ligament fibroblast tissue culture was used to assess the cytotoxicity of the preparations under investigation. RESULTS: Liquorice extract either by itself or in combination with Ca(OH)(2) had a significant inhibitory effect against Enterococcus faecalis compared with that of Ca(OH)(2) alone. The use of Liquorice extract followed by Liquorice/Ca(OH)(2) mixture retained significantly more viable periodontal ligament cells than Ca(OH)(2) , which had a strong lethal effect on the cells. CONCLUSION: Liquorice extract either separately or as Liquorice/Ca(OH)(2) mixture had a potent bactericidal effect against Enterococcus faecalis and retained compatibility with fibroblasts in tissue culture compared to the commonly used root canal medicament Ca(OH)(2).

Synthesis and antitumour activity of glycyrrhetinic acid derivatives.

Glycyrrhetinic acid (GA) is one of many interesting triterpenoic acids showing anticancerogenic potential. GA is known to trigger apoptosis in tumour cell lines, although GA has a low cytotoxicity. In our study we were able to prepare derivatives of GA that show lowered the IC(50) values as determined by a sulforhodamine B (SRB) assay using 15 different human tumour cell lines. Thus, combining an ester group combined with the presence of an amino acid moiety led to a ca. 60-fold improved antitumor activity. Experiments on mouse embryonic fibroblasts (NiH3T3) revealed that these compounds showed a better selectivity for tumour cells compared to the parent compound GA. An apoptotic effect of some of these compounds was determined using an acridine orange/ethidium bromide (AO/EB) test and DNA laddering experiments.

Inhibiting hepatic gluconeogenesis by chitosan lactate nanoparticles containing CRTC2 siRNA targeted by poly(ethylene glycol)-glycyrrhetinic acid.

Diabetes mellitus is a chronic metabolic disorder characterized by insulin deficiency and impaired glucose metabolism. Overexpression of cAMP response element binding protein (CREB)-regulated transcriptional coactivator 2 (CRTC2) plays an important role in high gluconeogenesis in patients with diabetes type II. Using RNA interference technology for silencing CRTC2 gene expression could be helpful in controlling the level of blood glucose and gluconeogenesis. In this study, we designed a siRNA delivery platform comprising blended chitosan lactate (CT) and polyethylene glycol (PEG) conjugated with glycyrrhetinic acid (GA) for controlling gluconeogenesis. The nanoparticles showed spherical and smooth surface with ~ 189-nm size and + 5.1 zeta potential. Targeted nanoparticles were efficiently stable in serum and different levels of heparin media over 48 h. The gene knockdown efficiency of nanoparticles was comparable to Lipofectamine®, while they had no significant in vitro and in vivo toxicity. The in vivo therapeutic efficacy of targeted nanoparticles was also confirmed by reduced amount of fasting blood sugar in diabetic rat models. Furthermore, the nanoparticles were mostly accumulated in the liver after 2 h indicating the significant targeting ability of the prepared nanoparticles. Therefore, CT/PEG-GA nanoparticles can be considered as a potential candidate for targeted delivery of siRNA into hepatocytes in order to regulate gluconeogenesis in diabetes.

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-18ß-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 11ß-hydroxysteroid dehydrogenase (11ß-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.

Antitumor activities of novel glycyrrhetinic acid-modified curcumin-loaded cationic liposomes in vitro and in H22 tumor-bearing mice.

At present, the chemotherapy of advanced inoperable liver cancer is limited with serious side effects. Curcumin possesses multiple cancer preventive activities and low safety concerns. However, its poor solubility and instability in water pose significant pharmacological barriers to its clinical application. In this study, we presented a novel delivery system - the glycyrrhetinic acid modified curcumin-loaded cationic liposomes (GAMCLCL) and investigated its antitumor activities on HepG2 cells in vitro and in H22 tumor-bearing mice. The experimental results demonstrated that GAMCLCL was a cationic liposome and could be Intravenous administration. Compared to free curcumin, GAMCLCL exhibited stronger antitumor activities in vitro and in vivo. The antitumor results of GAMCLCL after intravenous administration were very similar to those after intratumoral administration. The main activities of GAMCLCL and curcumin included inhibition of HepG2 cell proliferation, inhibition of tumor growth, reduction of tumor microvascular density, down-regulation of the expression of VEGF protein, and up-regulation of the expression of Caspases3 protein in H22 tumor tissues. Furthermore, GAMCLCL improved the parameters of WBC, RBC, ALT, CRE, LDH of H22 tumor-bearing mice. Curcumin is a nontoxic natural compound with definite antitumor activities, its antitumor effects can be enhanced by preparation of GAMCLCL.

Final report on the safety assessment of Glycyrrhetinic Acid, Potassium Glycyrrhetinate, Disodium Succinoyl Glycyrrhetinate, Glyceryl Glycyrrhetinate, Glycyrrhetinyl Stearate, Stearyl Glycyrrhetinate, Glycyrrhizic Acid, Ammonium Glycyrrhizate, Dipotassium Glycyrrhizate, Disodium Glycyrrhizate, Trisodium Glycyrrhizate, Methyl Glycyrrhizate, and Potassium Glycyrrhizinate.

Glycyrrhetinic Acid and its salts and esters and Glycyrrhizic Acid and its salts and esters are cosmetic ingredients that function as flavoring agents or skin-conditioning agents - miscellaneous or both. These chemicals may be isolated from licorice plants. Glycyrrhetinc Acid is described as at least 98% pure, with 0.6% 24-OH-Glycyrrhetinic Acid, not more than 20 mu g/g of heavy metals and not more than 2 mu g/g of arsenic. Ammonium Glycyrrhizate has been found to be at least 98% pure and Dipotassium Glycyrrhizate has been found to be at least 95% pure. Glycyrrhetinic Acid is used in cosmetics at concentrations of up to 2%; Stearyl Glycyrrhetinate, up to 1%; Glycyrrhizic Acid, up to 0.1%; Ammonium Glycyrrhizate, up to 5%; Dipotassium Glycyrrhizate, up to 1%; and Potassium Glycyrretinate, up to 1%. Although Glycyrrhizic Acid is poorly absorbed by the intestinal tract, it may be hydrolyzed to Glycyrrhetinic Acid by a beta -glucuronidase produced by intestinal bacteria. Glycyrrhetinic Acid and Glycyrrhizic Acid bind to rat and human albumin, but do not absorb well into tissues. Glycyrrhetinic Acid and Glycyrrhizic Acid and metabolites are mostly excreted in the bile, with very little excreted in urine. Dipotassium Glycyrrhizate was undetectable in the receptor chamber when tested for transepidermal permeation through pig skin. Glycyrrhizic Acid increased the dermal penetration of diclofenac sodium in rat skin. Dipotassium Glycyrrhizate increased the intestinal absorption of calcitonin in rats. In humans, Glycyrrhetinic Acid potentiated the effects of hydrocortisone in the skin. Moderate chronic or high acute exposure to Glycyrrhizic Acid, Ammonium Glycyrrhizate, and their metabolites have been demonstrated to cause transient systemic alterations, including increased potassium excretion, sodium and water retention, body weight gain, alkalosis, suppression of the renin-angiotensis-aldosterone system, hypertension, and muscular paralysis; possibly through inhibition of 11beta -hydroxysteroid dehydrogenase-2 (11beta -OHSD2) in the kidney. Glycyrrhetinic Acid and its derivatives block gap junction intracellular communication in a dose-dependent manner in animal and human cells, including epithelial cells, fibroblasts, osteoblasts, hepatocytes, and astrocytes; at high concentrations, it is cytotoxic. Glycyrrhetinic Acid and Glycyrrhizic Acid protect liver tissue from carbon tetrachloride. Glycyrrhizic Acid has been used to treat chronic hepatitis, inhibiting the penetration of the hepatitis A virus into hepatocytes. Glycyrrhetinic Acid and Glycyrrhizic Acid have anti-inflammatory effects in rats and mice. The acute intraperitoneal LD(50) for Glycyrrhetinic Acid in mice was 308 mg/kg and the oral LD(50) was > 610 mg/kg. The oral LD(50) in rats was reported to be 610 mg/kg. Higher LD(50) values were generally reported for salts. Little short-term, subchronic, or chronic toxicity was seen in rats given ammonium, dipotassium, or disodium salts of Glycyrrhizic Acid. Glycyrrhetinic Acid was not irritating to shaved rabbit skin, but was considered slightly irritating in an in vitro test. Glycyrrhetinic Acid inhibited the mutagenic activity of benzo[a]pyrene and inhibited tumor initiation and promotion by other agents in mice. Glycyrrhizic Acid inhibited tumor initiation by another agent, but did not prevent tumor promotion in mice. Glycyrrhizic Acid delayed mortality in mice injected with Erlich ascites tumor cells, but did not reduce the mortality rate. Ammonium Glycyrrhizate was not genotoxic in in vivo and in vitro cytogenetics assays, the dominant lethal assay, an Ames assay, and heritable translocation tests, except for possible increase in dominant lethal mutations in rats given 2000 mg/kg day(-1) in their diet. Disodium Glycyrrhizate was not carcinogenic in mice in a drinking water study at exposure levels up to 12.2 mg/kg day(-1) for 96 weeks. Glycyrrhizate salts produced no reproductive or developmental toxicity in rats, mice, golden hamsters, or Dutch-belted rabbits, except for a dose-dependent increase (at 238.8 and 679.9 mg/kg day(-1)) in sternebral variants in a study using rats. Sedation, hypnosis, hypothermia, and respiratory depression were seen in mice given 1250 mg/kg Glycyrrhetinic Acid intraperitoneally. Rats fed a powdered diet containing up to 4% Ammonium Glycyrrhizate had no treatment related effects in motor function tests, but active avoidance was facilitated at 4%, unaffected at 3%, and depressed at 2%. In a study of 39 healthy volunteers, a no effect level of 2 mg/kg/day was determined for Glycyrrhizic Acid given orally for 8 weeks. Clinical tests in seven normal individuals given oral Ammonium Glycyrrhizate at 6 g/day for 3 days revealed reduced renal and thermal sweat excretion of Na+ and K+, but carbohydrate and protein metabolism were not affected. Glycyrrhetinic Acid at concentrations up to 6% was not a skin irritant or a sensitizer in clinical tests. Neither Glycyrrhizic Acid, Ammonium Glycyrrhizate, nor Dipotassium Glycyrrhizate at 5% were phototoxic agents or photosensitizers. Birth weight and maternal blood pressure were unrelated to the level of consumption of Glycyrrhizic Acid in 1049 Finnish women with infants, but babies whose mother consumed > 500 mg/wk were more likely to be born before 38 weeks. The Cosmetic Ingredient Review (CIR) Expert Panel noted that the ingredients in this safety assessment are not plant extracts, powders, or juices, but rather are specific chemical species that may be isolated from the licorice plant. Because these chemicals may be isolated from plant sources, however, steps should be taken to assure that pesticide and toxic metal residues are below acceptable levels. The Panel advised the industry that total polychlorobiphenyl (PCB)/pesticide contamination should be limited to not more than 40 ppm, with not more than 10 ppm for any specific residue, and that toxic metal levels must not contain more than 3 mg/kg of arsenic (as As), not more than 0.002% heavy metals, and not more than 1 mg/kg of lead (as Pb). Although the Panel noted that Glycyrrhizic Acid is cytotoxic at high doses and ingestion can have physiological effects, there is little acute, short-term, subchronic, or chronic toxicity and it is expected that these ingredients would be poorly absorbed through the skin. These ingredients are not considered to be irritants, sensitizers, phototoxic agents, or photosensitizers at the current maximum concentration of use. Accordingly, the CIR Expert Panel concluded that these ingredients are safe in the current practices of use and concentration. The Panel recognizes that certain ingredients in this group are reportedly used in a given product category, but the concentration of use is not available. For other ingredients in this group, information regarding use concentration for specific product categories is provided, but the number of such products is not known. In still other cases, an ingredient is not in current use, but may be used in the future. Although there are gaps in knowledge about product use, the overall information available on the types of products in which these ingredients are used and at what concentration indicate a pattern of use. Within this overall pattern of use, the Expert Panel considers all ingredients in this group to be safe.

Synthesis and Biological Evaluation of Glycyrrhetic Acid Derivatives as Potential VEGFR2 Inhibitors.

Vascular endothelial growth factor receptor 2 (VEGFR2) has been proven to play a major role in the regulation of tumor angiogenesis. A series of novel glycyrrhetic acid derivatives were synthesized and evaluated for their VEGFR2 inhibitory activity as well as their antiproliferative properties against four cancer cell lines (MCF-7, HeLa, HepG2, and A549). In vitro biological evaluations against these human tumor cell lines indicate that most of the prepared compounds have antiproliferative activities; compound 3 a (3ß-hydroxy-30-(4-phenyl-1-piperazinyl)olean-12-ene-11,30-dione) exhibited the best inhibitory activity against MCF-7 cells, with an IC50 value of 1.08 µm. Compound 3 a also showed the most potent inhibitory activity against VEGFR2 tyrosine kinase, with an IC50 value of 0.35 µm. Docking simulations were performed with the aim of discovering the binding mode of compound 3 a, and the results indicate that 3 a could bind at the VEGFR2 active site.

Free radical scavenging action of the natural polyamine spermine in rat liver mitochondria.

The isoflavonoid genistein, the cyclic triterpene glycyrrhetinic acid, and salicylate induce mitochondrial swelling and loss of membrane potential (Delta Psi) in rat liver mitochondria (RLM). These effects are Ca(2+)-dependent and are prevented by cyclosporin A and bongkrekik acid, classic inhibitors of mitochondrial permeability transition (MPT). This membrane permeabilization is also inhibited by N-ethylmaleimide, butylhydroxytoluene, and mannitol. The above-mentioned pro-oxidants also induce an increase in O(2) consumption and H(2)O(2) generation and the oxidation of sulfhydryl groups, glutathione, and pyridine nucleotides. All these observations are indicative of the induction of MPT mediated by oxidative stress. At concentrations similar to those present in the cell, spermine can prevent swelling and Delta Psi collapse, that is, MPT induction. Spermine, by acting as a free radical scavenger, in the absence of Ca(2+) inhibits H(2)O(2) production and maintains glutathione and sulfhydryl groups at normal reduced level, so that the critical thiols responsible for pore opening are also consequently prevented from being oxidized. Spermine also protects RLM under conditions of accentuated thiol and glutathione oxidation, lipid peroxidation, and protein oxidation, suggesting that its action takes place by scavenging the hydroxyl radical.

Liquorice and hypertension.

Glycyrrhetinic acid, the active constituent of liquorice, inhibits renal IIbeta-hydroxysteroid dehydrogenase. This allows cortisol to stimulate mineralocorticoid receptors, which can result in hypertension and hypokalaemia. Treatment options are based on pathophysiological understanding.

Severe hypokalaemic paralysis and rhabdomyolysis due to ingestion of liquorice.

Chronic ingestion of liquorice induces a syndrome with findings similar to those in primary hyperaldosteronism. We describe a patient who, with a plasma K+ of 1.8 mmol/l, showed a paralysis and severe rhabdomyolysis after the habitual consumption of natural liquorice. Liquorice has become widely available as a flavouring agent in foods and drugs. It is important for physicians to keep liquorice consumption in mind as a cause for hypokalaemic paralysis and rhabdomyolysis.

The old lady who liked liquorice: hypertension due to chronic intoxication in a memory-impaired patient.

The authors report an 85-year-old patient admitted because of cognitive impairment. During examination hypertension and hypokalaemia were found. After some time it was discovered that the patient was eating too much liquorice. The case demonstrates that liquorice intoxication should be considered as a cause of hypertension in old age. Furthermore the case demonstrates that missing an intoxication is a pitfall for medical history taking of patients with cognitive impairment.

Tumorigenicity study of disodium glycyrrhizinate administered orally to mice.

Disodium glycyrrhizinate (DG) was administered at concentrations of 0.15 (maximum tolerated dose), 0.08, 0.04 or 0% in the drinking-water to groups of 50, 70, 60 and 60 male B6C3F1 mice, respectively. Female groups, each consisting of 50 mice, were given DG in the drinking-water at concentrations of 0.3 (maximum tolerated dose), 0.15, 0.08 or 0%. Treatment was continued for 96 wk and the experiment was terminated at wk 110. There was no difference between treated and control groups in tumour incidence, in the latent period before tumours appeared or in the distribution of different types of tumour. Thus the long-term oral administration of DG to mice did not yield any evidence of chronic toxicity or tumorigenicity.

Teratogenicity study of ammonium glycyrrhizinate in the Sprague-Dawley rat.

Ammonium glycyrrhizinate (AG), a commercially used salt of glycyrrhizic acid, was administered in the drinking-water to Sprague-Dawley rats on days 7-17 of pregnancy. The actual intakes were 0, 21.33 +/- 1.22, 238.75 +/- 17.50 and 679.94 +/- 69.87 mg AG/kg body weight/day for groups 0, 1, 2 and 3, respectively. AG caused polydipsia in the dams. Foetuses from the treated litters did not present an increase in external malformations, a decrease in weight or a decrease in the degree of ossification. However, there was a slight but significant increase in embryolethality and in the prevalence of external haemorrhages. Skeletal examination revealed a dose-related increase in minor anomalies, especially in the sternebral variants. Renal ectopy also increased significantly at the highest dose. These results indicate that the possible embryotoxicity of aromatizing compounds should be considered.

[The toxicological characteristics of ammonium glycyrrhizinate (glycyram). A study of its acute and subacute toxicity]. / Toksikologicheskaia kharakteristika glitsirizinata ammoniia (glitsirama). Issledovanie ostroi i podostroi toksichnosti.

A single parenteral and oral administration of ammonium glycyrrhizinate in rat and mice experiments showed that the compound is related to practically nontoxic drugs. Its repeated administration (30 times) into the stomach in a maximum daily therapeutic dose (7 mg/kg) and in a four-fold dose (28 mg/kg) did not cause signs of intoxication, essential changes in the hematological and integral parameters, shifts in the activity of serum enzymes, morphological changes in the cell structures of the internal organs. Administration of the drug in a dose of 28 mg/kg for a second time led to changes in the activity of some enzymes in the brain, the development of parenchymatous dystrophy of the liver which changed to acidophilic necrosis attended with signs of regeneration. Under conditions of a subacute experiment the maximum daily therapeutic dose of ammonium glycyrrhizinate may be considered practically nontoxic.