Evaluation of the genotoxic potential of standardized extract of Glycyrrhiza glabra (GutGard™)

Mutagenicity and safety evaluation of Ashwagandha (Withania somnifera) root aqueous extract in different models

Withania somnifera (Ashwagandha) also called as Indian ginseng, a revered herb from Indian traditional system of medicine is a rejuvenator and tonic (Rasayana) used for its varied benefits. The roots of ashwagandha exhibit properties like anti-inflammatory, aphrodisiac, anthelmintic, astringent, diuretic, stimulant and thermogenic. However, data of ashwagandha on its mutagenic effects are lacking. In the present study, in-vitro genotoxicity tests were used to evaluate the mutagenic potential of Ashwagandha Root Extract (ARE). Concentrations of 0.156 to 5.00 mg/plate ARE were used for conducting Bacterial reverse mutation test (BRMT). For chromosome aberration (CA) test ARE was used in concentrations of 0.25 to 2.00 mg/ml, and for micronucleus (MN) tests ARE concentrations of 500/1000/2000 mg/kg were used. Acute oral toxicity was conducted in Wistar rats (n = 25) as per the OECD guideline (#423) with doses of 500/1000/2000 mg/kg body weight in male Swiss albino mice for morbidity and mortality for 3 days. The BRMT and CA tests were conducted with and without metabolic activation (S9). The study was approved by the institutional ethics committee (IEC) and institutional animal ethics committee (IAEC). ARE failed to show any mutagenic effects up to a dose of 5 mg/plate in BRMT. Also, ARE did not show any clastogenic activity in doses up to 2 mg/ml in CA test and in micronucleus test up to 2000 mg/kg body weight. These results were observed with and without metabolic activation (S9) under the stated experimental conditions. No mortality, morbidity, or any clinical signs were observed up to 3 days following ARE administration. Ashwagandha root extract failed to show any mortality in doses up to 2000 mg/kg oral dosage and did not show any mutagenic (genotoxic) effects in high concentrations.

Acute and Subchronic Toxicity Study of Flavonoid Rich Extract of Glycyrrhiza glabra (GutGard®) in Sprague Dawley Rats

Glycyrrhiza glabra (G. glabra) is well known for its health benefits based on the traditional and current scientific evidence. The aim of the present study was to evaluate the safety of GutGard, a standardised-flavonoid rich extract of G. glabra. The study was designed to evaluate the acute and subchronic oral toxicity of GutGard in Sprague Dawley rats according to the procedures and methods of Organisation for Economic Cooperation and Development (OECD) test guidelines for acute and subchronic toxicity. A single dose of GutGard at 5000 mg/kg body weight did not produce treatment related clinical signs of toxicity or mortality in any of the animals tested during the 14-day observation period. Therefore, the median lethal dose was estimated to be more than 5000 mg/kg. A subchronic oral toxicity study for 90 days in rats at the dose levels of 250, 500, and 1000 mg/kg did not show any treatment related adverse clinical signs. The treated animals exhibited normal weight gain and comparable feed intake. Ophthalmoscope examination did not reveal any abnormalities. Further, GutGard administration in rats did not show any clinical evidence of toxicity with respect to urinalysis, haematology, and blood chemistry parameters. The relative organ weight of vital organs did not differ significantly as compared to control. Gross and histopathological findings did not show any remarkable and treatment related changes. Based on the current experimental study findings, the median lethal dose (LD50) of GutGard was found to be >5000 mg/kg b.wt and the no observed adverse effect level (NOAEL) was found to be 1000 mg/kg rat b.wt.

A flavonoid rich standardized extract of Glycyrrhiza glabra protects intestinal epithelial barrier function and regulates the tight-junction proteins expression

BACKGROUND

Intestinal epithelial barrier dysfunction predisposes to many gastrointestinal, metabolic, and psychological disorders. A flavonoid rich extract of Glycyrrhiza glabra (FREG) has previously been reported to possess anti-inflammatory, antioxidant, and antiulcer properties.

AIM

To investigate the effect of FREG (GutGard^®) on restoring intestinal barrier function in tumor necrosis factor-alpha (TNF-α) stimulated human colonic adenocarcinoma cell monolayer (Caco-2) and 2,4,6-Trinitrobenzenesulfonic acid (TNBS) induced ulcerative colitis in rats.

METHODS

In in vitro, human intestinal Caco-2 cell monolayers were treated with TNF-α in the presence or absence of FREG and the paracellular permeability to FITC-conjugated 4-kD dextran (FD4) was measured to evaluate protection against the barrier dysfunction. In in vivo, intestinal barrier dysfunction was induced in male albino Wistar rats via intrarectal instillation of TNBS. Subsequently, the rats were treated orally with either FREG at 6.25, 12.5, and 25 mg/kg body weight, or Mesacol (250 mg/kg) for 5 days. On day 5, intestinal epithelial permeability was assessed with FD4 leakage into the serum. Also, colonic inflammation, colon morphology, histology and macroscopic score, weight to length ratio were evaluated. The activity of myeloperoxidase (MPO), TNF- α, secretory IgA levels and tight junction proteins expression were evaluated in rat's colon.

RESULTS

FREG protected the intestinal epithelial barrier integrity in human intestinal Caco-2 cells in vitro. FREG administration significantly improved the intestinal epithelial barrier function as evident from significant reduction in FD4 leakage. The colon morphology, histology score, macroscopic score, colon weight to length ratio also indicates beneficial effects of FREG on barrier function. In addition, FREG regulated the tight junction proteins, and markedly decreased TNF-α, MPO levels and significantly increased the secretory IgA levels in TNBS induced colitis rats.

CONCLUSION

The study findings support the protective action of FREG on intestinal epithelial barrier integrity indicating its potential in protecting from implications of leaky gut.

Toxicity as prime selection criterion among SARS-active herbal medications

We present here a new selection criterion for prioritizing research on efficacious drugs for the fight against COVID-19: the relative toxicity versus safety of herbal medications, which were effective against SARS in the 2002/2003 epidemic. We rank these medicines according to their toxicity versus safety as basis for preferential rapid research on their potential in the treatment of COVID-19. The data demonstrate that from toxicological information nothing speaks against immediate investigation on, followed by rapid implementation of Lonicera japonica, Morus alba, Forsythia suspensa, and Codonopsis spec. for treatment of COVID-19 patients. Glycyrrhiza spec. and Panax ginseng are ranked in second priority and ephedrine-free Herba Ephedrae extract in third priority (followed by several drugs in lower preferences). Rapid research on their efficacy in the therapy - as well as safety under the specific circumstances of COVID-19 - followed by equally rapid implementation will provide substantial advantages to Public Health including immediate availability, enlargement of medicinal possibilities, in cases where other means are not successful (non-responders), not tolerated (sensitive individuals) or just not available (as is presently the case) and thus minimize sufferings and save lives. Moreover, their moderate costs and convenient oral application are especially advantageous for underprivileged populations in developing countries.

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

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

Antimicrobial potential, phytochemical profile, cytotoxic and genotoxic screening of Sedum praealtum A. DC. (balsam)

BACKGROUND

Sedum praealtum has been used for a long time in traditional medicine as an analgesic and anti-inflammatory agent. Its beneficial effects have been known since ancient times, when Latinos used it to treat sore and swollen eyes. This research evaluated the antimicrobial potential, the cytotoxic and genotoxic effects, and some chromatographic profiles of the hydroethanolic extract of leaves, stems and roots of S. praealtum.

METHODS

The antimicrobial activities were carried out by broth microdilution and agar diffusion. In vitro cytotoxicity was evaluated by cell cultures of Aedes albopictus and the selectivity index (SI) was estimated: SI=CI50/MIC. Genotoxic and systemic toxic effects of S. praealtum leaves were analyzed by micronucleus assay in mice bone marrow. Chromatographic profiles and mass spectra were investigated by GC-MS.

RESULTS

Gram-positive (B. subtilis, B. cereus, M. luteus, E. faecalis and S. aureus) and gram-negative (E. coli, E. aerogenes, S. marcescens, P. aeruginosa, P. mirabilis and S. typhimurium) bacteria exhibited MICs ranging from 12.5-50 and 0-50 mg/ml, respectively. Sedum praealtum showed no efficacy against M. tuberculosis and M. bovis. Cytotoxicity (CI50) of S. praealtum was 4.22 and 5.96 mg/ml for leaves and stems, respectively, while its roots showed no cytotoxicity. Micronucleated polychromatic erythrocytes (MNPCEs) analyzes showed no differences between treatment doses (0.5-2 g/kg) and negative control (NaCl), but the PCE/NCE ratio (polychromatic erythrocyte/normochromatic erythrocyte) showed significant differences. Phytochemical screening identified thirteen compounds in the leaves, stems and roots of S. praealtum potentially associated with their biological activities.

CONCLUSIONS

This research comprises a first scientific study on genotoxicity, cytotoxicity and antimicrobial effects of S. praealtum (Balsam), and it provides an initial theoretical foundation for its comprehensive use. Results showed antibacterial action of S. praealtum against gram-positive bacteria and some gram-negative species (depending on the plant anatomical part), but ineffective antimycobacterial action. However, S. praealtum leaves and stems display potential cytotoxicity, contributing to the SI < 1 values. In addition, S. praealtum leaves exhibit no clastogenic and/or aneugenic effects, but it has systemic toxicity dose-independent.

Mutagenicity and Acute Oral Toxicity Test for Herbal Poultry Feed Supplements

Herbal products are being used and trusted globally for thousands of years for their health benefits and limited side effects. Globally, a general belief amongst the consumers is that herbal supplements are always safe because they are “natural.” But later, research reveals that they may not be safe. This raises concern on their safety and implications for their use as feed supplement or medicine. Toxicity testing can reveal some of the risks that may be associated with use of herbs, therefore avoiding potential harmful effects. The present study was designed to investigate five poultry feed supplements (PFS), EGMAX® (to revitalize ovarian activity), FEED-X™ (feed efficiency enhancer), KOLIN PLUS™ (natural replacer of synthetic choline chloride), PHYTOCEE® (natural defence enhancer), and STODI® (to prevent and control loose droppings), for their possible mutagenicity and toxicity. Bacterial reverse mutation (BRMT) and acute oral toxicity tests were employed to assess the PFS for their possible mutagenicity and toxicity. Results indicated that the PFS were devoid of mutagenic effects in BRMT and showed higher safety profile in rodent acute oral toxicity test.

A New Series of Pyrrole-Based Chalcones: Synthesis and Evaluation of Antimicrobial Activity, Cytotoxicity, and Genotoxicity

In an effort to develop new potent antimicrobial and anticancer agents, new pyrrole-based chalcones were designed and synthesized via the base-catalyzed Claisen-Schmidt condensation of 2-acetyl-1-methylpyrrole with 5-(aryl)furfural derivatives. The compounds were evaluated for their in vitro antimicrobial effects on pathogenic bacteria and Candida species using microdilution and ATP luminescence microbial cell viability assays. MTT assay was performed to determine the cytotoxic effects of the compounds on A549 human lung adenocarcinoma, HepG2 human hepatocellular carcinoma, C6 rat glioma, and NIH/3T3 mouse embryonic fibroblast cell lines. 1-(1-Methyl-1H-pyrrol-2-yl)-3-(5-(4-chlorophenyl)furan-2-yl)prop-2-en-1-one (7) and 1-(1-methyl-1H-pyrrol-2-yl)-3-(5-(2,5-dichlorophenyl)furan-2-yl)prop-2-en-1-one (9) were found to be the most potent antifungal agents against Candida krusei and therefore these compounds were chosen for flow cytometry analysis and Ames MPF assay. ATP bioluminescence assay indicated that the antifungal activity of compounds 7 and 9 against C. krusei was significantly higher than that of other compounds and the reference drug (ketoconazole), whereas flow cytometry analysis revealed that the percentage of dead cells treated with compound 7 was more than that treated with compound 9 and ketoconazole. According to Ames MPF assay, compounds 7 and 9 were found to be non-genotoxic against TA98 and TA100 with/without metabolic activation. MTT assay indicated that 1-(1-methyl-1H-pyrrol-2-yl)-3-(5-(2-nitrophenyl)furan-2-yl)prop-2-en-1-one (3) showed more selective anticancer activity than cisplatin against the HepG2 cell line. On the other hand, 1-(1-methyl-1H-pyrrol-2-yl)-3-(5-(4-nitrophenyl)furan-2-yl)prop-2-en-1-one (1) was found to be more effective and selective on the A549 cell line than cisplatin.

Pharmacological and Toxicological Screening of Novel Benzimidazole-Morpholine Derivatives as Dual-Acting Inhibitors

The aim of this study was to investigate acetylcholinesterase (AChE), monoamine oxidase A (MAO-A), monoamine oxidase B (MAO-B), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzyme inhibitory, and antimicrobial activities of a new series of 2-(4-substituted phenyl)-1-[2-(morpholin-4-yl)ethyl]-1H-benzimidazole derivatives, for their possible use as multi-action therapeutic agents. Target compounds (n = 15) were synthesized under microwave irradiation conditions in two steps, and their structures were elucidated by FT-IR, ¹H-NMR, ¹³C-NMR and high resolution mass spectroscopic analyses. Pharmacological screening studies revealed that two of the compounds (2b and 2j) have inhibitory potential on both COX-1 and COX-2 enzymes. In addition, cytotoxic and genotoxic properties of the compounds 2b, 2j and 2m were investigated via the well-known MTT and Ames tests, which revealed that the mentioned compounds are non-cytotoxic and non-genotoxic. As a concise conclusion, two novel compounds were characterized as potential candidates for treatment of frequently encountered inflammatory diseases.

Toxicological Effects of Glycyrrhiza glabra (Licorice): A Review

Licorice (Glycyrrhiza glabra) has been considered as an herbal drug since ancient time. Nowadays, it is a well-known spice that possesses worth pharmacological effects. However, some relevant articles have revealed negative impacts of licorice in health. By considering the great wishes in using herbal medicine, it is important to show adverse effects of herbal medicine in health. At present, there are misunderstandings toward the safety of herbal medicines. Herein, we gathered scientific research projects on the toxicity effects of licorice and glycyrrhizin to highlight their safety. In this regards, we categorized our findings about the toxicity effects of licorice and glycyrrhizin in acute, sub-acute, sub-chronic, and chronic states. Besides, we discussed on the cytotoxicity, genotoxicity, mutagenicity, and carcinogenicity of licorice and glycyrrhizin as well as their developmental toxicity. This review disclosed that G. glabra and glycyrrhizin salts are moderately toxic. They need to be used with caution during pregnancy. G. glabra and glycyrrhizin possess selective cytotoxic effects on cancerous cells. The most important side effects of licorice and glycyrrhizin are hypertension and hypokalemic-induced secondary disorders. Licorice side effects are increased by hypokalemia, prolonged gastrointestinal transient time, decreased type 2 11-beta-hydroxysteroid dehydrogenase activities, hypertension, anorexia nervosa, old age, and female sex. Copyright © 2017 John Wiley & Sons, Ltd.

Economic Importance

The beneficial effects of liquorice in treating chills, colds, and coughs have been fully discussed in Ayurveda, as well as in the texts of ancient Egyptians, Greeks, and Romans. The plant has been prescribed for dropsy during the period of famous Hippocrates. The reason being that it was quite helpful as thirst-quenching drugs (Biondi et al. in J Nat Prod 68:1099–1102, 2005; Mamedov and Egamberdieva in Herbals and human health-phytochemistry. Springer Nature Publishers, 41 pp, 2017). No doubt, the clinical use of liquorice in modern medicine started around 1930; Pedanios Dioscorides of Anazarba (Adana), first century AD-Father of Pharmacists, mentions that it is highly effective in the treatment of stomach and intestinal ulcers. In Ayurveda, people in ancient Hindu culture have used it for improving sexual vigor.

Glycyrrhiza glabra

Liquorice foliage

Evaluation of the mutagenicity and antimutagenicity of Ziziphus joazeiro Mart. bark in the micronucleus assay

The aim of this study was to evaluate the mutagenicity (clastogenicity/aneugenicity) of a glycolic extract of Ziziphus joazeiro bark (GEZJ) by the micronucleus assay in mice bone marrow. Antimutagenic activity was also assessed using treatments associated with GEZJ and doxorubicin (DXR). Mice were evaluated 24–48 h after exposure to positive (N-nitroso-N-ethylurea, NEU - 50 mg.kg⁻¹ and DXR - 5 mg.kg⁻¹) and negative (150 mM NaCl) controls, as well as treatment with GEZJ (0.5–2 g.kg⁻¹), GEZJ (2 g.kg⁻¹) + NEU and GEZJ (2 g.kg⁻¹) + DXR. There were no significant differences in the frequencies of micronucleated polychromatic erythrocytes in mice treated with GEJZ and GEJZ + DXR compared to the negative controls, indicating that GEZJ was not mutagenic. Analysis of the polychromatic:normochromatic erythrocyte ratio revealed significant differences in the responses to doses of 0.5 g.kg⁻¹ and 1–2 g.kg⁻¹ and the positive control (NEU). These results indicated no systemic toxicity and moderate toxicity at lower and higher doses of GEZJ. The lack of mutagenicity and systemic toxicity in the antimutagenic assays, especially for treatment with GEZJ + DXR, suggested that phytochemical compounds in Z. joazeiro bark attenuated DXR-induced mutagenicity and the moderate systemic toxicity of a high dose of Z. joazeiro bark (2 g.kg⁻¹). Further studies on the genotoxicity of Z. joazeiro extracts are necessary to establish the possible health risk in humans and to determine the potential as a chemopreventive agent for therapeutic use.

Anti-Helicobacter pylori Properties of GutGard™

Presence of Helicobacter pylori is associated with an increased risk of developing upper gastrointestinal tract diseases. Antibiotic therapy and a combination of two or three drugs have been widely used to eradicate H. pylori infections. Due to antibiotic resistant drugs, new drug resources are needed such as plants which contain antibacterial compounds. The aim of this study was to investigate the ability of GutGard™ to inhibit H. pylori growth both in Mongolian gerbils and C57BL/6 mouse models. Male Mongolian gerbils were infected with the bacteria by intragastric inoculation (2×10⁹ CFU/gerbil) 3 times over 5 days and then orally treated once daily 6 times/week for 8 weeks with 15, 30 and 60 mg/kg GutGard™. After the final administration, biopsy samples of the gastric mucosa were assayed for bacterial identification via urease, catalase and ELISA assays as well as immunohistochemistry (IHC). In the Mongolian gerbil model, IHC and ELISA assays revealed that GutGard™ inhibited H. pylori colonization in gastric mucosa in a dose dependent manner. The anti-H. pylori effects of GutGard™ in H. pylori-infected C57BL/6 mice were also examined. We found that treatment with 25 mg/kg GutGard™ significantly reduced H. pylori colonization in mice gastric mucosa. Our results suggest that GutGard™ may be useful as an agent to prevent H. pylori infection.

In vitro studies on protective effect of Glycyrrhiza glabra root extracts against cadmium-induced genetic and oxidative damage in human lymphocytes

Cadmium is a modern environmental contaminant that is toxic and carcinogenic. Glycyrrhiza glabra is a traditional medicinal herb which grows in the various parts of the World. Recent studies demonstrated that G. glabra has antifungal, antimicrobial, antioxidant, and powerful antiinflammatory features. The purpose of this study was to investigate the genetic safety of extracts from G. glabra and its effects on cadmium (as CdCl2) induced genotoxicity. Therefore we evaluated the capability of G. glabra extract to inhibit the rate of micronucleus (MN), sister chromatid exchange (SCE) formations induced by CdCl2. Moreover, to assess the effects of G. glabra on cell viability and oxidative status, we performed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and total antioxidant capacity (TAC) assays. Our results showed that there were significant increases (P < 0.05) in both SCE and MN frequencies of cultures treated with CdCl2 (5 ppm) as compared to controls. However, co-application of G. glabra extract (5, 10 and 20 ppm) and CdCl2 resulted in decreases of MN and SCE rates as compared to the group treated with CdCl2 alone. Again, the results of MTT and TAC assays clearly indicated dose dependent ameliorative effects of G. glabra extracts against CdCl2 toxicity. In conclusion, this study demonstrated for the first time that G. glabra extracts provided increased resistance of DNA against CdCl2 induced genetic and oxidative damage in human lymphocytes. So, the risk on target tissues of CdCl2 could be reduced and ensured early recovery from its toxicity.

Safety evaluation of turmeric polysaccharide extract: assessment of mutagenicity and acute oral toxicity

Curcuma longa Linn. (Zingiberaceae) commonly known as turmeric has long been used for centuries as a spice and household remedy. The present study was carried out to assess the possible mutagenic potential and acute oral toxicity of polysaccharide extract of turmeric rhizome (NR-INF-02) using standard tests. The standard battery of in vitro genotoxicity tests, bacterial reverse mutation test (BRMT), chromosome aberration (CA), and micronucleus (MN) tests were employed to assess the possible mutagenic activity of NR-INF-02 (Turmacin). The results showed no mutagenic effect with NR-INF-02 up to a dose of 5000 µg/mL in BRMT. The results on CA and MN tests revealed the non clastogenic activity of NR-INF-02 in a dose range of 250.36 to 2500 µg/mL with and without metabolic activation (S9). In acute oral toxicity study, NR-INF-02 was found to be safe up to 5 g/kg body weight in Wistar rats. Overall, results indicated that polysaccharide extract of C. longa was found to be genotoxically safe and also exhibited maximum tolerable dose of more than 5 g/kg rat body weight.

Effect of GutGard in the Management of Helicobacter pylori: A Randomized Double Blind Placebo Controlled Study

A randomized, double blind placebo controlled study was conducted to evaluate the efficacy of GutGard (root extract of Glycyrrhiza glabra) in the management of Helicobacter pylori (H. pylori) gastric load. Participants diagnosed with H. pylori infection were randomly assigned to two groups to orally receive 150 mg of GutGard (n = 55) or placebo (n = 52) once daily for 60 days. H. pylori infection was assessed using (13)C-urea breath test ((13)C-UBT) at days 0, 30, and 60. Stool Antigen test (HpSA) was also performed on days 0, 30, and 60. Repeated measures of analysis of variance (RMANOVA), chi-square, and Fisher's exact probability tests were used to compare the treatment outcomes. A significant interaction effect between group and time (P = 0.00) and significant difference in mean Delta Over Baseline (DOB) values between GutGard (n = 50) and placebo (n = 50) treated groups after intervention period were observed. On day 60, the results of HpSA test were negative in 28 subjects (56%) in GutGard treated group whereas in placebo treated group only 2 subjects (4%) showed negative response; the difference between the groups was statistically significant. On day 60, the results of (13)C-UBT were negative in 24 (48%) in GutGard treated group and the difference between the groups was statistically significant. The findings suggest GutGard is effective in the management of H. pylori.

Evaluation of the mutagenic potential and acute oral toxicity of standardized extract of Ocimum sanctum (OciBest™)

Ocimum sanctum L. (Lamiaceae) is found throughout India and in many parts of world. O. sanctum is used for the treatment of various health indications. In this lieu, it is of prime importance to investigate the safety aspects of the plant. Hence, the present study was conducted to investigate the possible genotoxic potential and acute oral toxicity of the extract of O. sanctum (OciBest™). The standard battery of in vitro genotoxicity tests, namely bacterial reverse mutation, chromosome aberration and micronucleus (MN) tests were employed to assess the possible mutagenic activity. The results showed that OciBest™ (7.9-2500.0 µg/mL) did not increase the number of histidine revertant colonies in Salmonella typhimurium strains (TA98 and TAMix) with and without exogenous metabolic activation (S9). OciBest™ (10.0-100.0 µg/mL) did not show structural chromosomal aberrations or increase in MN induction, with and without S9, at the tested dose range in both 4-h and 18-h exposure cell cultures. Thus, OciBest™ is not genotoxic in bacterial reverse mutation, chromosomal aberration and MN tests. In an acute oral toxicity test, rats were treated with 5 g/kg of OciBest™ and observed for signs of toxicity for 14 days and the results did not show any treatment-related toxic effects to Wistar rats.

In vitro anti-Helicobacter pylori activity of a flavonoid rich extract of Glycyrrhiza glabra and its probable mechanisms of action

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza glabra Linn. is regarded useful for peptic ulcer in traditional systems of medicine in India and Helicobacter pylori has been considered as one of the causative factors for peptic ulcer. Aim of the present study is to evaluate the anti-Helicobacter pylori action of GutGard(®), a flavonoid rich extract of Glycyrrhiza glabra and further to elucidate the possible mechanisms of its anti-Helicobacter pylori action.

MATERIALS AND METHODS

Agar dilution and microbroth dilution methods were used to determine the minimum inhibitory concentration of GutGard(®) against Helicobacter pylori. Protein synthesis, DNA gyrase, dihydrofolate reductase assays and anti-adhesion assay in human gastric mucosal cell line were performed to understand the mechanisms of anti-Helicobacter pylori activity of GutGard(®).

RESULTS

GutGard(®) exhibited anti-Helicobacter pylori activity in both agar dilution and microbroth dilution methods. Glabridin, the major flavonoid present in GutGard(®) exhibited superior activity against Helicobacter pylori while glycyrrhizin did not show activity even at 250 μg/ml concentration. In protein synthesis assay, GutGard(®) showed a significant time dependent inhibition as witnessed by the reduction in (35)S methionine incorporation into Helicobacter pylori ATCC 700392 strain. Additionally, GutGard(®) showed a potent inhibitory effect on DNA gyrase and dihydrofolate reductase with IC(50) value of 4.40 μg/ml and 3.33 μg/ml respectively. However, the extract did not show significant inhibition on the adhesion of Helicobacter pylori to human gastric mucosal cell line at the tested concentrations.

CONCLUSION

The present study shows that, GutGard(®) acts against Helicobacter pylori possibly by inhibiting protein synthesis, DNA gyrase and dihydrofolate reductase.