A new paradigm in threshold of toxicological concern based on chemoinformatics analysis of a highly curated database enriched with antimicrobials.

A new database of antimicrobial-enriched chemicals for the Threshold of Toxicological Concern (TTC) approach has been compiled, comprising 1357 chemicals with 276, 54, and 1027 substances in Cramer Classes I, II, and III, respectively. To enrich the chemical space of the No-/Lowest-Observed-Adverse Effect Level (NOAEL/LOAEL) database, a reference Antimicrobial (AM) Inventory (681) was established for chemical inclusion. To this database, the three existing TTC datasets were combined via robust data fusion process. From the final AM TTC Dataset, the fifth percentiles were derived to be 2.7, 0.43, and 0.12 mg/kg-bw/day for Cramer Classes I, II, and III, respectively. Considering the high percentage of AMs being Cramer Class III, the thresholds are remarkably stable across various TTC datasets. Based on the AM-enriched database, a set of AM categories stratified across potency were developed to classify AMs beyond the capability of the conventional Cramer Tree approach. Grouping the query chemical within the AM category, further distribution analyses were conducted to identify subclasses and differentiate potency. This study proposes a new framework for potential assessment of chronic toxicity made possible with the power of modern reliable databases and chemoinformatic methods.

Trans-3,5-dicaffeoylquinic acid from Geigeria alata Benth. & Hook.f. ex Oliv. & Hiern with beneficial effects on experimental diabetes in animal model of essential hypertension.

Geigeria alata Benth. & Hook.f. ex Oliv. & Hiern (Asteraceae) is used in Sudanese folk medicine for treatment of diabetes. The study aimed to estimate the acute oral toxicity of trans-3,5-dicaffeoylquinic acid (3,5-diCQA) from G. alata roots and to assess its antihypeglycemic, antioxidant and antihypertensive effects on chemically-induced diabetic spontaneously hypertensive rats (SHRs). The structure of 3,5-diCQA was established by NMR and HRMS spectra. Type 2 diabetes was induced by intraperitoneal injection of streptozotocin. 3,5-diCQA was slightly toxic with LD50 = 2154 mg/kg. At 5 mg/kg 3,5-diCQA reduced significantly (p < 0.05) the blood glucose levels by 42%, decreased the blood pressure by 22% and ameliorated the oxidative stress biomarkers reduced glutathione, malondialdehyde, and serum biochemical parameters. The beneficial effect on antioxidant enzymes was evidenced by the elevated glutathione peroxidase, glutathione reductase, and glutathione S-transferase activitiy in the livers of diabetic animals. 3,5-diCQA prevents the histopathological changes related to diabetes and hypertension. 3,5-diCQA was more potent α-glucosidase inhibitor (IC50 27.24 µg/mL) than acarbose (IC50 99.77 µg/mL). The antihyperglycemic action of the compound was attributed to the α-glucosidase inhibition. The beneficial effects of 3,5-diCQA on streptozotocin-induced diabetic hypertensive rats support the traditional use of G.alata for the management of diabetes.

Micellar propolis nanoformulation of high antioxidant and hepatoprotective activity

ABSTRACT The present study reports a promising antioxidant protection by a recently developed micellar propolis formulation, against oxidative stress in in vitro and in vivo models of toxicity. The formulation, based on poplar propolis encapsulated in poly(ethylene oxide)-β-poly(propylene oxide)-β-poly(ethylene oxide) triblock copolymer (PEO26-PPO40-PEO26) micelles is characterized by small size (D h = 20 nm), enhances aqueous solubility and good colloidal stability. In vitro, propolis-loaded PEO26-PPO40-PEO26 micelles (20-100 µg/ml) significantly increased the cell viability of human hepatoma HepG2 cells, subjected to H2O2-induced cell injury (0.1 mM, 1 h). Antioxidant activity and protection of the micellar propolis were evaluated in a model of carbon tetrachloride-induced hepatotoxicity in rats (10% CCl4 solution, 1.25 ml/kg, p.o.) by measurement of non-enzyme (malondialdehyde and glutathione) and enzyme (catalase and superoxide dismutase) biomarkers of oxidative stress. Clinic observations, hematological, biochemical parameters and histological analysis were also performed. In vivo, micellar propolis (20 mg/kg b.w., p.o., 14 days) ameliorated CCl4-induced acute liver injury in rats. The oral administration of micellar propolis significantly prevented serum transaminase increases, as well as brought the levels of malondialdehyde, glutathione, and antioxidant enzymes catalase and superoxide dismutase toward the controls levels. Therefore, PEO26-PPO40-PEO26 micelles could be considered as a promising oral delivery system of propolis against oxidative stress injury in liver cells.

Molecular Modeling Approach to Study the PPARγ-Ligand Interactions.

The chapter is focused on methods relevant for predictive toxicology and computer-aided drug design (adverse outcome pathway development, pharmacophore modeling, docking, and 3D QSAR analysis) and applied to study interactions between peroxisome proliferator-activated receptor γ (PPARγ) and its ligands. The methods have been combined to develop an integrated in silico approach allowing both to predict potential PPARγ-mediated hepatotoxicity of receptor's full agonists, thus supporting hazard characterization, and to identify naturally derived antidiabetic triterpenoids potentially acting through PPARγ partial agonism.

In silico and in vivo studies of Astragalus glycyphylloides saponin(s) with relevance to metabolic syndrome modulation.

Triterpenoids are well known modulators of metabolic syndrome. One of the suggested modes of action (MoAs) involves peroxisome proliferator-activated receptor gamma (PPARγ) binding. In this study we aimed to: (i) evaluate in silico potential metabolites and PPARγ-mediated MoA of the sapogenin of the main saponin present in a purified saponins' mixture (PSM) from Astragalus glycyphylloides; (ii) estimate in silico and in vivo PSM's toxicity; and (iii) investigate in vivo antihyperglycaemic, hypolipidaemic, antioxidant and hepatoprotective effects of PSM. Metabolites and toxicity were predicted using Meteor and Derek Nexus expert systems (Lhasa Limited) and PPARγ binding was investigated using the software MOE (CCG Inc.). PSM's acute oral toxicity was evaluated in mice and the pharmacological effects were assessed in streptozotocin-induced diabetic spontaneously hypertensive rats (SHRs). Liver histopathology was studied as well. PPARγ weak partial agonism was predicted in silico for 24 probable/plausible Phase I metabolites which docking poses were clustered in 12 different binding modes with characteristic protein-ligand interactions. PSM's beneficial effects on the levels of blood glucose, triglycerides, and total cholesterol, on oxidative stress markers and liver histology in diabetic SHRs were comparable to those of the PPARγ ligand pioglitazone. PSM's safety profile was confirmed in silico and in vivo.

Alcesefoliside protects against oxidative brain injury in rats

ABSTRACT This study investigated the possible antioxidant and neuroprotective effects of alcesefoliside, isolated from Astragalus monspessulanus L., Fabaceae, against carbon tetrachloride (CCl4)-induced brain injury in Wistar rats. Iron sulphate/ascorbic acid lipid peroxidation was induced in rat brain microsomes and pre-incubated with alcesefoliside and silybin. Male rats were treated in vivo with alcesefoliside and with silymarin alone; animals challenged with CCl4; and pre-treated with alcesefoliside or silymarin in respective doses for 7 days, challenged with CCl4, followed by curative treatment (additional 14 days). The activity of acetylcholine esterase and the antioxidant enzymes: superoxide-dismutase, catalase, glutathione-peroxidase, glutathione reductase and glutathione-S-transferase as well as the biomarkers of oxidative stress malondialdehyde and reduced glutathione were measured. The alcesefoliside pre-treatment and consecutive curative treatment normalizes the activity of the antioxidant enzymes as well as levels of malondialdehyde and reduced glutathione. The observed effects on tissue level correlate with the histopathological observations of the brain. They were comparable to the effects of silymarin, used as a positive control. The results showed that alcesefoliside has a neuroprotective effect against CCl4-induced brain toxicity in rats.

In vitro/in vivo antioxidant and hepatoprotective potential of defatted extract and flavonoids isolated from Astragalus spruneri Boiss. (Fabaceae).

The aim of the current study was to evaluate the effect of a defatted extract (EAS) and three flavonoids, isolated from Astragalus spruneri Boiss. (Fabaceae) using in vitro/in vivo models of liver injury. The EAS was characterized by HPLC and flavonoids (14 mg/g dw) and saponins (8 mg/g dw) were proved. The flavonoids (ASF1, ASF3 and ASF5) were isolated from the same extract and partially identified by LC-MS. In in vitro models of non-enzyme induced (Fe2+/AA) lipid peroxidation in isolated liver microsomes and CCl4-induced metabolic bioactivation and t-BuOOH-induced oxidative stress in isolated rat hepatocytes, both EAS and the flavonoids exerted similar to silybin (positive control) an antioxidant and cytoprotective activity, discerned by decreased MDA production in the microsomes and by preserved cell viability and GSH levels as well as by decreased LDH activity and MDA quantity in isolated rat hepatocytes. The antioxidant and hepatoprotective effect of EAS has been confirmed in vivo against CCl4-induced liver injury in rats. EAS restored the GSH levels and the activity of the antioxidant enzymes CAT and SOD, affected by CCl4 administration, as well as decreased the production of MDA. The effect of EAS was commensurable with those of silymarin.

Molecular determinants of PPARγ partial agonism and related in silico/in vivo studies of natural saponins as potential type 2 diabetes modulators.

The metabolic syndrome, which includes hypertension, type 2 diabetes (T2D) and obesity, has reached an epidemic-like scale. Saponins and sapogenins are considered as valuable natural products for ameliorating this pathology, possibly through the nuclear receptor PPARγ activation. The aims of this study were: to look for in vivo antidiabetic effects of a purified saponins' mixture (PSM) from Astragalus corniculatus Bieb; to reveal by in silico methods the molecular determinants of PPARγ partial agonism, and to investigate the potential PPARγ participation in the PSM effects. In the in vivo experiments spontaneously hypertensive rats (SHRs) with induced T2D were treated with PSM or pioglitazone as a referent PPARγ full agonist, and pathology-relevant biochemical markers were analysed. The results provided details on the PSM modulation of the glucose homeostasis and its potential mechanism. The in silico studies focused on analysis of the protein-ligand interactions in crystal structures of human PPARγ-partial agonist complexes, pharmacophore modelling and molecular docking. They outlined key pharmacophoric features, typical for the PPARγ partial agonists, which were used for pharmacophore-based docking of the main PSM sapogenin. The in silico studies, strongly suggest possible involvement of PPARγ-mediated mechanisms in the in vivo antidiabetic and antioxidant effects of PSM from A. corniculatus.

Natural modulators of nonalcoholic fatty liver disease: Mode of action analysis and in silico ADME-Tox prediction.

Nonalcoholic fatty liver disease (NAFLD) is considered to be the most common chronic liver disease. The discovery of natural product-based NAFLD modulators requires a more comprehensive study of their modes of action (MoAs). In this study we analysed available in the literature data for 26 naturally-derived compounds associated with experimental evidence for NAFLD alleviation and outlined potential biomolecular targets and a network of pharmacological MoAs for 12 compounds with the highest number of experimentally supported MoA key events, modulated by them. Despite the general perception that the therapeutic agents of natural origin are safe, an evaluation of ADME-Tox properties of these compounds has also been performed in order to estimate their suitability as drug candidates. We evaluated how the investigated structures fit to Lipinski's "Rule of five" and predicted their potential Phase I biotransformation pathways and toxicological effects using the ACD/Percepta platform, and the Meteor Nexus and Derek Nexus knowledge-based systems. Our results revealed the potential of the studied compounds as lead structures and outlined those of them that needed further optimisation of their pharmacokinetic profiles. The presented combined MoA/in silico approach could be extrapolated to naturally-derived and pathology-relevant lead structures with other biological activities. It could direct their optimisation by a mechanistically justified in silico evaluation.

Thresholds of Toxicological Concern for cosmetics-related substances: New database, thresholds, and enrichment of chemical space.

A new dataset of cosmetics-related chemicals for the Threshold of Toxicological Concern (TTC) approach has been compiled, comprising 552 chemicals with 219, 40, and 293 chemicals in Cramer Classes I, II, and III, respectively. Data were integrated and curated to create a database of No-/Lowest-Observed-Adverse-Effect Level (NOAEL/LOAEL) values, from which the final COSMOS TTC dataset was developed. Criteria for study inclusion and NOAEL decisions were defined, and rigorous quality control was performed for study details and assignment of Cramer classes. From the final COSMOS TTC dataset, human exposure thresholds of 42 and 7.9 µg/kg-bw/day were derived for Cramer Classes I and III, respectively. The size of Cramer Class II was insufficient for derivation of a TTC value. The COSMOS TTC dataset was then federated with the dataset of Munro and colleagues, previously published in 1996, after updating the latter using the quality control processes for this project. This federated dataset expands the chemical space and provides more robust thresholds. The 966 substances in the federated database comprise 245, 49 and 672 chemicals in Cramer Classes I, II and III, respectively. The corresponding TTC values of 46, 6.2 and 2.3 µg/kg-bw/day are broadly similar to those of the original Munro dataset.

The application of molecular modelling in the safety assessment of chemicals: A case study on ligand-dependent PPARγ dysregulation.

The aim of this paper was to provide a proof of concept demonstrating that molecular modelling methodologies can be employed as a part of an integrated strategy to support toxicity prediction consistent with the mode of action/adverse outcome pathway (MoA/AOP) framework. To illustrate the role of molecular modelling in predictive toxicology, a case study was undertaken in which molecular modelling methodologies were employed to predict the activation of the peroxisome proliferator-activated nuclear receptor γ (PPARγ) as a potential molecular initiating event (MIE) for liver steatosis. A stepwise procedure combining different in silico approaches (virtual screening based on docking and pharmacophore filtering, and molecular field analysis) was developed to screen for PPARγ full agonists and to predict their transactivation activity (EC50). The performance metrics of the classification model to predict PPARγ full agonists were balanced accuracy=81%, sensitivity=85% and specificity=76%. The 3D QSAR model developed to predict EC50 of PPARγ full agonists had the following statistical parameters: q2cv=0.610, Nopt=7, SEPcv=0.505, r2pr=0.552. To support the linkage of PPARγ agonism predictions to prosteatotic potential, molecular modelling was combined with independently performed mechanistic mining of available in vivo toxicity data followed by ToxPrint chemotypes analysis. The approaches investigated demonstrated a potential to predict the MIE, to facilitate the process of MoA/AOP elaboration, to increase the scientific confidence in AOP, and to become a basis for 3D chemotype development.

Hepatoprotective and antioxidant potential of Asphodeline lutea (L.) Rchb. roots extract in experimental models in vitro/in vivo.

The aim of this study was to investigate the effect of Asphodeline lutea (L.) Rchb. dry root extract (ALE) administered alone and against carbon tetrachloride (CCl4)-induced liver injury in vitro/in vivo. The dried roots of A. lutea were extracted with 70% ethanol and was characterized with HPLC-UV. Hepatoprotective potential was investigated by in vivo/in vitro assays in Wistar rats as well as antioxidant properties. At concentrations ranging from 10 to 200µg/mL of ALE significant cytotoxic effects on isolated hepatocytes were found. ALE showed some toxicity in Wistar rats discerned by increased ALT (Alanine transaminase), ALP (Alkaline phosphatase) activities and MDA (malondialdehyde) quantity, decreased GSH (reduced glutathione) levels without affecting the activity of the antioxidant enzymes (GPx (Gluthatione peroxidase), GR (Glutathione reductase) and GST (Glutathione-S-transferase activity)). The antioxidant and hepatoprotective potential of ALE was also observed in vitro/in vivo against CCl4-induced liver injury, where ALE normalizes all the examined parameters perturbated by CCl4 administration. In addition, ALE preserved the decreased cytochrome P450 level and EMND (Ethylmorphine-N-Demethylase) activity without affecting AH (Aniline 4-Hydroxylase) activity. ALE is rich in anthraquinones, naphthalenes and caffeic acid. The pro-oxidant effects of ALE could be due to naphthalene and anthraquinone bioactivation pathways involving toxic metabolites.

Antidiabetic and antioxidant effects of saponarin from Gypsophila trichotoma on streptozotocin-induced diabetic normotensive and hypertensive rats.

BACKGROUND: Diabetes and hypertension are diseases that often coexist, which increases the risk of chronic organ damages and cardiovascular complications. PURPOSE: To evaluate the effects of saponarin, isolated from Gypsophila trichotoma Wend, on blood pressure, glycemia, body weight, and liver biochemical parameters related to oxidative stress in diabetic normotensive Wistar Kyoto rats (NTR) and spontaneously hypertensive rats (SHR). METHODS: Diabetes was induced by administration of streptozotocin (40 mg/kg, i.p.). The following biochemical parameters: reduced glutathione (GSH), malondialdehyde (MDA), total cytochrome P450, aniline hydroxylase (AH) activity, as well as the activities of antioxidant enzymes such as glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) were measured in the livers of euthanized rats. RESULTS: Saponarin exerted slight antihypertensive activity in non-diabetic SHR, judged by 19% (p<0.05) decrease of the initial blood pressure. However, such effect was not observed in streptozotocin-induced diabetic SHR (SHR-D). Streptozotocin-induced diabetes was evidenced by 78% (p<0.05) and by 171% (p<0.05) increase in blood glucose level in NTR and SHR, respectively. In non-diabetic SHR the initial MDA quantity was by 36% (p<0.05) higher and the initial GSH levels were by 28% (p<0.05) lower in comparison to non-diabetic NTR. Significant decrease in the activities of GPx, GR, and GST was measured in the livers of all diabetic rats. Treatment with saponarin ameliorated the above mentioned liver parameters in both diabetic strains, however its effects were less pronounced in the diabetic SHR group. CONCLUSION: Taken together our data indicate that diabetes and hypertension in combination are more difficult to be modulated by saponarin.

Selective Nitric Oxide Synthase Inhibitor 7-Nitroindazole Protects against Cocaine-Induced Oxidative Stress in Rat Brain.

One of the mechanisms involved in the development of addiction, as well as in brain toxicity, is the oxidative stress. The aim of the current study was to investigate the effects of 7-nitroindazole (7-NI), a selective inhibitor of neuronal nitric oxide synthase (nNOS), on cocaine withdrawal and neurotoxicity in male Wistar rats. The animals were divided into four groups: control; group treated with cocaine (15 mg/kg(-1), i.p., 7 days); group treated with 7-NI (25 mg/kg(-1), i.p., 7 days); and a combination group (7-NI + cocaine). Cocaine repeated treatment resulted in development of physical dependence, judged by withdrawal symptoms (decreased locomotion, increased salivation and breathing rate), accompanied by an increased nNOS activity and oxidative stress. The latter was discerned by an increased formation of malondialdehyde (MDA), depletion of reduced glutathione (GSH) levels, and impairment of the enzymatic antioxidant defense system measured in whole brain. In synaptosomes, isolated from cocaine-treated rats, mitochondrial activity and GSH levels were also decreased. 7-NI administered along with cocaine not only attenuated the withdrawal, due to its nNOS inhibition, but also reversed both the GSH levels and antioxidant enzyme activities near control levels.

Experimental liver protection of n-butanolic extract of Astragalus monspessulanus L. on carbon tetrachloride model of toxicity in rat.

OBJECTIVE: To investigate the hepatoprotective potential of n-butanolic extract of Astragalus monspessulanus L. (EAM) against in-vitro/in-vivo carbon tetrachloride (CCl4)-induced liver damage in rats. Silymarin was used as a positive control. METHODS AND RESULTS: The in-vitro experiments were carried out in primary isolated rat hepatocytes first incubated with CCl4 (86 µmol/l). Hepatic injury was discerned by a decrease in cell viability and cell glutathione (GSH) levels, an increase in lactate dehydrogenase leakage into the medium, and an elevation in malondialdehyde (MDA) quantity. Cell pre-incubation with EAM (1 µg/ml and 10 µg/ml) significantly ameliorated the CCl4-induced liver damage. In-vivo rats were challenged orally with CCl4 (10% solution in olive oil) alone and after 7 days pre-treatment with EAM (100 mg/kg body weight per day, oral gavage). CCl4 damage was judged by an increased production of MDA, depletion of cell GSH, and a decrease in cell antioxidant defense system. EAM pre-treatment normalizes the activities of the antioxidant enzymes and the levels of GSH and MDA. These data are supported by the histopathological examination. CONCLUSION: These results indicate that EAM has a similar significant protective effect, in vitro and in vivo, against CCl4 induced hepatotoxicity in rat as silymarin.This may be due to its antioxidant and membrane stabilizing properties.

Modes-of-Action Related to Repeated Dose Toxicity: Tissue-Specific Biological Roles of PPAR γ Ligand-Dependent Dysregulation in Nonalcoholic Fatty Liver Disease.

Comprehensive understanding of the precise mode of action/adverse outcome pathway (MoA/AOP) of chemicals becomes a key step towards superseding the current repeated dose toxicity testing methodology with new generation predictive toxicology tools. The description and characterization of the toxicological MoA leading to non-alcoholic fatty liver disease (NAFLD) are of specific interest, due to its increasing incidence in the modern society. Growing evidence stresses on the PPAR γ ligand-dependent dysregulation as a key molecular initiating event (MIE) for this adverse effect. The aim of this work was to analyze and systematize the numerous scientific data about the steatogenic role of PPAR γ . Over 300 papers were ranked according to preliminary defined criteria and used as reliable and significant sources of data about the PPAR γ -dependent prosteatotic MoA. A detailed analysis was performed regarding proteins which PPAR γ -mediated expression changes had been confirmed to be prosteatotic by most experimental evidence. Two probable toxicological MoAs from PPAR γ ligand binding to NAFLD were described according to the Organisation for Economic Cooperation and Development (OECD) concepts: (i) PPAR γ activation in hepatocytes and (ii) PPAR γ inhibition in adipocytes. The possible events at different levels of biological organization starting from the MIE to the organ response and the connections between them were described in details.

Some in vitro/in vivo chemically-induced experimental models of liver oxidative stress in rats.

Oxidative stress is critically involved in a variety of diseases. Reactive oxygen species (ROS) are highly toxic molecules that are generated during the body's metabolic reactions and can react with and damage some cellular molecules such as lipids, proteins, or DNA. Liver is an important target of the oxidative stress because of its exposure to various prooxidant toxic compounds as well as of its metabolic function and ability to transform some xenobiotics to reactive toxic metabolites (as ROS). To investigate the processes of liver injuries and especially liver oxidative damages there are many experimental models, some of which we discuss further.

Protective effects of the apigenin-O/C-diglucoside saponarin from Gypsophila trichotoma on carbone tetrachloride-induced hepatotoxicity in vitro/in vivo in rats.

This study investigated the hepatoprotective activity of saponarin, isolated from Gypsophila trichotoma Wend., using in vitro/in vivo hepatotoxicity model based on carbone tetrachloride (CCl4)-induced liver damage in male Wistar rats. The effect of saponarin was compared with those of silymarin. In vitro experiments were carried out in primary isolated rat hepatocytes. Cell incubation with CCl4 (86 µmol l⁻¹) led to a significant decrease in cell viability, increased LDH leakage, decreased levels of cellular GSH and elevation in MDA quantity. Cell pre-incubation with saponarin (60-0.006 µg/ml) significantly ameliorated CCl4-induced hepatic damage in a concentration-dependent manner. These results were supported by the following in vivo study. Along with decreased MDA quantity and increased level of cell protector GSH, seven day pre-treatment of rats with saponarin (80 mg/kg bw; p.o.) also prevented CCl4 (10%, p.o.)-caused oxidative damage by increasing antioxidant enzyme activities (CAT, SOD, GST, GPx, GR). Biotransformation phase I enzymes were also assessed. Administered alone, saponarin decreased EMND and AH activities but not at the same extent as CCl4 did. However, pre-treatment with saponarin significantly increased enzyme activities in comparison to CCl4 only group. The observed biochemical changes were consistent with histopathological observations where the hepatoprotective effect of saponarin was comparative to the effects of the known hepatoprotecor silymarin. Our results suggest that saponarin, isolated from Gypsophila trichotoma Wend., showed in vitro and in vivo hepatoprotective and antioxidant activity against CCl4-induced liver damage.

Hepatoprotective and antioxidant effects of saponarin, isolated from Gypsophila trichotoma Wend. on paracetamol-induced liver damage in rats.

The hepatoprotective potential of saponarin, isolated from Gypsophila trichotoma, was evaluated in vitro/in vivo using a hepatotoxicity model of paracetamol-induced liver injury. In freshly isolated rat hepatocytes, paracetamol (100 µ mol) led to a significant decrease in cell viability, increased LDH leakage, decreased levels of cellular GSH, and elevated MDA quantity. Saponarin (60-0.006 µ g/mL) preincubation, however, significantly ameliorated paracetamol-induced hepatotoxicity in a concentration-dependent manner. The beneficial effect of saponarin was also observed in vivo. Rats were challenged with paracetamol alone (600 mg/kg, i.p.) and after 7-day pretreatment with saponarin (80 mg/kg, oral gavage). Paracetamol toxicity was evidenced by increase in MDA quantity and decrease in cell GSH levels and antioxidant defence system. No changes in phase I enzyme activities of AH and EMND and cytochrome P 450 quantity were detected. Saponarin pretreatment resulted in significant increase in cell antioxidant defence system and GSH levels and decrease in lipid peroxidation. The biochemical changes are in good correlation with the histopathological data. Protective activity of saponarin was similar to the activity of positive control silymarin. On the basis of these results, it can be concluded that saponarin exerts antioxidant and hepatoprotective activity against paracetamol liver injury in vitro/in vivo.

Protective effects of a purified saponin mixture from Astragalus corniculatus Bieb., in vivo hepatotoxicity models.

In this study, the in vivo effects of a purified saponin mixture (PSM), obtained from Astragalus corniculatus Bieb., were investigated using two in vivo hepatotoxicity models based on liver damage caused by paracetamol (PC) and carbon tetrachloride (CCl4 ). The effects of PSM were compared with silymarin. Male Wistar rats were challenged orally with 20% CCl4 or PC (2 g/kg) four days after being pre-treated with PSM (100 mg/kg) or silymarin (200 mg/kg). A significant decrease of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase (LDH) activities and glutathione (GSH) levels and an increase of malondialdehyde (MDA) quantity was observed after CCl4 and PC administration alone. PSM pre-treatment decreased serum transaminases and LDH activities and MDA levels and increased the levels of cell protector GSH. Biotransformation phase I enzymes were also assessed in both models. In the CCl4 hepatotoxicity model, pre-treatment with PSM or silymarin resulted in significantly increased activities of ethylmorphine-N-demethylase and aniline 4-hydroxylase activity and cytochrome P450, compared to the CCl4 only group. Neither silymarin nor PSM influenced PC biotransformation. Our results suggest that PSM, obtained from A. corniculatus, Bieb. showed in vivo hepatoprotective and antioxidant activities against CCl4 and PC-induced liver damage comparable to that of silymarin.