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ABSTRACT 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 [...]

Triterpenoids are well known metabolic syndrome (MetS) modulators. One of the suggested molecular mechanisms of action involves peroxisome proliferator-activated receptor gamma (PPARγ) activation. In this study we aimed to: (i) develop a virtual screening (VS) protocol for PPARγ weak partial agonists, (ii) predict potential metabolic transformations of naturally-derived triterpenoids, and (iii) perform VS of the triterpenoids and their metabolites. The NIH PubMed system was searched for publications about naturallyderived oleanane triterpenoids which are agonists or up-regulators of PPARγ. Structure- and ligand-based methods were combined in the development of the VS protocol. Metabolites were predicted using Meteor Nexus expert system (Lhasa Limited). Two in-house virtual libraries of PPARγ weak partial agonists and naturally-derived triterpenoids with their predicted metabolites were compiled. The pharmacophore-based docking protocol was applied for VS of the collected triterpenoids. Most of the docking poses reproduced the binding mode of caulophyllogenin (a weak partial agonist) in a complex with PPARγ (PDB ID 5F9B). Our results contribute to the mechanistic explanation of the effects of triterpenoids suggesting possible weak partial agonistic activity toward PPARγ. This research can direct further studies on triterpenoids’ role in MetS modulation. The developed protocol can be applied for VS of any PPARγ weak partial agonists. [ABSTRACT FROM AUTHOR]

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. Image 1 • Phase I metabolites of the main sapogenin in purified saponin's mixture (PSM) from Astragalus glycyphylloides were predicted. • PPARγ weak partial agonism was predicted for 24 metabolites of the main PSM sapogenin (oleanolic acid). • PSM safety was confirmed by in silico predictions of toxicity and in vivo acute oral toxicity assessment. • Type 2 diabetes was induced in spontaneously hypertensive rats (SHRs) by treatment with streptozotocin-nicotineamide. • Antihyperglycaemic, hypolipidaemic, antioxidant and hepatoprotective effects of PSM were observed in diabetic SHRs. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 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 μg/mL) preincubation, however, significantly ameliorated paracetamol-induced hepatotoxicity in a concentrationdependent 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. [ABSTRACT FROM AUTHOR]

We extracted Fusarium solani antigens to evaluate specific anti-F, solani IgE in fifty-one induce oxidative stress. In this study we investigated the effects of myosmine on enzymatic and nonenzymatic antioxidative defence in rat liver. Wistar rats received a single i.p. injection of 19 mg kg-1 of myosmine and an oral dose of 190 mg kg-1 by gavage. Nicotine was used as a positive control. Through either route of administration, myosmine altered the hepatic function by decreasing the levels of reduced glutathione, superoxide dismutase, and glutathione peroxidase activities on one hand and by increasing malondialdehyde, catalase, and glutathione reductase activity on the other. Compared to control, both routes caused significant lipid peroxidation in the liver and altered hepatic enzymatic and non-enzymatic antioxidative defences. The pro-oxidant effects of myosmine were comparable with those of nicotine. [ABSTRACT FROM AUTHOR]

The antioxidant effect of saponarin, which is the main flavone isolated from Gypsophila trichotoma Wend., and its protection against cocaine hepatotoxicity were investigated in male Wistar rats. The animals were treated with cocaine (40 mg/kg i.p.) alone and also after 3 consecutive days of pretreatment with saponarin (80 mg/kg p.o.). After 18 hours the rats were sacrificed by decapitation. The production of thiobarbituric acid reactive substances, reduced glutathione (GSH) and the activity of the following antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase were assessed in liver homogenate. Administered alone, cocaine induced significant hepatotoxicity manifested with GSH depletion and reduced antioxidant defences. Saponarin pretreatment, however, decreased cocaine toxicity both by increasing GSH levels and antioxidant enzyme activities. The results of this study proved the antioxidant activity of saponarin and its protective effect against cocaine-induced oxidative stress and hepatotoxicity. [ABSTRACT FROM AUTHOR]

Amphetamine is an example of a drug of abuse that has extensive hepatic biotransformation. In rats it undergoes mainly p-hydroxylation of the aromatic ring, process favorably mediated by CYP 2D. In our previous in virto studies, using inducers and inhibitors of CYP 3A, we suggested an involvement of this isoform in amphetamine's metabolism and toxicity. This poses possible in vivo metabolic interactions of the compound with other substrates of this enzyme, among which are the Ca-channel blockers (nifedipine). On the basis of these data, the aim of the following study was to trace a possible hepatic interaction between amphetamine and nifedipine (CYP 3A substrate and inhibitor), after multiple administration (5 days). For the experiment, male Wistar rats were used. The animals were divided into 4 groups: control; treated with amphetamine; treated with nifedipine and combined group. Changes in cytochrome P 450 quantity, ethylmorphine-Ndemethylase (EMND) activity and aniline hydroxylase (AH) activity, were measured spectrophotometrically. Administered alone, amphetamine led to significant decrease of P 450 quantity by 25% and EMND activity by 40%, without changing AH activity. Nifedipine, compared to the control group, increased P450 quantity, EMND activity and AH activity, by a statistically significant 28%, 35% and 26%, respectively. In the combination group cytochrome P 450 was decreased by 27%, while EMND activity and AH activity were increased by 34% and 21%, versus controls. According to the results of this study we suggest in vivo interactions between amphetamine and nifedipine at the metabolic level. [ABSTRACT FROM AUTHOR]

L-type calcium channel blockers of the dihydropyridine class (Nifedipine) has been reported to modulate morphine effects, including tolerance and dependence development. At the same time, both Nifedipine and Morphine undergo extensive hepatic biotransformation, mediated by cytochrome P 450 CYP 3A isoform. Thus, these two classes of compound could be substrate competitors for CYP 3A.The aim of the following study was to investigate a possible influence of nifedipine, after multiple (7 days) administartion along with morphine, on some metabolic biochemical parameters and urinary excretion. Male Wistar rats were divided into four groups: control; treated with nifedipine (5 mg/kg i.p., twice daily); treated with morphine (5-30 mg/kg i.p., twice daily, 7 days); combined group. Quantity of cytochrome P 450 and activity of ethylmorphine-Ndemethylase (EMND) were measured spectrophotometrically. Urine samples were collected at the 8th day, 24 hours after the last morphine administration, alone and along with nifedipine. The urinary excretion of morphine was determined, using GC/MS method. Cytochrome P 450 quantity and EMND activity were significantly increased by 13% and 27% and by 56% and 35% respectively. This was accompanied by significant decrease in urinary excretion of morphine, by 57%, when is administered together with nifedipine. At the same time toxic effects, such as suppressed locomotor activity, respiratory depression, cyanosis and increased death, were observed among the animals of the combination group. These results suggest metabolic interaction between morphine and nifedipine that leads to decrease in morphine urinary excretion and increased toxicity in the combination group. [ABSTRACT FROM AUTHOR]

Amphetamine is a widely used drug of abuse, known with its hepatotoxic effects both in humans and rats. There are literature data about amphetamine hepatocellular damage, investigated mainly in normotensive Wistar rats. The aim of the following study was to ivestigate d-amphetamine hepatotoxicity in spontaneously hypertensive rats (SHR) in terms of serum ALAT activity, reduced glutathione (GSH) level, malone dialdehyde (MDA) quantity. The total cytochrome P450 quantity and activities of some hepatic microsomal enzymes - ethylmorphine-N-demethylase (EMND), aniline-hydroxilase (AH), were assessed, as well. For the experiments, male SHR (n=12), strain Okamoto Aoki, were used. The animals were divided into two groups: control group and group, treated with d-amphetamine (5 mg/ kg i.p. 5 days). The results of our study showed that d-amphetamine treatment significantly increased serum ALAT activity, which correlated with depletion of GSH level by 28% and an increase lipid peroxidation. The EMND activity and the cytochrome P450 quantity were significantly increased by 35% and by 34%, respectively, compared to the control levels, without any change in AH activity. It is known that in Wistar rats, amphetamine may inhibit cytochrome P 450. Our results, concerning P450 quantity and EMND activity in SHR, are opposite to those in Wistar rats. We supposed, by an observed increased activity of EMND, that this izoenzyme may play a role in biotransformation and toxicity of D-amphetamine in this pathological strain On the base of this study we might suggest that biochemical differences in hypertensive rats, after multiple D-amphetamine administration, are probably due to different pathophysiologyc characteristics of SHRs. [ABSTRACT FROM AUTHOR]

The aim of this study was to trace D-amphetamine toxicity in isolated rat hepatocytes and to elucidate a possible involvement of CYP3A in the mechanisms of its toxicity. To this end, male Wistar rats were treated with nifedipine (5 mg kg-1 i.p., 5 days), a substrate and inducer of CYP3A. Hepatocytes isolated from nifedipine-treated and control rats were incubated with D-amphetamine at a concentration of 100 µmol L-1, which was determined to be an average toxic concentration (TC50) for the compound. To evaluate the possible toxic effects of D-amphetamine on freshly isolated rat hepatocytes, we assessed the following parameters: cell viability, lactate dehydrogenase (LDH) activity, and glutathione (GSH). The results showed that nifedipine potentiated amphetamine cytotoxicity in vitro, as follows: cell viability dropped by 65 % (p<0.001), GSH by 80 % (p<0.001), and LDH activity increased by 190 % (p<0.001). To clarify the role of nifedipine in amphetamine cytotoxicity, we used amiodarone, a substrate and an inhibitor of CYP3A. Pre-incubation of nifedipine-treated hepatocytes with amiodarone (14 µmol L-1) significantly lowered amphetamine cytotoxicity. Our results confirmed the toxicity of D-amphetamine in isolated rat hepatocytes and the involvement of CYP3A in its metabolism and hepatotoxicity. [ABSTRACT FROM AUTHOR]

A purified saponin mixture (PSM) isolated from Astragalus corniculatus Bieb. (Fabaceae) was investigated for its protective effect in two models of toxicity, carbon tetrachloride (CCl4) and tert-butyl hydroperoxide (t-BuOOH), using isolated rat hepatocytes. CCl4 undergoes dehalogenation in the liver endoplasmic reticulum. This process leads to trichlormethyl radical (CCl3) formation, initiation of lipid peroxidation, and measurable toxic effects on the hepatocytes. Oxidative damage is widely recognized as being involved in the development of many pathological conditions. In our experiment, t-BuOOH was used as a model of oxidative stress. The hepatocytes were incubated with the PSM alone (0.01-100 μ M) and along with CCl4 (86 μ M) and t-BuOOH (75 μ M). As a sign of cytotoxicity, cell viability was used. CCl4 and t-BuOOH significantly decreased hepatocyte viability. Our data indicate that PSM showed lower toxic effects compared to CCl4 and t-BuOOH and in combination exerted statistically significant protection of cell viability against the toxic agents. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate possible changes caused by multiple cocaine administration, alone and in combination with 1,4-dihydropiridine calcium channel blocker nifedipine, on cytochrome P450 levels both in the brain and liver. The experiment was done on male Wistar rats divided in four groups: control, treated with nifedipine (5 mg kg-1 i.p. for five days), treated with cocaine (15 mg kg-1 i.p. for five days), and treated with nifedipine and 30 minutes later with cocaine (also for five days). Total cytochrome P450 was measured spectrometrically in liver and brain microsomes. Multiple administration of cocaine alone and in combination with nifedipine did not change the brain P450 significantly. In the liver, nifedipine significantly increased P450 by 28 % vs. control. In contrast, cocaine significantly decreased P450 by 17 % vs. control. In animals treated with nifedipine and cocaine, cytochrome P450 increased 11 % (p<0.01) vs. control, decreased 12.5 % (p<0.001) vs. nifedipine group and increased 34 % (p<0.0001) vs. cocaine group. These results suggest that the cocaine and nifedipine interact at the metabolic level. [ABSTRACT FROM AUTHOR]

Five benzophenones and a xanthone, isolated from Hypericum annulatum Moris, were investigated for their protective effect against carbon tetrachloride toxicity in isolated rat hepatocytes. The benzophenones and the xanthone gentisein were administered alone (100 μM) and in combination with CCl4 (86 μM). CCl4 undergoes dehalogenation in the liver endoplasmic reticulum. This process leads to trichlormethyl radical (•CCl3) formation, initiation of lipid peroxidation, and measurable toxic effects on the hepatocytes. The levels of thiobarbituric acid reactive substances (TBARS) were assayed as an index of lipid peroxidation (LPO). Lactate dehydrogenase (LDH) leakage, cell viability and reduced glutathione (GSH) depletion were used as signs of cytotoxicity. CCl4 significantly decreased hepatocyte viability, GSH level and increased TBARS level and LDH leakage as compared to the control. Our data indicate that 2,3′,5′,6–tetrahydroxy–4-methoxybenzophenone, 2–O-α-L–arabinofuranosyl-3′,5′,6–trihydroxy–4-methoxybenzophenone and 2-O-α-L-3′-acetylarabinofuranosyl-3′,5′,6-trihydroxy-4-methoxybenzophenone showed weaker toxic effects compared to CCl4 and in combination showed statistically significant protection against the toxic agent. [ABSTRACT FROM AUTHOR]

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 LD 50 = 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 (IC 50 27.24 μg/mL) than acarbose (IC 50 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. • 3,5-diCQA from Geigeria alata roots is slightly toxic (LD 50 = 2154 mg/kg). • 3,5-diCQA is more potent α - glucosidase inhibitor than acarbose. • 3,5-diCQA reduced blood glucose and blood pressure in diabetic hypertensive rats. • 3,5-diCQA ameliorated oxidative stress biomarkers and serum biochemistry. • 3,5-diCQA prevents histopathological changes related to diabetes and hypertension. [ABSTRACT FROM AUTHOR]

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. Image 1 • New toxicity database enriched with antimicrobial chemicals for TTC approach. • Thresholds are derived from the AM TTC Dataset for Cramer Classes I, II, and III. • Antimicrobial structure categories are defined and stratified for potency classes. [ABSTRACT FROM AUTHOR]

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.

Tobacco smoking is a risk factor for variety of cardio-vascular diseases, such as hypertension, myocardial infarction, stroke and many others. It is of great importance for hypertensive patients to stop smoking. One of the medicines widely used for smoking cessation in Bulgaria is the original Bulgarian product Tabex®, which is developed on the basis of natural plant alkaloid cytisine. The aim of the following study was to ivestigate the effects of cytisine on some brain and hepatic biochemical parameters in spontaneously hypertensive rats (SHR), an widely used rodent model for human essential hypertension, and to compare the obtained results with their age-matched normotensive controls Wistar Kyoto (WKY). Multiple cytisine administration did not affect the activity of ethylmorphine-N-demethylase (EMND) and anylinehydroxylase (AH), as well as the quantity of cytochrome P 450, nor in WKY neither in SHR In the liver cytisine increased the MDA quantity both in SHR and in WKY, by 25% (p<0.05) and by 29% (p<0.05) respectively, while the GSH level was not significantly changed by the compound in both strains. In contrast, on the brain level, cytisine administration to SHR caused more prominent toxicity, resulted in GSH depletion and increased MDA quantity, while in WKY strain did not exert any toxicity. Cytisine did not significantly affect ALAT and ASAT activity in both strains. In conclusion, the results of our study suggest higher brain toxicity of cytisine in spontaneously hypertensive rats, that might be due to their pathophysiological characteristics.