Saša Vukmirović

The Protective Effects of Silymarin against Doxorubicin-Induced Cardiotoxicity and Hepatotoxicity in Rats

Silymarin is a complex of five major compounds, and silibinin is the most biologically active component of the complex. The aim of this study was to investigate, evaluate and confirm the potential cardioprotective and hepatoprotective effects of administration of silymarin, rich in silibinin, at a dose of 60 mg/kg orally for a time-span of 12 days on doxorubicin induced toxicity in male Wistar rats. The in vivo model was used to explore whether silymarin could prevent damage of liver and heart tissue induced by doxorubicin administered every other day at dose of 1.66 mg/kg intraperitoneally for twelve days. In the study the change of body weight, ECG changes, biochemical parameters of oxidative stress, serum activity of alanine and aspartate transaminase, lactate dehydrogenase, creatine kinase and histological preparations of heart and liver samples of treated animals were examined. According to physiological, pharmacological, microscopic and biochemical results, we confirmed that at the examined dose, silymarin exhibits a protective influence on the heart and liver tissue against toxicity induced by doxorubicin.

Anti-oxidative activity of an aqueous suspension of commercial preparation of the mushroom Coprinus comatus.

In this study the effects of an aqueous suspension of a commercial preparation of the mushroom Coprinus comatus on oxidative stress induced in rats by alloxane and carbon tetrachloride was examined. The effects were estimated from changes in the biochemical parameters (xanthine oxidase, glutathione peroxidase and catalase activity, reduced glutathione content, and extent of lipid peroxidation) of liver homogenate as well as histological changes in the liver of the rats treated with alloxane and carbon tetrachloride. Two screening doses of alloxane sufficient to induce diabetes in rats did not have any significant effect on the examined biochemical parameters of liver homogenate or on the cytoarchitectonics of liver cross-sections. Treatment with carbon tetrachloride resulted in a significant increase in the intensity of lipid peroxidation and peroxydasis activity, as well as with decrease in catalase activity. Certain changes in liver cross sections were detected, such is lymphocyte infiltration of dilated sinusoid capillaries. Administration of Coprinus comatus suspension thus showed antioxidative potential, evidenced by an increase of antioxidative status of liver homogenate and prevention of histological changes in liver cross sections.

Effect of rat pretreatment with aqueous solutions of stevioside and bile acids on the action of certain cardioactive drugs

SummaryThe interaction of aqueous solutions of stevioside and bile acids with cardioactive drugs was studied in rats by registering changes in their electrocardiograms (ECG). Wistar rats of both sexes received daily doses of 20 mg/kg (i.p.) of an aqueous solution of stevioside or physiological solution (controls), then were narcotized with urethane and connected to the ECG apparatus for the first recording. The jugular vein was prepared and connected to an infusion pump to administer one of the drugs: adrenaline (0.1 mg/ml), verapamil (2.5 mg/ml) or metoprolol (1 mg/ml) to rats in both groups, while recording their ECGs. In the second part of the study, the animals were treated in the same way but instead of the stevioside solution received a single dose of 4 mg/kg of monoketocholic acid methyl ester (ME) or sodium salt of the same bile acid (MKHNa), 30 minutes before cardioactive drug infusion. The infusion rate of cardioactive drugs was 0.2 ml/min, except for verapamil (0.1 ml/min). The events observed on ECG recordings were the first myocardial reaction to drug infusion, the second longer-lasting reaction (observed as more extended extrasystoles, decrease in intensity of the QRS complex, or changes in heart rate frequency), and toxicity effect. In the control animals, adrenaline induced a decrease in heart rate frequency at a dose of 0.094 mg/kg, while with stevioside-pretreated rats this effect appeared significantly earlier (at a dose of 0.018 mg/kg). No toxic effect of adrenaline was observed, either in control or stevioside-pretreated group. Bile acids caused no changes in myocardial reaction to adrenaline. Only in the group of animals that received MKHNa, a significant decrease in the QRS complex was observed. Finally, the infusion of stevioside to intact animals at doses of 45 and 55 mg/kg caused no significant changes in the ECG patterns. The myocardial reaction to metoprolol remained unchanged in rats of all groups when compared with controls except for a mild decrease in heart rate frequency. Stevioside inducedproduced a significant increase in myocardial sensitivity to verapamil, but no toxic effect was observed in any of the cases. A similar conclusion also holds for the interaction with MKHNa, whereas ME caused an increase in the toxicity of verapamil.

Consumption of serum lipid-reducing drugs in Serbia compared with Scandinavian countries: a population-based study, 2004–2008

The aim of this study was to measure the consumption of serum lipid reducing drugs in Serbia from 2004 to 2008, to compare this data with that from Scandinavian countries, and to compare the consumption of lipid lowering drugs and the rate of mortality from cardiovascular diseases in these countries.

Pharmacodynamic Action of a Commercial Preparation of the Mushroom Coprinus comatus in Rats

The pharmacodynamic effect of a 7‐day oral treatment with a suspension of Coprinus comatus at doses of 0.835 and 1.670 g/kg in rats was studied. Changes in body weight, bile secretion and hypoglycaemic action were examined together with antipyretic activity and paw oedema tests. Such treatments resulted in a significantly lower increase in the body weight of tested animals (15.73 ± 8.36 g/rat in the untreated group, 8.44 ± 8.23 g/rat (p < 0.05) and 3.18 ± 7.93 g/rat (p < 0.05), for C. comatus 0.835 and 1.67 g/kg, respectively). Hypoglycaemic action was evident only in the glucose load test (6.79 ± 0.61 to 9.70 ± 1.16 (p < 0.05) in the untreated group and 6.47 ± 0.35 to 7.27 ± 0.76 for C. comatus 1.67 g/kg). Histological examination of pancreas cross‐sections suggested certain protective functions of the mushroom suspension in alloxan poisoning. In the antipyretic test, a significantly lower increase in body temperature was observed in the mushroom‐pretreated rats. In the paw oedema test, no decrease in oedema induced by formalin injection was observed following treatment with C. comatus. Copyright

Retention data of bile acids and their oxo derivatives in characterization of pharmacokinetic properties and in silico ADME modeling.

PURPOSE Information on ADME properties of examined bile acids and their oxo derivatives are scarce, although the interest for bile acids and their use in nanochemistry and macromolecular chemistry is increasing. The purpose of this research was to evaluate the lipophilicity, a crucial physicochemical parameter for describing ADME properties of selected bile acids and their oxo derivatives, and to compare two approaches: experimentally determined hydrophobicity parameters and calculated logP values. METHODS Commercially available bile acids - deoxycholic, chenodeoxycholic, hyodeoxycholic and ursodeoxycholic acid were used to synthesize oxo derivatives. Lipophilicity was evaluated in two solvent systems: toluene/ethanol and toluene/butanol. Retention parameters were acquired by normal-phase TLC. The correlations between calculated logP values obtained using five different software and experimentally determined hydrophobicity parameters (RM(0)(tol/eth), RM(0)(tol/but), b(tol/eth) and b(tol/but)) were examined. RESULTS Correlation analysis confirmed significant dependence between experimental RM(0) values and software calculated parameters. Results suggest satisfactory intestinal absorption after oral administration for all of the examined compounds as well as low volumes of distribution, and high affinity for binding with plasma proteins. Penetration through blood-brain barrier and skin is not satisfactory. All of the examined compounds show high affinity for binding with G-protein coupled receptors and consequently inhibition of ionic channels. Results also suggest possible binding with nuclear receptors. CONCLUSIONS Established lipophilicity testing model of studied compounds showed excellent predictive ability and might represent significant tool in development of relations between chromatographic behavior and ADME properties. Compounds 3α-hydroxy-7,12-dioxo-5β-cholanoic and 12α-hydroxy-3,7-dioxo-5β-cholanoic acid might be the most suitable candidates for further development studies (satisfactory pharmacokinetic properties and lowest haemolytic potential) followed by 3α-hydroxy-12-oxo-5β-cholanoic acid and 3α-hydroxy-7-oxo-5β-cholanoic acid (slightly higher haemolytic potential, but better ligand properties).

Assessment of the pharmacokinetic profile of novel s-triazine derivatives and their potential use in treatment of Alzheimer's disease

Aims: The current treatment of Alzheimers disease is purely symptomatic. Scientists are looking for new treatment options which could alter the course of the disease and improve the quality of life in patients with Alzheimers disease. In this paper 14 novel s‐triazine molecules have been evaluated for their lipophilicity. In addition docking study was carried out to evaluate acetylcholinesterase activity of these compounds. Main methods: Lipophilicity was evaluated by RP HPTLC using 5 different mobile phases and obtained results were used in calculations of pharmacokinetic parameters ‐ logBB, Ka and Pej. Multiple linear regression analysis was refined, taking account of molecular polarity (total polar surface area, TPSA) and molecular weight (Mw) descriptors. Appropriate QSAR models were developed. Docking studies were carried out using the Vina docking. Key findings: Five out of fourteen compounds evaluated [5‐10] are selected as the most promising compounds with satisfactory pharmacokinetic properties and good docking scores. Significance: Compound 10 possesses the best combination of favourable pharmacokinetic characteristics (brain penetration, intestinal absorption) and capacity for acetylcholinesterase inhibition. Consequently this molecule should be further evaluated for potential therapeutic use in Alzheimers disease.

Structural insights into anticancer activity of D-ring modified estrone derivatives using their lipophilicity in estimation of SAR and molecular docking studies

Many forms of breast carcinoma are hormone-dependent and therefore development of novel aromatase inhibitors is of particular interest. Since brain metastases are frequent in patients with advanced breast carcinoma, one of the goals of modern drug development is the discovery of drugs with specific pharmacokinetic profile. High performance thin layer chromatography (HPTLC) is often used to determine lipophilicity of the molecules based on their retention constant. As a predictive analysis, multiple linear regression method was performed to connect pharmacokinetic-dependent parameters with independent physicochemical properties such are: RM0 , TPSA and Mw of fourteen D-ring modified oestrone derivatives. Additionally, docking studies were performed. Conducted correlation analysis indicates excellent dependence between experimental RM parameter values and calculated values of pharmacokinetic parameters. Results show sufficient intestinal absorption of all the investigated molecules as well as moderate volumes of distribution and strong affinity for binding to plasma proteins. Crossing blood-brain barrier is predicted to be successful for 11 compounds. The created quantitative structure activity relationship model represents an excellent predictive tool and enables determination of pharmacokinetic properties of examined compounds. Docking analysis defined molecules I3 and II3 to be the best candidates; however, compound II3 violates the Lipinski rule. It has been concluded that molecules with hydroxyl group at C-3 more effectively pass through blood-brain barrier while structures with benzyloxy groups have stronger interactions with CYP1A19. Molecules II2 , II4 , II6 , and II7 are regarded as most suitable candidates for further investigation considering their good pharmacokinetic and docking characteristics. Copyright

Interaction between different extracts of Hypericum perforatum L. from Serbia and pentobarbital, diazepam and paracetamol.

Herb-drug interactions are an important safety concern and this study was conducted regarding the interaction between the natural top-selling antidepressant remedy Hypericum perforatum (Hypericaceae) and conventional drugs. This study examined the influence of acute pretreatment with different extracts of Hypericum perforatum from Serbia on pentobarbital-induced sleeping time, impairment of motor coordination caused by diazepam and paracetamol pharmacokinetics in mice. Ethanolic extract, aqueous extract, infusion, tablet and capsule of Hypericum perforatum were used in this experiment. The profile of Hypericum perforatum extracts as well as paracetamol plasma concentration was determined using RP-HPLC analysis. By quantitative HPLC analysis of active principles, it has been proven that Hypericum perforatum ethanolic extract has the largest content of naphtodianthrones: hypericin (57.77 µg/mL) and pseudohypericin (155.38 µg/mL). Pretreatment with ethanolic extract of Hypericum perforatum potentiated the hypnotic effect of pentobarbital and impairment of motor coordination caused by diazepam to the greatest extent and also increased paracetamol plasma concentration in comparison to the control group. These results were in correlation with naphtodianthrone concentrations. The obtained results have shown a considerable influence of Hypericum perforatum on pentobarbital and diazepam pharmacodynamics and paracetamol pharmacokinetics.

Insight into anti-diabetic effect of low dose of stevioside

Diabetes mellitus is a chronic disease characterized by abnormal carbohydrate, lipid and protein metabolism due to a lack of insulin or reduced target cell sensitivity to insulin. Stevia rebaudiana is an important source of biochemically active substances with proven anti-diabetic effect. The aim of this study was to determine anti-diabetic effects of the low dose of stevioside in NMRI Haan mice. Aqueous stevioside solution (20mg/kg body weight) was administered by oral route of administration. Anti-diabetic effect of stevioside was estimated by oral glucose tolerance test, adrenaline test after a 10day stevioside treatment, and alloxan induced hyperglycaemia in mice (two experimental groups, 10day stevioside treatment before and after alloxan administration). Aqueous stevioside solution prevented significant increase in glycaemia in oral glucose tolerance test (9.22±1.13 to 9.85±1.32mmol/l, P<0.05), and not in adrenaline test. Significant difference in glycaemia was detected in mice pre-treated with saline and stevioside in alloxan induced hyperglycaemia (saline 23.32±2.14, stevioside 14.70±4.95mmol/l, P<0.05). In mice pre-treated with stevioside, smallest β cells loss was found compared to other alloxan treated groups. Preserved normal cytoarchitectonic arrangement in islets was detected. Based on the given results we presume there exist a potential therapeutic use of low dose stevioside in diabetes.