Rat Liver Homogenates Research Articles

Effects of Rhus coriaria L. hydroalcoholic extract on the lipid and antioxidant profile in high fat diet-induced hepatic steatosis in rats

Oxidative stress is related to increased fat deposition in the liver, known as hepatic steatosis. The present study is an evaluation of the anti-oxidative and antihyperlipidemic effects of the hydroalcoholic extract of Rhus coriaria L. (HARE) in rats on a high-fat diet (HFD). Twenty male Wistar rats were divided into four groups: control, HFD, HFD + HARE 50 mg/kg/day, and HFD + HARE 250 mg/kg/day for 12 weeks. Animals were weighed weekly and treated with the HARE extract for 12 weeks by gavage. Subsequently, the histopathological changes, oxidative markers, and lipid profile were evaluated. Statistical analysis was performed using the one-way analysis of variance (ANOVA) for multiple comparisons. First, the active ingredients of the extract were determined by HPLC. Then, the levels in the serum lipid profile (TG, cholesterol, HDL, and LDL) in rats fed with the HFD + HARE were analyzed where a significant reduction was observed. The HFD proved to increase the activity of the liver enzymes, the serum lipid levels, and the malondialdehyde (MDA) level. The ferric-reducing antioxidant activity power (FRAP), catalase (CAT), and superoxide dismutase (SOD) catalytic activity were reduced in the liver homogenate of HFD rats compared to the controls. Additionally, the aforementioned liver enzymes activities were reduced in response to HARE. Evaluation of oxidative stress determined a reduction in the MDA level while a raised FRAP was confirmed. In accordance with the present results, histopathological observations have also demonstrated that HARE ameliorated grade-1 hepatic steatosis induced by HFD. Taken together, the findings of this study introduce HARE as a future potential therapeutic agent in treating hepatic steatosis and reducing oxidative damages of an HFD in the liver.

Inhibition of HMG CoA Reductase and Lipid Peroxidation in The Rats Liver by Selected Zingiberaceae

Cardiovascular disease is the leading cause of death worldwide. One of the major risk factors for cardiovascular disease is hyperlipidemia. This study aimed to determine the potential of Zingiberaceae (10 species) as inhibitor of HMG-CoA reductase enzyme activity and lipid peroxidation. This study was conducted by 2 methods including assay of HMG CoA reductase inhibition and lipid peroxidation test. The study was performed by in vitro method, using 20% rat liver homogenate. The inhibition of HMG CoA reductase enzyme was done by reacting liver homogenate, HMG CoA substrate, which added the Zingiberaceae extract compared with simvastatin as standard drug. The absorbance of the mixture was measured by a Microlab 300 spectrophotometer at a 340 nm wavelength. Lipid peroxidation assay was induced by the FeSO4.7H2O solution. The absorbance value measured using a spectrophotometer at a 532 nm wavelength. Lipid peroxidation inhibition was characterized by absorbance of the test extract, compared with the control group. The obtained data was calculated as percent of inhibition and was used to calculate IC50 extract test. The results showed that the 10 ethanolic extracts of Zingiberaceae rhizomes have activity as enzyme inhibitor HMG-CoA reductase with IC50 value range 65.8±4.1 – 203.3±15.2 ppm, and inhibition of lipid peroxidation with IC50 value range 13.5±5.0 – 219.6±4.3 ppm. This study can be concluded that the Zingiberaceae rhizomes have potential role as antihyperlipidemic agents through inhibition of HMG CoA reductase enzyme activity and preventing lipid peroxidation.

Novel diphenylsulfimide antioxidants containing 2,6-di-tert-butylphenol moieties

New diphenylsulfimide derivatives containing substituents with the 2,6-di-tert-butylphenol moiety at the nitrogen atom were synthesized. Their molecular structures were established by X-ray diffraction. Antioxidant activity was experimentally evaluated by spectrophotometry based on hydrogen transfer to the stable radicals, namely, 2,2-diphenyl-1-picrylhydrazyl and the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS·+), and using in vitro lipid peroxidation in rat brain and liver homogenates. The presence of phenol and diphenylsulfimide moieties in one molecule leads to a significant enhancement of antioxidant activity. The new compounds exhibit moderate inhibitory activity against enzymes involved in carbohydrate and lipid metabolism. The evaluation of antiglycation activity showed that the new sulfimides taken at a concentration of 100 μmol L–1 have activity comparable with that of aminoguanidine.

Methanol fraction of Calliandra portoricensis root bark activates caspases via alteration in mitochondrial viability in vivo

Introduction: Dysregulated apoptosis is associated with a number of disease conditions. Traditionally, Calliandra portoricensis is used in the management of prostate enlargement. This study investigates the in vivo effect of potent methanol fraction of C. portoricensis (MFCP) on mitochondrial permeability transition (mPT) pore, an important pharmacological target in treatment of various diseases, and examines the toxicities associated with its oral administration.Methods: Forty-two male Wistar strain rats (70-80 g) were divided into 6 groups of 7 animals each. Each group was orally administered 25, 50, 100, 200, 400 mg/kg MFCP and the control group received distilled water for 21 and 30 days, respectively. mPT, assay for serum enzymes and hematological parameters were assessed spectrophotometrically while activation of caspases 3 and 9 was done by ELISA technique. Histological assessment of vital organs (liver, kidney, prostate) was carried out according to standard procedures.Results: There were no significant effects on mPT pore at all doses administered after 21 days of oral administration. However, after 30 days of administration, MFCP induced mPT pore opening at doses 100 and 200 mg/kg with induction folds of 2.6 and 3.3, respectively while there was no induction of mPT pore opening at lower doses of 25 mg/kg and 50 mg/kg. Furthermore, significant (P < 0.05) increases in serum enzymes (ALT, AST) were observed at all doses administered when compared with control after 30 days of oral administration. Cell counts (Hb, PCV, RBC, WBC) were adversely affected at the highest dose (200 mg/kg) compared with control and other treated groups (25, 50 and 100 mg/kg) after 30 days of administration. Similarly, activation of caspases 9 and 3 were observed in rat liver homogenate at high doses of the fraction while histological evaluation showed degeneration and distortion of organs at the highest dose.Conclusion: MFCP contains phytochemicals that elicit the opening of the pore and induction of mitochondrial-mediated apoptosis. This would be relevant in treatment of degenerative diseases that results from down-regulation of apoptosis. However, caution should be exercised in using high doses of the plant.

Synthesis and DNase I inhibitory properties of some 4-thiazolidinone derivatives.

Twelve new thiazolidinones were synthesized and, together with 41 previously synthesized thiazolidinones,evaluated for inhibitory activity against deoxyribonuclease I (DNase I) in vitro. Ten compounds inhibited commercial bovine pancreatic DNase I with an IC50 below 200 μM and showed to be more potent DNase I inhibitors than crystal violet (IC50 = 365.90 ± 47.33 μM), used as a positive control. Moreover, three compounds were active against DNase I in rat liver homogenate, having an IC50 below 200 μM. (3-Methyl-1,4-dioxothiazolidin-2-ylidene)-N-(2-phenylethyl)ethanamide (41) exhibited the most potent DNase I inhibition against both commercial and rat liver DNase I with IC50 values of 115.96 ± 11.70 and 151.36 ± 15.85 μM, respectively. Site Finder and molecular docking defined the thiazolidinones interactions with the most important catalytic residues of DNase I, including the H-acceptor interaction with residues His 134 and His 252 and/or H-donor interaction with residues Glu 39 and Asp 168. The three most active compounds against both commercial and rat liver DNase I (31, 38, and 41) exhibited favorable physico-chemical, pharmacokinetic, and toxicological properties. These observations could be utilized to guide the rational design and optimization of novel thiazolidinone inhibitors. Thiazolidinones as novel DNase I inhibitors could have potential therapeutic applications due to the significant involvement of DNase I in the pathophysiology of many disease conditions.

Lipid Lowering and Antioxidant Activities of Methanolic Extract of &lt;i&gt;Ficus hispida&lt;/i&gt; Linn. Fruits in Cholesterol Fed Rats

The present study was designed to evaluate the effect of fruits extracts (Ficus hispida) on serum lipids and antioxidant status in hypercholesterolaemic rats. Hyperlipidemia was induced by feeding high fat diet for 28 days and was evidenced by elevated levels of serum triglycerides (TG), serum LDL cholesterol and decreased serum HDL cholesterol. Oxidative stress was measured by determining the activity of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), and amount of thiobarbituric acid reactive substances (TBARS) in liver homogenate of experimental rats. In hypercholesterolaemic rats, crude methanolic extract (CME) consumption had no effect on HDL-cholesterol, yet it showed a marked hypolipidaemic action, decreasing TG and LDL-cholesterol that had been increased after consuming the high-cholesterol diet. On the other hand, the concentration of TBARS decreased significantly, indicating decreased lipid peroxidation. In addition, the activities of catalase and SOD increased significantly in liver homogenate. The above evidence suggested that CME of the fruits of this plant can be a source of natural antioxidant that can reduce the plasma lipid (cholesterol) level and also decreases the lipid peroxidation.

Electrochemical behavior and anti/prooxidant activity of thioethers with redox-active catechol moiety

A number of asymmetrical thioethers combining sterically hindered catechol moiety and different groups (polar, non-polar, or redox active) at sulfur atom have been synthesized. Redox transformations of sulfides were studied by cyclic voltammetry. The electrooxidation of thioethers at the first stage leads to the formation of o-benzoquinones. The presence of a redox-active thioether linker and additional phenolic fragment favors to an extension of the range of redox properties for such functionalized catechols. The introduction of the thioether fragment into catechol ring affects not only the electrochemical behavior of the compounds, but also the antioxidant activity. The antioxidant activities of the compounds were evaluated using 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH) assay, the oxidative damage of the DNA, the reaction of 2,2′-azobis(2-amidinopropane dihydrochloride) (AAPH)-induced glutathione depletion, and the process of lipid peroxidation of rat liver (Wistar) homogenates in vitro. The compounds have greater antiradical effect than 3,5-di-tert-butylcatechol (CatH2) in DPPH assay. In the course of the AAPH-induced oxidative DNA damage, all tested compounds exhibit inhibitory activity unlike CatH2. Among the compounds under investigation, three catechol thioethers reveal mostly antioxidant properties. Several compounds with polar groups possess dual anti/prooxidant activity. The thiolation of catechol ring can change properties of target thiothers by a variation of different organic fragments at sulfur atom.

Antioxidant activity and mechanism of commercial Rama Forte persimmon fruits (Diospyros kaki).

This study aimed to characterize the antioxidant properties of Rama Forte persimmon, a tannin-rich fruit variety produced in Brazil. Extracts prepared with lyophilized pulps from fruits obtained in local markets were analyzed individually to evaluate the extent of antioxidant protection and investigate the antioxidant mechanism. Iron-mediated hydroxylation of 5,5-dimethyl-1-pirrolidine-N-oxide, determined by electron paramagnetic resonance (EPR), and oxidative degradation of 2-deoxyribose (2-DR) were inhibited by fruit extracts in a dose-dependent manner. There was a considerable individual variability in inhibition of 2-DR degradation by individual fruits. Higher protection of 2-DR degradation (by the extracts) was observed in Fe(III)-citrate/ascorbate in comparison with Fe(III)-EDTA/ascorbate system; however, antioxidant effectiveness of fruit extracts was not diminished by increasing EDTA concentration by 10-fold. Other competition experiments using the 2-DR assay (varying pre-incubation time and 2-DR concentration) indicated that protection comes mainly from free radical scavenging, rather that metal chelation antioxidant activity. Persimmon extracts prevented iron-mediated lipid peroxidation in rat liver homogenates, which correlated significantly with the inhibition of 2-DR oxidation. Finally, sugar content of individual fruits correlated inversely with inhibition of 2-DR degradation, which could indicate that maturation decreases soluble antioxidant concentration or efficiency. In conclusion, lipid peroxidation, 2-DR and EPR experiments indicated that extracts from commercial fruits showed mainly radical-scavenger activity and relevant antioxidant activity.

Secondary carbamate linker can facilitate the sustained release of dopamine from brain-targeted prodrug

To achieve the sustained release of dopamine in the brain for the symptomatic treatment of Parkinson’s disease, dopamine was conjugated to l-tyrosine, an l-type amino acid transporter 1 (LAT1)-targeting vector, using a secondary carbamate linker. The resulting prodrug, dopa-CBT, inhibited the uptake of the LAT1 substrate [14C]-l-leucine in LAT1-expressing MCF-7 cells with an IC50 value of 28 µM, which was 3.5-times lower than that of the gold standard for dopamine replacement therapy, l-dopa (IC50 ca. 100 µM). Despite its high affinity for LAT1, dopa-CBT was transported via LAT1 into MCF-7 cells 850-times more slowly (Vmax < 3 pmol/min/mg) than l-dopa (Vmax 2.6 nmol/min/mg), most likely due to its large size compared to l-dopa. However, dopa-CBT was significantly more stable in 10% rat liver homogenate than l-dopa, releasing dopamine and l-tyrosine, an endogenous dopamine precursor, slowly, which indicates that it may serve as a dual carrier of dopamine across the blood-brain barrier selectively expressing LAT1.

Evaluating prodrug characteristics of a novel anticoagulant fusion protein neorudin, a prodrug targeting release of hirudin variant 2-Lys47 at the thrombosis site, by means of in vitro pharmacokinetics

Recombinant neorudin (EPR-hirudin, EH), a low-bleeding anticoagulant fusion protein, is an inactive prodrug designed to be converted to the active metabolite, hirudin variant 2-Lys47 (HV2), locally at the thrombus site by FXa and/or FXIa, following activation of the coagulation system. Our aim was to evaluate the prodrug characteristics of EH by comparing the biotransformation of EH and HV2 in biological matrices, including rat blood, liver, and kidney homogenates, demonstrating the cleavage of EH to HV2 by FXa and FXIa, and comparing the conversion of EH to HV2 between fresh whole blood and whole-blood clot homogenate, using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Both EH and HV2 were stable in blood and unstable in the liver and kidney homogenates. Eight EH metabolites and eight HV2 metabolites identified as N-terminal fragments were found in the liver and kidney. C-terminal proteolysis is therefore the major metabolic pathway, with serine/cysteine carboxypeptidases and metallocarboxypeptidases being responsible for the degradation of EH and HV2 in the liver and kidney, respectively. EH was cleaved to release HV2 by FXIa. Higher levels of HV2 were produced from EH in the whole-blood clot homogenate, in which the coagulation system was activated compared with those in fresh whole blood. In conclusion, the metabolism of EH and HV2 shares the same cleavage pattern, and EH is transformed into HV2 when the coagulation system is activated, where FXIa is a specific enzyme. Our in vitro study revealed the anticipated prodrug characteristics of EH newly designed as an inactive prodrug of hirudin.

Вплив ураження ацетамінофеном на тлі цукрового діабету типу 2 на зміни показників глутатіонової системи

Introduction. The most important function of the liver in the body is neutralization and destruction of toxic substances. Metabolism and utilization of chemical and biological toxins are carried out by neutralizing the hepatocyte system, followed by the removal of harmful products from the body.The aim of the study – to investigate the effect of acetaminophen on the background of type 2 diabetes mellitus on the main parameters of the glutathione unit of the antioxidant system in rat liver homogenate in time dynamics.Research Methods. The experiments were carried out on white mature rats weighing 180–220 g, contained on a standard ration of the vivarium and free access to water. We conducted 2 series of experiments. In the first, toxic acetaminophen was caused by a single intraventricular injection of acetaminophen in 2 % starch solution at a dose of 1250 mg/kg body weight (1/2 LD50), in the second suspension of acetaminophen in a 2 % starch solution at a dose of 55 mg/kg, which corresponds to the highest therapeutic dose for 7 days. The non-genetic form of experimental type 2 diabetes mellitus was modeled according to the method of Islam S., Choi H. (2007) by a single intraperitoneal injection of a streptozotocin solution (“Sigma”, USA) at a body weight (200±20) g at a rate of 65 mg/kg, which diluted with citrated buffer (pH 4.5) with a preliminary (within 15 minutes) intraperitoneal administration of nicotinamide in a dose of 230 mg/kg. For the control group, rats with the same body weight were administered with a similar volume of solvent (citrate buffer pH 4.5).Results and discussion. Activation of lipid peroximation reactions is one of the fundamental biological mechanisms of damage to biostructures and the development of cellular pathology for the actions of damaging factors of various genesis, especially under the conditions of xenobiotics.Conclusion. Acetaminophen poisoning against type 2 diabetes mellitus causes a significant disruption of compensatory mechanisms, especially the state of the enzyme and non-enzyme links of the antioxidant system.

Inhibitory Effects of Flavonolignans from Silybum marianum (L.) Gaertn (Milk Thistle) on Function of Aldehyde Oxidase and Xanthine Oxidase in Rats

Background: Silybum marianum (L.) Gaertn (Milk thistle) is a medicinal herb fraught with flavonolignans known as silymarin. Methods: We investigated and compared in vitro effects of commercial silibinin (mixture of two diastereomers, silybin A and silybin B) and milk thistle flavonolignans on the kinetic parameters and activities of aldehyde oxidase (AO) and xanthine oxidase (XO) of rat liver. Samples of milk thistle seeds were collected from different locations in Iran and their silymarin extract (contained silibinin flavonolignans) were extracted and quantified. Partially purified hepatic AO and XO were prepared from liver homogenates of rats. AO and XO activities were spectrophotometrically determined in the presence of silibinin (10, 50 and 100 µM) and silymarin extracts (10, 50 and 100 μg/ml) using phenanthridine and xanthine as substrates, respectively. Silymarin extract (100 μg/ml) and silibinin (100 µM) were able to inhibit the rat hepatic XO activities by 65 ± 4 and 70 ± 1%, respectively. Furthermore, the AO activity was reduced to 62 ± 1 and 70 ± 3% in the presence of silymarin extracts and silibinin, respectively. Results and Conclusion: Kinetic studies indicated that AO is inhibited by silibinin in an uncompetitive manner, whereas this flavonolignan was found as a mixed inhibitor of the XO activity. However, compared to the menadione (an AO inhibitor) and allopurinol (the XO inhibitor), silibinin and silymarin extracts had a lower inhibitory effect. Keywords: Silibinin, flavonolignans, aldehyde oxidase (AO), xanthine oxidase (XO), enzyme kinetics, milk thistle.

Novel Metabolically Stable PCA-1/ALKBH3 Inhibitor Has Potent Antiproliferative Effects on DU145 Cells In Vivo.

Novel potent prostate cancer antigen-1 (PCA-1)/alpha-ketoglutarate-dependent dioxygenase alkB homolog 3 (ALKBH3) inhibitors both in vivo and in vivo were designed and evaluated by a stability assay in an S9 mixture, a mixture of rat liver homogenate and co-factors, and oral absorbability assay in rat, as well as enzyme and cell assays, and resulted in the synthesis of a novel potent PCA-1/ALKBH3 inhibitor in vivo. Among them, compound 7l exhibited potent inhibitory activities in a xenograft model bearing DU145 tumor at 10 mg/kg by subcutaneous administration without negative side-effects. This inhibitory activity in vivo was more potent than that of HUHS015 at 32 mg/kg, a known PCA-1/ALKBH3 inhibitor, or docetaxel at 2.5 mg/kg, the drug clinically used for androgen-independent prostate cancer.

Cytosolic β-glucosidase inhibition and renal blood flow suppression are leading causes for the enhanced systemic exposure of salidroside in hypoxic rats.

The promising benefits of salidroside (SAL) in alleviating high altitude sickness boost investigations on its pharmacokinetics and biological activity. However, the transportation and disposition process of SAL under hypoxic conditions has never been explored. The current study was proposed to investigate the pharmacokinetics of SAL in hypoxic rats and to explore the underlying mechanisms for the distinct metabolic fate of SAL under hypoxia. Pharmacokinetic studies on SAL was conducted in both hypoxic and normoxic rats. The transport properties of SAL were investigated on both hypoxic and normoxic Caco-2 monolayer models. Enzymes involved in SAL metabolism were identified and the effects of hypoxia on these enzymes were assessed by real-time PCR, western blotting analyses, and rat liver homogenate incubation. The renal clearance (CLr) of SAL, effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) in both hypoxic and normoxic rats were also determined for renal function assessment. It was found that the systemic exposure of SAL in hypoxic rats was remarkably higher than that in normoxic rats. The barrier function of Caco-2 monolayer was weakened under hypoxia due to the impaired brush border microvilli and decreased expression of tight junction protein. Hepatic metabolism of SAL in hypoxic rats was attenuated due to the reduced activity of cytosolic β-glucosidase (CBG). Moreover, CLr of SAL was reduced in hypoxic rats due to the suppressed ERPF. Our findings suggest the potential need for dose-adjustment of SAL or its structural analogs under hypoxic conditions.

Identification of d-amino acid oxidase and propiverine interaction partners and their potential role in the propiverine-mediated nephropathy

Propiverine, a frequently-prescribed pharmaceutical for the treatment of symptoms associated with overactive bladder syndrome, provoked massive intranuclear and cytosolic protein inclusions in rat proximal tubule epithelium, primarily consisting of the peroxisomal targeting signal 1 (PTS1) containing protein d-amino acid oxidase (DAAO). As this type of nephropathy was also observed for other drugs, the aim was to determine whether propiverine interferes with trafficking and/or import of peroxisomal proteins. To elucidate this, DAAO- and propiverine-specific interaction partners from human HEK293 and rat WKPT cell lines and rat kidney and liver homogenate were determined using co-immunoprecipitation with subsequent nano-ESI-LC-MS/MS analyses. Corroboration of the role of DAAO- and/or propiverine-specific interaction partners in the drug-induced DAAO accumulation was sought via specific immunofluorescence staining of rat kidney sections from control and propiverine-treated rats. Above analyses demonstrated the interaction of propiverine with several protein classes, foremost peroxisomal proteins (DAAO, MFE2, HAOX2) and proteins of the protein quality control system, i.e. chaperones (HSP70 and DnaJ co-chaperones), proteases and proteasomal proteins (regulatory subunits of the 26S proteasome; Rpn1/2). The immunofluorescence analysis revealed mislocalization of many PTS1-proteins (DAAO, CAT, MFE2, ACOX1, EHHADH) in rat renal sections, strongly suggesting that propiverine primarily binds to PTS1 proteins resulting in the formation of PTS1 but not PTS2 or peroxisomal membrane protein (PMP) accumulations. Moreover, chaperones involved in peroxisomal trafficking (HSC70, DnaJB1) and peroxisomal biogenesis factor proteins (PEX3, PEX5, PEX7), also presented with distinct mislocalization patterns. Concomitantly, an increased number of peroxisomes was observed, suggestive of a compensatory mechanism for the presumably suboptimally functioning peroxisomes.Overall, the data presented suggested that propiverine interacts exclusively with DAAO or with a selected number of PTS1 proteins. The consequence of this interaction is the abrogated trafficking and peroxisomal import of PTS1 proteins concomitant with their nuclear and cytosolic accumulation due to inhibited degradation and imbalanced protein homeostasis.

Pharmacokinetic studies of naproxen amides of some amino acid esters with promising colorectal cancer chemopreventive activity

Naproxen (nap) is belonging to Non-steriodal anti-inflammatory drugs (NSAIDs) group of drugs that characterized by their free carboxylic group. The therapeutic activity of nap is usually accompanied by GI untoward side effects. Recently synthesized naproxen amides of some amino acid esters prodrugs to mask the free carboxylic group were reported. Those prodrugs showed a promising colorectal cancer chemopreventive activity. The current study aims to investigate the fate and hydrolysis of the prodrugs kinetically in different pH conditions, simulated gastric and intestinal fluids with pHs of 1.2, 5.5 and 7.4 in vitro at 37 °C. The effect of enzymes on the hydrolysis of prodrugs was also studied through incubation of these prodrugs at 37 °C in human plasma and rat liver homogenates. The pharmacokinetic parameters of selected prodrugs and the liberated nap were studied after oral and intraperitoneal administration in male wistar rats. The results showed the hydrolysis of naproxen amides of amino acid esters to nap through two steps first by degradation of the ester moiety to form the amide of nap with amino acid and the second was through the degradation of the amide link to liberate nap. The two reactions were followed and studied kinetically where K1 and K2 (rate constants of degradation) is reported. The hydrolysis of prodrugs was faster in liver homogenates than in plasma. The relative bioavailability of the liberated nap in vivo was higher in case of prodrug containing ethyl glycinate moiety than that occupied l-valine ethyl ester moiety. Each of nap. prodrugs containing ethyl glycinate and l-valine ethyl ester moieties appears promising in liberating nap, decreasing direct GI side effect and consequently their colorectal cancer chemopreventive activity.

Hepatospecific signs of disorders in the free radical oxidation-antioxidation defense system in rats with diabetes mellitus aggravated by cerebral ischemia-reperfusion

Cerebral hypoxia results in considerable pathological-histological changes in the internal organs with disorders of their functional state. In case of diabetes mellitus metabolic disorders cause liver damage as well, therefore diabetes aggravated by cerebral ischemia-reperfusion should logically make morphofunctional changes in this organ worse.Objective of the study: to examine the signs of oxidative and nitrosative stress in the liver of rats with diabetes mellitus aggravated by cerebral ischemia-reperfusion.Material and methods. The content of the products of lipid peroxide oxidation, oxidative protein modification, metabolites of nitrogen oxide and activity of antioxidant enzymes were investigated in the liver homogenates of rats. Diabetes mellitus was simulated by means of a single intraperitoneal injection of streptozotocin (Sigma, USA, 60 mg/kg). The results were assessed after 20-minute carotid ischemia with one hour reperfusion and on the 12th day of post-ischemic period. Results. According to the changes in the content of lipid peroxidation products and activity of antioxidant enzymes 20-minute carotid ischemia with one hour reperfusion results in the depression in the lipoperoxidation-antioxidation defense system. On the 12th day of the experiment the content of diene conjugates in this organ increases against the background of an increased activity of superoxide dismutase and glutathione peroxidase which, in general, is indicative of a compensatory character of the reaction of the lipid peroxidation-antioxidant defense system. The indices of oxidation protein modification and nitrogen oxide metabolism during the early post-ischemic period remain without changes in the liver of animals from this group, and they increase on the 12th day of the experiment, which is indicative of the availability of oxidative and nitrosative stress during this period. In the liver of animals with diabetes mellitus the reaction of all the mentioned indices is absent both during early and late post-ischemic periods. Conclusion. The lack of the signs of lipid peroxidation, protein oxidative modification, nitrogen oxide metabolism and activity of antioxidant defense in the liver of animals with diabetes mellitus both during early and late post-ischemic periods is indicative of areactivity of these biochemical indices concerning cerebral ischemia-reperfusion.

Change of energy supply oxidation indices changes in rats with type 2 diabetes mellitus and acetaminophen toxic lesions

Introduction. Acetaminophen is an effective and safe drug for emergency usage, but there are contraindications for its usage. Diabetes mellitus is an endocrine disease, which caused by the absolute or relative deficiency of pancreas hormone (insulin).The aim of the study – to learn the change of energy supply oxidation indices in animals with type 2 diabetes mellitus and acetaminophen toxic lesions in time dynamics.Research Methods. We conducted two series of experiments. In the first series toxic lesion was caused by a single intragastric administration of acetaminophen suspension in 2 % starch solution to animals in a dose of 1250 mg/kg (1/2 LD50). In the second series the suspension of acetaminophen in 2 % starch solution in a dose of 55 mg/kg was given. Non-genetic form of experimental type 2 diabetes mellitus was modeled by a single intraperitoneal administration of streptozotocin solution in doses 65 mg/kg, which was diluted by citrate buffer (pH 4.5) with the previous intraperitoneal nicotinamide administration in doses of 230 mg/kg. Rats, which were given the same amount of solvent (citrate buffer pH 4.5), were used as the control group.Results and Discussion. Cytochrome oxidase and succinate dehydrogenase activity decreased in rat liver homogenate under the influence of acetaminophen with type 2 diabetes mellitus throughout the experiment.Conclusions. Acetaminophen administration to rats with type 2 diabetes mellitus causes significant violations of energy supply oxidation.

Silicone dioxide nano-particles enhance toxicity of lead on oxidative and nitro-oxidative stress

Introduction. Nanoparticles are widely used in scientific research, industry and medicine. The established capability of nanoparticles to increase the transport of chemicals and drugs into cells and through the body barriers makes the possibility of potentiating the chemical contaminants toxicity in case of their simultaneous intake an urgent matter.The aim of the study – to learn the effect of silicon dioxide nanoparticles on the ability of chemical lead acetate toxicant to cause oxidative and nitro-oxidative stress in blood serum and liver of experimental rats.Research Methods. Experiments were conducted on 40 white outbred male rats, 150–160 g in weight, which were divided into 4 groups. Animals of the group (control) 1 were daily administered with saline solution intragastrically. The rats of the group 2 were administered with colloidal solution of silicon dioxide nanoparticles in a dose of 50 mg/kg of body weight. Animals of the group 3 were injected with lead acetate in aqueous solution in a dose of 20 mg/kg of body weight (expressed as lead), the group 4 – with solution of silicon dioxide nanoparticles with lead acetate daily during 3 weeks at the same doses. The total activity of NO-synthase, catalase, superoxide dismutase, NOx content, thiobarbituric acid reactive substances, oxidized modified proteins, reduced glutathione, ceruloplasmin and total serum antioxidant activity were determined in serum and liver. The obtained parameters were statistically processed.Results and Discussion. It was proved that silicon dioxide nanoparticles did not influence the studied parameters considerably. The administration of lead acetate to rats caused significant changes of all indices. However, the maximum changes of the parameters were evidenced in the group of animals in cases of simultaneous administration of silicon dioxide nanoparticles and lead acetate. In that case, the content of thiobarbituric acid reactive substances, NOx, oxidized modified proteins, reduced glutathione, and superoxide dismutase activity in blood serum and liver homogenate of rats varied significantly compared with the parameters of the group of animals that were administered with the chemical toxicant only.Conclusion. Silicon dioxide nanoparticles enhance the capability of the chemical lead acetate toxicant to cause oxidative and nitro-oxidative stress in blood serum and liver of the experimental rats.

African locust bean (Parkia biglobosa, Jacq Benth) leaf extract affects mitochondrial redox chemistry and inhibits angiotensin-converting enzyme in vitro

BackgroundParkia biglobosa leaf has popular ethnomedicinal use in tropical Africa. However, little is known about its molecular biological effects. This study sought to investigate the in vitro antioxidant activity, angiotensin-I-converting enzyme (ACE) inhibition and effects of aqueous-methanolic extract of P. biglobosa leaf (PBE) on mitochondrial membrane potential and reactive oxygen species (ROS) generation.MethodsAntioxidant activity was determined by extract’s DPPH. (1,1-diphenyl-2-picrylhydrazyl radical), ABTS.+ [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation] scavenging ability, reducing property and propensity to inhibit lipid peroxidation induced by prooxidants (FeSO4/sodium nitroprusside, SNP) in isolated rat tissue preparations. Determination of angiotensin-converting enzyme (ACE) inhibition was based on the hydrolysis of N-hippuryl-His-Leu hydrate (HHL) by the enzyme. Subsequently, the effects of PBE on toxicant-induced mitochondrial ROS formation and basal membrane potential (∆Ψm) were determined by 2′, 7′-dichlorodihydrofluorescin (DCFH) oxidation and safranine fluorescence respectively.ResultsPBE significantly reduced ferric ions (P < 0.001), scavenged DPPH (EC50 = 98.33 ± 1.0 μg/mL) and ABTS (EC50 = 45.30 ± 0.1) radicals, with moderate Fe2+- chelating effect (40%). In rat liver and brain homogenates respectively, PBE prevented membrane peroxidation induced by FeSO4 (EC50: 75.87 ± 2.1 μg/mL and 89.34 ± 2.5 μg/mL) and SNP (EC50: 28.10 ± 1.6 μg/mL and 17.25 ± 0.78 μg/mL). The extract’s inhibition of ACE (IC50 = 51.30 ± 5.1 μg/mL) and mild depolarization of isolated liver mitochondria membrane potential were concentration-dependent. Finally, PBE was more effective than catechin in attenuating calcium and SNP-induced surge in mitochondrial ROS generation.ConclusionParkia biglobosa leaf exhibits considerable ACE inhibitory effect, antioxidant activity and affects mitochondrial redox chemistry. These present findings also justify the ethnobotanical applications of the plant in the indigenous system of medicine.