Antioxidants play a crucial role in the treatment of liver pathologies, given that oxidative stress is involved in the pathogenesis of many hepatic diseases. This study aimed to investigate the pharmacodynamic and pharmacokinetic properties of the antioxidant 2,6-diisobornyl-4-methylphenol (IBP) in a rat model of carbon tetrachloride (CCl4)-induced liver injury. The introduction of IBP resulted in a 1.4- to 2-fold decrease in serum hepatic enzyme levels, a 25% and 18% rise in glutathione peroxidase and superoxide dismutase concentrations, respectively, and a 14% reduction in hepatic catalase activity compared with the negative control. Treated animals exhibited a 45% reduction in malondialdehyde (a marker of oxidative stress) and an 18% decrease in interleukin-6 levels relative to controls. The compound mitigated CCl4-induced liver damage and promoted restoration of liver function. Liver pathology affected the plasma exposure of IBP after a single administration, but pharmacokinetics normalized following repeated dosing. Bioavailability was 60% after a single dose and increased to 119% after multiple administrations. IBP demonstrated significant hepatoprotective effects in CCl4-induced liver injury, mitigating lipid peroxidation, inflammation, and necrosis. The initial reduction in systemic exposure following a single dose in pathological conditions may be attributed to impaired absorption and elevated metabolic consumption due to oxidative stress.

A new approach has been developed to study the pharmacokinetics of 2,6-diisobornyl-4-methylphenol, a phenolic antioxidant, after intragastric administration at a dose of 10 mg/kg to male Wistar rats with ischemia/reperfusion liver injury. The control group consisted of rats without pathology. A catheter previously implanted into the jugular vein of the animals, allowed repeated blood sampling and monitoring of the pharmacokinetic profile of the substance in each animal. Pharmacokinetic studies usually involve healthy animals, but the ischemia/reperfusion injury of the liver disrupted its functions, potentially altering drug metabolism and pharmacokinetics. Analysis of actual blood plasma samples confirmed the effectiveness of the proposed approach: changes in the pharmacokinetics of the phenolic antioxidant were revealed during liver ischemia/reperfusion injury in rats.

IBP (2,6-diisobornyl-4-methylphenol) is a camphene derivative with unique pharmacological properties and low toxicity. It exhibits pronounced antioxidant and membrane-protective effects, making it a promising cardio- and neuroprotector.The aim of the study was investigating the pharmacokinetics of IBP in rats after intravenous (1 mg/kg) and oral administration at three doses (10, 25, 50 mg/kg). Specifically, we focused on assessing the bioavailability and dose proportionality following oral administration.Blood samples were collected via a jugular vein catheter, and plasma samples were analysed using a validated HPLC-MS/MS method. The calculation of pharmacokinetic parameters was performed by both non-compartmental and compartmental approaches. The proposed dosage form for intravenous administration was a multicomponent mixture containing N-methyl-2-pyrrolidone.Concentration of IBP in the body after intravenous administration decreased over time, exhibiting bi-exponential decay kinetics. IBP reached peak concentrations immediately and was rapidly distributed into the peripheral compartment after intravenous administration. The systemic exposure after oral administration was proportional to the dose. The calculated absolute oral bioavailability of IBP was no more than 20%.The value of the average half-life of IBP after intravenous administration exceeded similar values after oral administration by 1.5-1.6 times.

The neuroprotective activity of tryptanthrin and its oxime was compared in male Wistar rats with a model of intraluminal occlusion of the middle cerebral artery. Neurobehavioral tests were performed 4, 24, and 48 h after focal cerebral infarction (FCI) using a modified neurological severity score (mNSS); additionally, the horizontal stability test, the plantar sensitivity test of the fore and hind limbs, holding on the tilted cage top test, and negative geotaxis test were performed. The size of FCI and the severity of brain tissue swelling were examined on day 2 after occlusion. Tryptanthrin and its oxime were administered at a dose of 10 mg/kg intraperitoneally during FCI, then daily for 2 days. In the control group, the mean score of neurological deficit remained at a high level for 2 days. FCI size was 43.8±3.4

1.The dose proportionality and bioavailability of the potential anti-inflammatory and neuroprotec-tive JNK inhibitor 11H-indeno[1,2-b]quinoxalin-11-one oxime (IQ-1) were evaluated by comparing pharmacokinetic parameters after single oral (25, 50 and 100mg/kg) and intravenous (1mg/kg) IQ-1 administration in rats.2. IQ-1 and its major metabolite ketone 11H-indeno[1,2-b]quinoxalin-11-one (IQ-18) were isolated from plasma samples by liquid-liquid extraction. IQ-1 (E-isomer) and IQ-18 were simultaneously quantified in plasma by the validated method of liquid chromatography with triple quadrupole mass spectrometry (HPLC-MS/MS).3. The absolute bioavailability of IQ-1 was <1.5%. Cmax values were 24.72 +/- 4.30, 25.66 +/- 7.11 and 37.61 +/- 3.53ng/mL after single oral administration of IQ-1 at doses of 25, 50 and 100mg/kg, respectively. IQ-1 exhibited dose proportionality at 50-100mg/kg dose levels, whereas its pharma-cokinetics was not dose proportional over the range of 25-50mg/kg. IQ-18 demonstrated the invariance of the dose-normalized Cmax.4.In this study we systematically elucidated the absorption characteristics of IQ-1 in rat gastrointes-tinal tract and provided better understanding of IQ-1 pharmacology for the future development of a new formulations and therapeutic optimisation.

In experiments on Wistar rats, the effect of a new selective JNK inhibitor tryptanthrin oxime (TR-Ox) on parameters of systemic hemodynamics, cardiohemodynamics, and post-infarction fibrosis was studied 4 months after acute myocardial ischemia (1 h) followed by reperfusion. TR-Ox was administered intraperitoneally at a dose of 12 mg/kg 20 min before reperfusion, and then once a day for the next 4 days. Administration of TR-Ox to animals in the acute phase of myocardial infarction contributed to more complete preservation of myocardial viability in the delayed period: a relative increase of muscle elements proportion in the scar, a decrease in the formation of connective tissue areas with complete and >50% replacement of the myocardium, and deceleration of fibrotic scarring in myocardium areas distant from the focus of injury, resulting in improved systolic and diastolic myocardial function. Four months after myocardial infarction, significant improvement in systemic hemodynamics and cardiohemodynamics parameters was observed in the group treated with TR-Ox: stroke volume, cardiac output, left ventricular systolic pressure, maximum rates of left ventricle pressure rise and fall significantly increased and the left ventricle end-diastolic pressure decreased in comparison with the corresponding parameters in the control group.

The effect of a new JNK inhibitor IQ-1 (11 H -indeno[1,2- b ]quinoxalin-11-one oxime) was studied in male Wistar rats in a model of acute myocardial ischemia/reperfusion. Area at risk and myocardial infarct zones were studied in two series of experiments: 16 h after a single dose of IQ-1 (25 mg/kg intraperitoneally during cardiac ischemia) and on day 5 after its course administration (25 mg/kg intraperitoneally during cardiac ischemia and daily over 4 days). On day 5 after ischemia/reperfusion, cardiodynamic indicators were also studied: systolic, end-diastolic, and minimum pressure in the left ventricle, stress—time index, as well as the maximum rates of pressure rise and fall in the left ventricle (+dP/dt max and -dP/dt max ). In 16 h after ischemia/reperfusion, the infarct area in the control was 24±2% of the total area of the sections, while after administration of IQ-1 this parameter was 14±1% ( p <0.05). On day 5, the infarct area in the control group was 25±1% of the total area of myocardial sections. A course of IQ-1 administration led to a significant reduction in the infarct area to 10±2% of the total area of myocardial slices. Course administration of IQ-1 led to improvement in contractile function and weakening of the diastolic dysfunction of the left ventricle: systolic pressure in the left ventricle increased by 20%, +dP/dt max by 23%, voltage—time index by 12%, -dP/dt max by 43%, and the minimum pressure in the left ventricle decreased by 3.4 times.

We studied the radical-binding and antioxidant activities of the alkaloid tryptanthrin (TR) and its new synthetic derivative tryptanthrin oxime (TR-Ox), as well as the cytoprotective activity of TR-Ox under conditions of oxidative stress. The antiradical activity of TR-Ox was revealed in the test of binding with stable chromogen radical 2,2-diphenyl-1-picrylhydrazyl and in the superoxide radical generation test (riboflavin photoreduction reaction with detection by NBT reduction). TR-Ox was inferior to ionol and dihydroquercetin by the antiradical activity. In these tests, TR did not exhibit antiradical activity. TR-Ox did not show iron-chelating activity (in the test with the formation of the o-phenanthroline-Fe2+ complex and its destruction in the presence of chelating agents). In brain homogenate, TR-Ox significantly reduced the increase in spontaneous chemiluminescence. Under conditions of oxidative stress induced by 15 mM H2O2 in the SH-SY5Y neuroblastoma cell culture, TR-Ox exhibited cytoprotective activity and increased the number of viable cells.

We studied the action of a new indolinone derivative GRS, acetylsalicylic acid (ASA), and their combination on platelet aggregation, vasodilatory endothelial function, neurological status, and cerebral infarction area in experimental focal cerebral ischemia/reperfusion in rats. GRS compound (10 mg/kg), ASA (10 mg/kg), and their combination in the same doses were administered orally once a day as a suspension in 1% starch solution over 5 days after pathology modeling. Sham-operated and control animals were administered 1% starch solution. On day 5 after pathology modeling, platelet aggregation and brain damage area were studied in a half of rats in each group, and the vasodilatory function of the endothelium was studied in the other half. Neurological deficit was assessed 4 h and 1, 3, and 5 days after pathology modeling. GRS compound and ASA equally effectively prevent platelet aggregation and the development of neurological deficit in rats. GRS compound restores the vasodilatory effects of the endothelium, but only ASA contributes to reduction of the cerebral infarction area. In case of combined administration, GRS and ASA do not exhibit synergy in their antiaggregant effect.

Activation of c-Jun N-terminal kinases (JNKs) is involved in myocardial injury, left ventricular remodeling (LV), and heart failure (HF) after myocardial infarction (MI). The aim of this research was to evaluate the effects of a selective JNK inhibitor, 11H-indeno [1,2-b]quinoxalin-11-one oxime (IQ-1), on myocardial injury and acute myocardial ischemia/reperfusion (I/R) in adult male Wistar rats. Intraperitoneal administration of IQ-1 (25 mg/kg daily for 5 days) resulted in a significant decrease in myocardial infarct size on day 5 after MI. On day 60 after MI, a significant (2.6-fold) decrease in LV scar size, a 2.2-fold decrease in the size of the LV cavity, a 2.9-fold decrease in the area of mature connective tissue, and a 1.7-fold decrease in connective tissue in the interventricular septum were observed compared with the control group. The improved contractile function of the heart resulted in a significant (33%) increase in stroke size, a 40% increase in cardiac output, a 12% increase in LV systolic pressure, a 28% increase in the LV maximum rate of pressure rise, a 45% increase in the LV maximum rate of pressure drop, a 29% increase in the contractility index, a 14% increase in aortic pressure, a 2.7-fold decrease in LV end-diastolic pressure, and a 4.2-fold decrease in LV minimum pressure. We conclude that IQ-1 has cardioprotective activity and reduces the severity of HF after MI.

The activation of c-Jun N-terminal kinase (JNK) plays an important role in stroke outcomes. Tryptanthrin-6-oxime (TRYP-Ox) is reported to have high affinity for JNK and anti-inflammatory activity and may be of interest as a promising neuroprotective agent. The aim of this study was to investigate the neuroprotective effects of TRYP-Ox in a rat model of transient focal cerebral ischemia (FCI), which involved intraluminal occlusion of the left middle cerebral artery (MCA) for 1 h. Animals in the experimental group were administered intraperitoneal injections of TRYP-Ox 30 min before reperfusion and 23 and 47 h after FCI. Neurological status was assessed 4, 24, and 48 h following FCI onset. Treatment with 5 and 10 mg/kg of TRYP-Ox decreased mean scores of neurological deficits by 35–49 and 46–67% at 24 and 48 h, respectively. At these doses, TRYP-Ox decreased the infarction size by 28–31% at 48 h after FCI. TRYP-Ox (10 mg/kg) reduced the content of interleukin (IL) 1β and tumor necrosis factor (TNF) in the ischemic core area of the MCA region by 33% and 38%, respectively, and attenuated cerebral edema by 11% in the left hemisphere, which was affected by infarction, and by 6% in the right, contralateral hemisphere 24 h after FCI. TRYP-Ox reduced c-Jun phosphorylation in the MCA pool at 1 h after reperfusion. TRYP-Ox was predicted to have high blood–brain barrier permeability using various calculated descriptors and binary classification trees. Indeed, reactive oxidant production was significantly lower in the brain homogenates from rats treated with TRYP-Ox versus that in control animals. Our data suggest that the neuroprotective activity of TRYP-Ox may be due to the ability of this compound to inhibit JNK and exhibit anti-inflammatory and antioxidant activity. Thus, TRYP-Ox may be considered a promising neuroprotective agent that potentially could be used for the development of new treatment strategies in cerebral ischemia.

The specific JNK inhibitor and NO donor 11H-indeno[1,2-b]quinoxalin-11-one oxime (IQ-1) demonstrated pronounced neuroprotective properties in an in vivo model of ischemic stroke in rats. The pharmacokinetic behavior of IQ-1 was studied in two animal species (rats, rabbits) after intravenous administration in a dose of 1 mg/kg. IQ-1 concentrations in venous blood plasma were measured by the liquid chromatography-tandem mass spectrometry method. The pharmacokinetics of IQ-1 was adequately described by the two-compartmental model. The calculated C0 for IQ-1 in rabbit and rat plasma were 2239.83±1229.55 and 1552.50±182.23 ng/ml, respectively. Two animal species are characterized by extensive tissue distribution of IQ-1 (Vss exceeded the total body water in rabbits and rats by 3.6 and 5.6 times, respectively) and high clearance values (88-94% of hepatic blood flow).

The effect of p-tyrosol on the main hemodynamic parameters and contractile function of the heart was studied and a morphometric assessment of left-ventricular remodeling was performed in Wistar rats 2 months after acute 1-h myocardial ischemia followed by reperfusion. p-Tyrosol in a dose of 20 mg/kg was injected intraperitoneally 5 times: 20 min before the start of reperfusion, 4 h after the start of reperfusion, and then once a day over the next 3 days. Administration of p-tyrosol to animals in the acute period of myocardial infarction slowed down the formation of systolic and diastolic myocardial dysfunction, improved the pumping function of the heart, maintained the hemodynamic parameters at a significantly higher level, and reduced left-ventricular remodeling in the late period of myocardial infarction. In 2 months after acute myocardial ischemia modeling, the dimensions of the left-ventricular cavity, the area of the postinfarction focus, and the area of connective tissue in rats treated with p-tyrosol were significantly lower than in the control group. In the group treated with p-tyrosol, no anterior left-ventricular wall aneurysms were found.

New antithrombotic drug GRS, a soluble guanylate cyclase stimulator, after repeated administration in a dose of 10 mg/kg alleviates the symptoms of endothelial dysfunction in rats with myocardial infarction; it restores antiplatelet activity of the blood vessel wall and vasodilatory function of the endothelium without producing significant effect on endothelium-independent vasodilation. GRS also has direct antiaggregant and antihypertensive effects in therapeutic doses. The obtained data suggest that GRS can be therapeutically useful in patients with cardiovascular diseases accompanied by endothelial dysfunction.

The c-Jun N-terminal kinases (JNKs) regulate many physiological processes, including inflammatory responses, morphogenesis, cell proliferation, differentiation, survival, and cell death. Therefore, JNKs represent attractive targets for therapeutic intervention. In an effort to develop improved JNK inhibitors, we synthesized the lithium salt of 11H-indeno[1,2-b]quinoxaline-11-one oxime (IQ-1L) and evaluated its affinity for JNK and biological activity in vitro and in vivo. According to density functional theory (DFT) modeling, the Li+ ion stabilizes the six-membered ring with the 11H-indeno[1,2-b]quinoxaline-11-one (IQ-1) oximate better than Na+. Molecular docking showed that the Z isomer of the IQ-1 oximate should bind JNK1 and JNK3 better than (E)-IQ-1. Indeed, experimental analysis showed that IQ-1L exhibited higher JNK1-3 binding affinity in comparison with IQ-1S. IQ-1L also was a more effective inhibitor of lipopolysaccharide (LPS)-induced nuclear factor-κB/activating protein 1 (NF-κB/AP-1) transcriptional activity in THP-1Blue monocytes and was a potent inhibitor of proinflammatory cytokine production by MonoMac-6 monocytic cells. In addition, IQ-1L inhibited LPS-induced c-Jun phosphorylation in MonoMac-6 cells, directly confirming JNK inhibition. In a rat model of focal cerebral ischemia (FCI), intraperitoneal injections of 12 mg/kg IQ-1L led to significant neuroprotective effects, decreasing total neurological deficit scores by 28, 29, and 32% at 4, 24, and 48 h after FCI, respectively, and reducing infarct size by 52% at 48 h after FCI. The therapeutic efficacy of 12 mg/kg IQ-1L was comparable to that observed with 25 mg/kg of IQ-1S, indicating that complexation with Li+ improved efficacy of this compound. We conclude that IQ-1L is more effective than IQ-1S in treating cerebral ischemia injury and thus represents a promising anti-inflammatory compound.

Introduction . The article presents the results of studying the antithrombotic activity of a novel drug, a soluble guanylate cyclase stimulator (codename – GRS), in experimental models of arterial and venous thrombosis and thromboembolism. Aim . Study the antithrombotic action of GRS compound in comparison with clopidogrel and rivaroxaban in the following models: arterial thrombosis induced by iron chloride application to carotid artery wall in rats; thromboembolism induced by intravenous administration of thrombin solution in mice; venous thrombosis induced by the ligature of inferior vena cava in rats. Materials and methods . Arterial thrombosis was modelled in rats by applying a pad soaked in iron chloride (FeCl 3 ) to the carotid artery, GRS compound was administered orally in median effective dose of 10 mg/kg once 3 hours before pad application. Blood flow in carotid arteries and blood clot mass were registered. Thromboembolism was induced in mice by intravenous administration of thrombin solution, GRS in dose 10 mg/kg or the reference drug clopidogrel were administered once orally daily for 3 days. Animal mortality, survival time and blood clot size were registered. Venous thrombosis was induced in rats by the ligature of inferior vena cava below renal veins, GRS in dose 10 mg/kg, reference drug rivaroxaban in 5 mg/kg dose or their combination in these doses were administered once orally 1 hour before vein ligature. The mass of dry and wet blood clots was registered. Results and discussion . In arterial thrombosis model GRS compound in 10 mg/kg, administered 3 hours before iron chloride application, increased the time to blood flow cessation in the carotid artery by 35 % and reduced the frequency of complete artery occlusion by 2 times compared to the control group ( р < 0.05). 60 min after arterial thrombosis modelling complete occlusion was observed in 28 % of animals in GRS group and in 75 % of control animals, while after 24 hours the occlusion was observed in 14 % of animals in GRS group and in 50 % of control group animals ( p < 0.05). In thrombin-induced thromboembolism model in mice GRS did not reduce the size of blood clots in pulmonary vessels, while clopidogrel reduced it by 48 %. In GRS group 80 % of animals died of thrombosis, compared to 30 % in clopidogrel group and 90 % in the control group. In ligature-induced venous thrombosis in rats GRS after single oral administration reduced the mass of dry blood clot, being as potent as rivaroxaban. Combined administration of GRS and rivaroxaban did not enhance their antithrombotic action. Conclusion . GRS after single oral administration in 10 mg/kg dose had potent antithrombotic action in models of arterial and venous thrombosis in rats, while not preventing pulmonary vessel thrombosis in mice after thrombin administration. Therapeutic action of GRS in experimental venous thrombosis was as potent as that of rivaroxaban. Antithrombotic action of GRS compound results not only from its antiplatelet action, but also from the alleviation of endothelial dysfunction in arteries and veins.

Aim. To investigate anti-ischemic and antiarrhythmic activity of Dibornol in conditions of multiple transitory ischemia of myocardium from in vivo experiments with rats. Material and Methods. The experiment was performed on male Wistar rats with a model of myocardial ischemia caused by 5-time 3-minute occlusions of the left coronary artery, followed by 15-minute reperfusion periods. Rats of the experimental group received Dibornol 10 mg/kg intragastrically once for 4 days; control animals received an equivalent volume of 1% starch mucus. On the ECG, the magnitudes of the ST segment elevation were determined for minutes 1, 2, and 3 of each episode of ischemia and for minutes 5, 10, and 15 of reperfusion; the nature and duration of ventricular arrhythmias were determined as well. Results. In the control group, the ST segment was elevated during all five episodes of ischemia. During reperfusion periods, a decrease in the elevation of the ST segment was detected, but no normalization occurred. Ischemic and reperfusionrelated ventricular arrhythmias were observed in the rats of the control group. Mortality in the control group reached 67% (6 animals out of 9). In the experimental group, in animals receiving Dibornol at a dose of 10 mg/kg, the occlusion of the left coronary artery was associated only with a slight elevation of the ST segment and its rapid recovery during reperfusion. Magnitudes of the ST segment elevation were significantly lower than the corresponding control values during all the episodes of ischemia. During reperfusion periods, the differences with the control group were more significant during the first to fourth periods and at minute 15 of the fifth reperfusion period. The death rate in the experimental group (1 animal out of 9) was significantly lower relative to the corresponding value in the control group. Conclusion. The course preventive use of Dibornol in multiple myocardial ischemia/reperfusion had significant anti-ischemic and antiarrhythmic effects during reperfusion periods and significantly increased the survival rate in animal models.

A novel specific inhibitor of c-Jun N-terminal kinase, 11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S), has a high affinity to JNK3 compared to JNK1/JNK2. The aim of this work was to study the mechanisms of neuroprotective activity of IQ-1S in the models of reversible focal cerebral ischemia (FCI) in Wistar rats. The animals were administered with an intraperitoneal injection of IQ-1S (5 and 25 mg/kg) or citicoline (500 mg/kg). Administration of IQ-1S exerted a pronounced dose-dependent neuroprotective effect, not inferior to the effects of citicoline. Administration of IQ-1S at doses of 5 and 25 mg/kg reduced the infarct size by 20% and 50%, respectively, 48 h after FCI, whereas administration of citicoline reduced the infarct size by 34%. The administration of IQ-1S was associated with a faster amelioration of neurological status. Control rats showed a 2.0-fold increase in phospho-c-Jun levels in the hippocampus compared to the corresponding values in sham-operated rats 4 h after FCI. Administration of IQ-1S at a dose of 25 mg/kg reduced JNK-dependent phosphorylation of c-Jun by 20%. Our findings suggest that IQ-1S inhibits JNK enzymatic activity in the hippocampus and protects against stroke injury when administered in the therapeutic and prophylactic regimen in the rat model of FCI.

(1) Background: Although myelin disruption is an integral part of ischemic brain injury, it is rarely the subject of research, particularly in animal models. This study assessed for the first time, myelin and oligodendrocyte loss in a three-vessel model of global cerebral ischemia (GCI), which causes hippocampal damage. In addition, we investigated the relationships between demyelination and changes in microglia and astrocytes, as well as oligodendrogenesis in the hippocampus; (2) Methods: Adult male Wistar rats (n = 15) underwent complete interruption of cerebral blood flow for 7 min by ligation of the major arteries supplying the brain or sham-operation. At 10 and 30 days after the surgery, brain slices were stained for neurodegeneration with Fluoro-Jade C and immunohistochemically to assess myelin content (MBP+ percentage of total area), oligodendrocyte (CNP+ cells) and neuronal (NeuN+ cells) loss, neuroinflammation (Iba1+ cells), astrogliosis (GFAP+ cells) and oligodendrogenesis (NG2+ cells); (3) Results: 10 days after GCI significant myelin and oligodendrocyte loss was found only in the stratum oriens and stratum pyramidale. By the 30th day, demyelination in these hippocampal layers intensified and affected the substratum radiatum. In addition to myelin damage, activation and an increase in the number of microglia and astrocytes in the corresponding layers, a loss of the CA1 pyramidal neurons, and neurodegeneration in the neocortex and thalamus was observed. At a 10-day time point, we observed rod-shaped microglia in the substratum radiatum. Parallel with ongoing myelin loss on the 30th day after ischemia, we found significant oligodendrogenesis in demyelinated hippocampal layers; (4) Conclusions: Our study showed that GCI-simulating cardiac arrest in humans-causes not only the loss of pyramidal neurons in the CA1 field, but also the myelin loss of adjacent layers of the hippocampus.