The new conjugate compound pyrrolylcarnosine was synthesized from the natural antioxidant carnosine and the aromatic five-membered nitrogen heterocycle pyrrole. The synthesis of pyrrolylcarnosine was described. Its physicochemical properties and biological activity in various oxidative stress models were evaluated. The results showed that pyrrolylcarnosine was characterized by resistance to hydrolysis by serum carnosinase and exhibited high antioxidant activity in model experiments. It had a neuroprotective effect under oxidative stress induced by the neurotoxin AAPH, increasing the viability of a differentiated culture of human neuroblastoma SH-SY5Y and protecting it from death. In general, the results indicated creation of a new drug based on pyrrolylcarnosine was promising.

На основе природного антиоксиданта карнозина и ароматического пятичленного азотистого гетероцикла пиррола нами было синтезировано новое конъюгированное соединение — пирролилкарнозин. В данном исследовании описан синтез пирролилкарнозина, дана оценка его физико-химических свойств и биологической активности в различных моделях окислительного стресса. Результаты проведенного исследования показали, что пирролилкарнозин характеризуется устойчивостью к гидролизу сывороточной карнозиназой, высокой антиоксидантной активностью в модельных экспериментах и оказывает нейропротекторное действие в условиях индукции окислительного стресса нейротоксином ААРН, повышая жизнеспособность дифференцированной культуры нейробластомы человека SH-SY5Y и защищая ее от гибели. В целом, полученные результаты указывают на перспективность создания нового лекарственного средства на основе пирролилкарнозина.

The search for effective pharmaceutical agents which possess high antiaggregant and antioxidant activity, and simultaneously, lack negative side effects, is a highly relevant task for modern science. In this regard, we evaluated the antiplatelet activity of a new conjugated compound from acetylsalicylic acid and carnosine—salicyl-β-alanil-L-histidine (salicyl-carnosine, SC) and investigate the antioxidant activity of SC in an in vitro model of Fe 2+ -induced chemoluminiscence of low and very low density lipoproteins, acquired from blood of patients with chronic cerebrovascular diseases (CCVD). The acquired results indicate that the effectiveness of SC in reducing ADP-induced thrombocyte aggregation in vitro is comparable to that of acetylsalicylic acid. At the same time, carnosine and salicylic acid failed to demonstrate any significant antiaggregant effect. All investigated compounds had a similar effect on lipid hydro-peroxides levels, and effectively decreased them in a range of concentrations from 50 to 500 µM. The observed antioxidant activity of compounds, occurred proportionately to their concentration. In conclusion, SC possesses both antiaggregant and antioxidant activity, which is maintained in CCVD patient blood samples in vitro. This new compound has the potential to become an effective pharmaceutical agent for treating cerebrovascular disease.

In this study, the effects of chronic administration of low doses of the mitochondrial neurotoxins MPTP (4 mg/kg for 23 days) and rotenone (4 mg/kg for 7 days) in CD-1 mice were compared. A comparative assessment of neurochemical and behavioral changes at the pre-symptomatic stage of parkinsonism is given in these two different models side-by-side. We identified distinct motor and postural disorders in mice on the 23rd day of experiments when the animals received a total MPTP dose of 92 mg/kg. In animals treated with rotenone, similar motor disorders developed more rapidly, manifesting themselves by the 7th day of the experiment, when the cumulative administered dose was 28 mg/kg. The present study focused on the dynamics of neurochemical changes which precede the onset of motor symptoms: in MPTP-treated mice up to the 23rd day and in rotenone-treated mice up to the 7th day. We showed the similar dynamics of neurodegeneration in the SNpc—the rapid decrease in the number of neurons during the first 7 days in MPTP-treated mice (by 36%) and rotenone-treated mice (by 43%). However, Rotenone, unlike MPTP, did not cause a decrease in striatal dopamine levels by the time of motor impairments. This reveals a key difference in the effects of these toxins on the dopaminergic system. A transient increase in the serotonin content in the striatum of mice at the early stages of rotenone administration was noted. A significant decrease in endogenous antioxidant activity was observed as a side effect of both toxins, in line with the duration of toxin administration. Histochemical analysis revealed the different time dynamics of cytochrome-c-oxidase activity decrease, with more early and pronounced effects in the MPTP-treated mice. Based on the acquired results it can be concluded that MPTP, used at low doses, is a more reliable neurotoxin when compared to rotenone in inducing progressive nigrostriatal lesion and pre-symptomatic parkinsonism. Despite them both targeting the electron transport chain, the mechanisms behind their systemic action differ.

Abstract—Oxidative stress (OS) plays an important role in the cascade of events leading to the degeneration of dopaminergic neurons in Parkinson’s disease (PD). Oxidative damage to proteins and nucleic acids contributes to this process. Reactive oxygen and nitrogen species cause protein nitration and the formation of the stable compound 3-nitrotyrosine (3-NT), which characterizes the development of nitrosyl stress, as well as nucleic acids which form the product of DNA oxidation, 8-hydroxy-2-deoxyguanosine (8-OH-dG). Protein and DNA oxidation products are present in the biological fluids of PD patients, however, data on their quantitative content depending on the severity of the disease are contradictory. The aim of this work was to compare the level of products of oxidative damage of proteins and DNA in the blood of patients with PD at different stages. The content of 3-nitrotyrosine (3-NT) and 8-hydroxy-2-deoxyguanosine (8-OH-dG) was measured in the peripheral blood of 134 PD patients at different disease stages (1–4), according to the Hoehn-Yahr functional scale. An increase in the level of 3-NT in blood plasma was observed in all examined patients. In patients at the 2nd, 3rd and 4th stages of the disease, the increase in 3-NT relative to the control was on average 58%, and 30% in patients on the 1st stage, which is significantly different from data obtained at more advanced stages of the disease. Therefore, an increase in the product of oxidative protein metabolism 3-NT in the blood plasma of PD patients is an early PD biomarker, whose expression increases with the progression of the neurodegenerative process. An increase in the level of 8-hydroxy-2-deoxyguanosine relative to the norm was shown in the blood serum of all patients examined. In patients at the 1st, 2nd and 3rd stages of the disease, this increase was on average 60% and, in the most severe cases at the 4th stage of the disease, 183% relative to the control values, which is three times higher than the corresponding values in the other compared subgroups. Thus, the level of 8-hydroxy-2-deoxyguanosine is a biomarker of the most severe disease stages. In this study, we found a systemic increase in the content of both 3-nitrotyrosine and 8-hydroxy-2-deoxyguanosine in blood of patients. The data on the increase in the protein and DNA oxidation products in blood of patients at the first stage of the disease, who had not received any treatment, are of particular importance. The identification of biomarkers of oxidative damage of proteins and nucleic acids at the early stages of PD is an important step towards improving the existing diagnostic criteria, as well as identifying individuals at risk. A significant increase in the content of 8-hydroxy-2-deoxyguanosine in the blood serum of patients at the 4th stage of the disease reflects an association between this index and disease severity and may be important for objective evaluation of disease progression. In general, understanding the pathogenetic factors responsible for the death of dopaminergic neurons, including oxidative damage of lipids, proteins, and nucleic acids, may be of great importance for the development of complex neuroprotective approaches to the treatment of PD and assessment of the effectiveness of treatment.

Abstract—Oxidative stress (OS) plays a significant role in the pathogenesis of Parkinson’s disease (PD) and is accompanied by the development of free radical reactions of lipid peroxidation. The growth of highly reactive products of oxidative metabolism of polyunsaturated fatty acids (PUFAs) leads to dysfunction and the subsequent death of dopaminergic neurons and contributes to the emergence and progression of PD. This paper assesses the prognostic significance of lipid peroxidation (LPO) products determined in the blood of patients with PD as possible biomarkers of various stages of the disease. The content of lipid hydroperoxides (LH), malondialdehyde (MDA), and 4-hydroxynonenals (4-HNE) was determined in the peripheral blood of 240 patients at stages 1–4 of the disease according to the Hoehn and Yahr scale. For all examined patients, regardless of the stage of the disease (stages 2–4), an increase in the level of lipid hydroperoxides by 20% was observed, on average. Elevated levels of MDA were registered in patients with a higher disease severity who were at the advanced stages of the disease (stages 3 and 4). For patients at stages 1 and 2 of the disease the content of MDA remained within normal levels. The content of 4-HNE increased in patients at stages 2, 3, and 4 of the disease proportionally to the severity of the disease. The most pronounced increase in the content of 4-HNE was detected in patients at the advanced stages of the disease (stages 3 and 4). In patients at the second, earlier stage of the disease, the value of this parameter was 34% lower than that in patients at the advanced stages. In patients at the first stage of the disease, all measured parameters of LPO were comparable to control values and therefore could not play a significant diagnostic biomarker role. An important aspect of this study is that some LPO markers (LH and 4-HNE) are associated with both early and late stages of the disease, while the content of MDA increased at the advanced stages. Therefore, MDA and 4-HNE may have a high prognostic value, reflecting the severity of the disease. The most sensitive and specific indicator of LPO is 4-HNE, since its content increases proportionally to the severity of the disease (stage 2 < stage 3 < stage 4). The results we obtained are important for the development of complex neuroprotective approaches to the treatment of this disease, which can prevent the selective death of nervous tissue in PD and delay the development of the neurodegenerative process.

Previously, using in vivo models hystidine containing dipeptide carnosine (β-alanyl-L-hystidine) was shown to inhibit the development of oxidative stress induced by such effects like hypoxia, ischemia and neurotoxin administration. These studies showed that animals having undergone oxidative stress in the settings of carnosine administration preserve habits developed in open field, holeboard and Morris water maze. We investigated the effect of carnosine on cognitive processes in brain in the settings unrelated to the action of damaging factors. Carnosine administration prevented the increase of lipid hydroperoxides levels and increased the antioxidative state of the brain in rats under development of active avoidance response in the shuttle box. In these settings the acceleration of habit development and the increase in ratio of successfully trained animals was reported. At the same time the level of glutamate—the main transmitter amino acid related to the function of brain’s flexibility—in the brain of rats receiving carnosine increased. The results obtained indicate the nootropic properties of carnosine.