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Glaucoma is a widespread neurodegenerative disease for which increased intraocular pressure (IOP) is a primary modifiable risk factor. Recently, we have observed that compounds with oxindole scaffolds are involved in the regulation of intraocular pressure and therefore have potential antiglaucomic activity. In this article, we present an efficient method for obtaining novel 2-oxindole derivatives via microwave-assisted (MW) decarboxylative condensation of substituted isatins with malonic and cyanoacetic acids. Various 3-hydroxy-2-oxindoles were synthesized using MW activation for 5–10 min with high yields (up to 98%). The influence of novel compounds applied in instillations on IOP was studied in vivo on normotensive rabbits. The lead compound was found to reduce the IOP by 5.6 Torr (ΔIOP for the widely used antiglaucomatousic drug timolol 3.5 Torr and for melatonin 2.7 Torr).

The development of multi-target-directed ligands (MTDLs) would provide effective therapy of neurodegenerative diseases (ND) with complex and nonclear pathogenesis. A promising method to create such potential drugs is combining neuroactive pharmacophoric groups acting on different biotargets involved in the pathogenesis of ND. We developed a synthetic algorithm for the conjugation of indole derivatives and methylene blue (MB), which are pharmacophoric ligands that act on the key stages of pathogenesis. We synthesized hybrid structures and performed a comprehensive screening for a specific set of biotargets participating in the pathogenesis of ND (i.e., cholinesterases, NMDA receptor, mitochondria, and microtubules assembly). The results of the screening study enabled us to find two lead compounds (4h and 4i) which effectively inhibited cholinesterases and bound to the AChE PAS, possessed antioxidant activity, and stimulated the assembly of microtubules. One of them (4i) exhibited activity as a ligand for the ifenprodil-specific site of the NMDA receptor. In addition, this lead compound was able to bypass the inhibition of complex I and prevent calcium-induced mitochondrial depolarization, suggesting a neuroprotective property that was confirmed using a cellular calcium overload model of neurodegeneration. Thus, these new MB-cycloalkaneindole conjugates constitute a promising class of compounds for the development of multitarget neuroprotective drugs which simultaneously act on several targets, thereby providing cognitive stimulating, neuroprotective, and disease-modifying effects.

A series of bifunctional Ru(III) complexes with lonidamine-modified ligands (lonidamine is a selective inhibitor of aerobic glycolysis in cancer cells) was described. Redox properties of Ru(III) complexes were characterized by cyclic voltammetry. An easy reduction suggested a perspective for these agents as their whole mechanism of action seems to be based on activation by metal atom reduction. New compounds demonstrated a more pronounced antiproliferative potency than the parental drug; individual new agents were more cytotoxic than cisplatin. Stability studies showed an increase in the stability of complexes along with the linker length. A similar trend was noted for antiproliferative activity, cellular uptake, apoptosis induction, and thioredoxin reductase inhibition. Finally, at concentrations that did not alter water solubility, the selected new complex evoked no acute toxicity in Balb/c mice.

A series of novel organotin(IV) complexes on the base of 2-(N-3′,5′-di-tert-butyl-4′-hydroxyphenyl)-iminomethylphenol (L) of formulae Me2SnBr2(L)2 (1), Bu2SnCl2(L)2(2), Ph2SnCl2(L) (3), Ph2SnCl2(L)2 (4) Ph3SnBr(L)2 (5) were synthesized and characterized by 1H, 13C, 119Sn NMR, IR, ESI-MS and elemental analysis. The crystal structures of initial L and complex 2 were determined by XRD method. It was found that L crystallizes in the orthorhombic syngony. The distorted octahedron geometry around Sn center is observed in the structure of complex 2. Intra- and inter-molecular hydrogen bonds were found in both structures. The antioxidant activity of new complexes as reducing agents, radical scavengers and lipoxygenase inhibitors was estimated spectrophotometrically in CUPRAC and DPPH tests (compounds 1 and 5 were found to be the most active in both methods), and in the process of enzymatic oxidation in vitro of linoleic acid under the action of lipoxygenase LOX 1-B (EC50 > 33.3 μM for complex 2). Furthermore, compounds 1–5 have been investigated for their antiproliferative activity in vitro towards HCT-116, MCF-7 and A-549 and non-malignant WI-38 human cell lines. Complexes 2 and 5 demonstrated the highest activity. The plausible mechanisms of the antiproliferative activity of compounds, including the influence on the polymerization of Tb+MAP, are discussed. Some of the synthesized compounds have also actively induced apoptosis and blocked proliferation in the cell cycle G2/M phase.

The synthesized new binary conjugates of tetrahydro-γ-carbolines, which contained ditriazole spacers of different length, exhibited considerable anticholinesterase and antioxidant activity as well as the potential ability to block the acetylcholinesterase-induced aggregation of β-amyloid in contrast to the original prototype Dimebon. This makes the compounds promising candidates for further investigation as drugs for the treatment of Alzheimer's disease. Special attention should be given to the conjugate containing the hexamethylene intertriazole spacer, which can be considered as a leader in this series of compounds.

Phosphorylation of τ-protein, a component of microtubules in brain neurons, is a key pathomorphological sign of Alzheimer’s disease. The development of this intracellular defect can be promoted by Al3+, Fe3+, and Zn2+ ions. The concentrations of these ions in the brain are considerably elevated in Alzheimer’s disease. We performed a comparative study of phosphorylation of microtubular proteins of rat brain in the presence of Al3+, Fe3+, and Zn2+ ions in concentrations of 10-500 μM and microtubular proteins of brain of patients with Alzheimer’s disease. The most likely candidate for the role of a factor that promotes hyperphosphorylation of τ-protein is Al3+ in concentrations of 250 and 500 μM.

Comparison of the cognition-stimulating effects of Dimebon in a wide dose range revealed a non-monotonic and nontrivial wave-like dose-dependence of its activity. Positive results were obtained at low (0.02-0.05 mg/kg) or high (5-10 mg/kg) doses of Dimebon, while intermediate doses were ineffective. This type of the dose dependence of the pharmacological effect can indicate that the substance has several targets. This fact should be taken into consideration when selecting the doses and concentrations of the substance and its analogues for further studies, and for planning treatment schemes and administration doses in clinical studies.

Compounds that act on mitochondrial functions are considered as promising drugs for the treatment of neurodegenerative diseases and age-related dementias. As a basis for the creation of such potential drugs, bioisosteric cinnamic acid analogs and polymethoxybenzene derivatives were selected. Derivatives of cinnamic acid have a wide range of biological activities, which can be important for drugs aimed at the treatment of neurodegenerative diseases, in particular Alzheimer′s disease. In this work, the neuroprotective activity of bioisosteric cinnamic acid analogs and polymethoxybenzene derivatives was studied. Among the compounds studied, lead substances 3, 4, and 7 have been identified. These compounds show no intrinsic toxicity and have a neuroprotective effect on the cellular model of neurodegeneration associated with calcium stress. The mechanism of their cytoprotective activity is probably due to the influence on mitochondrial functions, because these compounds effectively suppress the calcium-induced process of mitochondrial permeability jump. In addition, one of the substances investigated (7) has antioxidant properties, showing the ability to inhibit lipid peroxidation (LPO) of rat brain homogenate, which may be an additional mechanism of neuroprotective effect. The data obtained make it possible to recommend the investigated substances as a basis for the creation of effective neuroprotective drugs capable of influencing early stages of the development of neurodegenerative diseases., Соединения, направленно действующие на митохондриальные функции, рассматриваются как перспективные лекарственные препараты для лечения нейродегенеративных заболеваний и возрастных деменций. В качестве основы для создания таких потенциальных лекарственных средств были выбраны биоизостерные аналоги коричной кислоты и производные полиметоксибензолов. Производные коричной кислоты имеют широкий спектр биологических активностей, который может иметь значение для лекарственных препаратов, направленных на лечение нейродегенеративных заболеваний, в частности болезни Альцгеймера. В данной работе исследована нейропротекторная активность биоизостерных аналогов коричной кислоты и производных полиметоксибензолов. Среди исследованных соединений выявлены вещества-лидеры 3, 4 и 7. Эти соединения не проявляют собственной токсичности и оказывают нейропротекторный эффект на клеточной модели нейродегенерации, связанной с кальциевым стрессом. Механизм их цитопротекторной активности, возможно, обусловлен влиянием на функции митохондрий, поскольку эти соединения эффективно подавляют кальций-индуцированный процесс скачка митохондриальной проницаемости. Кроме того, одно из исследованных веществ (7) обладает антиоксидантными свойствами, проявляя способность к ингибированию перекисного окисления липидов (ПОЛ) гомогената мозга крыс, что может быть дополнительным механизмом нейропротекторного эффекта. Полученные данные позволяют рекомендовать исследованные вещества в качестве основы для создания эффективных нейропротекторных препаратов, способных повлиять на ранние стадии развития нейродегенеративных заболеваний.

The article provides an overview of our own results of comparative study of influence of ions of iron, zinc and aluminium on the structure of microtubules from tubulin and microtubules associated proteins of rat brain with data on the structure of microtubules from tubulin and microtubules associated proteins from the brain of patients with Alzheimer′s disease (AD). A significant decrease in the amount of soluble tubulin was found in the postmortem brain of AD patients in comparison with the control group in the hippocampus, frontal cortex and substantia nigra, but not in the inferior olive. In vitro polymerization of tubulin and microtubules associated proteins from the brain of AD patients and electron micrographs of microtubules were obtained. The assembly of microtubules from brains of AD patients is disrupted, resulting in defective structures. On the other hand, the study of the influence of Al3+, Fe3+, Zn2+ on the microtubules from rat brains tubulin and microtubules associated proteins assembly and structure has shown that all studied metals are able to reduce the amount of microtubules and induce the assembly of anomal structures. According to the degree of the destructive effect on the microtubules and, accordingly, the possible significance in the pathogenesis of Alzheimer disease, metal ions can be arranged in the following sequence Al3+ > Zn2+ > Fe3+. Moreover, phosphorylation of tubulin and microtubules associated proteins in the presence of aluminum ions to the greatest extent reflects the phosphorylation of these proteins at AD. Comparison of data on the structure of microtubules after their assembly from brains of AD patients tubulin and microtubules associated proteins from brains of AD patients, and from the brain of rats, but in the presence of metal ions, confirm the conclusion about the possible role of the metals in the AD etiopathogenesis., Обобщены собственные результаты сравнительного исследования эффектов ионов железа, цинка и алюминия на структуру микротрубочек в процессе их сборки из тубулина и микротубуллоассоциированных белков мозга крысы с данными по изменению структуры микротрубочек в процессе их сборки из тубулина и белков, ассоциированных с микротрубочками (МАР от англ. microtubules associated proteins), мозга больных болезнью Альцгеймера (БА). В мозге больных БА выявлено значительное снижение количества растворимого тубулина, по сравнению с контрольной группой, в гиппокампе, лобной коре и чёрной субстанции, но не в нижней оливе. Отработаны условия, позволившие впервые провести in vitro полимеризацию тубулина и MAP мозга больных БА и получить электронные микрофотографии образовавшихся структур. Показано, что при БА нарушен процесс сборки микротрубочек, в результате чего образуются дефектные структуры. С другой стороны, исследование влияния ионов Al3+, Fe3+, Zn2+ на сборку и структуру микротрубочек из тубулина и MAP мозга крысы показало, что любой из исследованных нами металлов способен снижать количество микротрубочек и вызывать образование аномальных структур. По степени деформирующего воздействия на микротубулярную систему клеток мозга и, соответственно, возможной значимости в патогенезе БА, ионы металлов можно расположить в следующей последовательности Al3+ > Zn2+ > Fe3+. Более того, спектр фосфорилирования тубулина и MAP в присутствии ионов алюминия в наибольшей степени отражает фосфорилирование этих белков при болезни Альцгеймера. Сопоставление данных о нарушениях структуры микротрубочек, наблюдаемых при их сборке из препаратов тубулина и MAP из мозга больных БА, и из мозга крыс, но в присутствии ионов металлов, подтверждают вывод о возможной роли металлов в этиопатогенезе болезни Альцгеймера.

Antioxidant activity of a pharmaceutical substance hypocard was compared with activity of nitromalic acid and well-known agents nicorandil and Mexidol. The ability of these substances to inhibit spontaneous and oxidant-induced LPO process in rat brain homogenate was analyzed. The mechanisms of these effects were studied. The antioxidant properties of hypocard manifested in the inhibition of Fe(II)-induced LPO were significantly more pronounced in comparison with Mexidol and nicorandil.

The unique physicochemical properties of silver nanoparticles explain their extensive application in consumer goods, food, and medicinal products. However, the biological effects of nanosilver after peroral exposure of mammals are still debatable. This study describes the biodistribution and biological action of 12nm non-coated silver nanoparticles intragastrically administered to male rats after acute (single exposure) and sub-acute (multiple exposures over 30 days) toxicity experiments. The daily doses were 2000 and 250mg/kg of body weight for single and multiple administrations, respectively. Silver tissue detection was conducted by elemental analysis with the help of atomic absorption spectroscopy. An estimation of the state of exposed animals was made and the dynamics of hematological and biochemical parameters of rats was studied. It was demonstrated that single and multiple administrations resulted in silver accumulation in the liver, kidneys, spleen, stomach, and small intestine. After both one- and repeated-dose exposures, the highest Ag contents were detected in the liver (0.87±0.37μg/g of organ) and kidneys (0.24±0.02μg/g of organ). The concentrations of silver detected in tissues were far smaller than the administered doses (

Dimebon (Dimebolin) is an antihistamine drug which has been used in Russia since 1983. Recently Dimebolin has attracted renewed interest after being shown to have positive effects on persons suffering from Alzheimer's disease. Animal studies have shown that dimebon acts through multiple mechanisms, both blocking the action of neurotoxic beta-amyloid peptides and inhibiting L-type calcium channels, modulating the action of AMPA and NMDA glutamate receptors. Our experiments with cell culture L929 and mice have shown that dimebon may exert its neuroprotective effect by blocking cytotoxic signals induced by proinflammatory cytokines such as TNF-a which are believed to play a central role in Alzheimer's disease. Dimebon (10 mg/ml) protected mouse fibroblasts L929 against the toxic action of TNF-a. Our study included 65 male mice. TNF-a (10 mg per mouse), dimebon (0,2 mg/kg) and their combination were injected intraperitonealy. Changes in the level of molecular species of sphingomyelin and galactosyl ceramide in hippocampus, cerebellum and cerebral cortex within 30 min, 2 h, 4 h, and 24 h after injection were detected by chromato-mass-spectrometry. Maximal changes in sphingomyelin and galactosyl ceramides contents of different molecular species after single TNF-a administration were found in the hippocampus, and were less expressed in the cerebral cortex and cerebellum after 24 h. Dimebon itself did not induce changes in the sphingolipid spectrum in brain sections, but protected them against disorders induced by TNF-a in the brain. Modern strategies in the search of new therapeutic approaches are based on the multitarget properties of new drugs. According to our results TNF-a may serve as a new target for dimebon.Dimebon, nachinaia s 1983 g., ispol'zuetsia v Rossii v kachestve antigistaminnogo sredstva. Povtornoe vozniknovenie interesa k dimebonu obuslovleno obnaruzheniem ego lechebnogo éffekta pri bolezni Al'tsgeĭmera. Issledovaniia, provedennye na zhivotnykh, pokazali, chto aktivnost' dimebona opredeliaetsia mnozhestvom mekhanizmov. Na kletochnoĭ linii L929 fibroblastov myshi i myshakh S57Bl nami pokazano, chto dimebon sposoben blokirovat' toksicheskie signaly, indutsirovannye provospalitel'nym tsitokinom – faktorom nekroza opukholeĭ-al'fa (FNO-a). V doze 10 mkg/ml dimebon zashchishchaet kletki L929 ot toksicheskogo deĭstviia FNO-a. Predvaritel'noe vvedenie dimebona mysham preduprezhdalo izmeneniia molekuliarnykh vidov sfingomielinov (SM) i galaktoziltseramidov, vyzvannye odnokratnoĭ in"ektsieĭ FNO-a. Pri étom sam dimebon ne vyzyval izmeneniĭ v sfingolipidakh issledovannykh struktur mozga.

In in vitro experiments, amiridine in concentration of 100, 200, and 300 microM restored disturbed structure of microtubules assembled from tubulin and microtubule-associated proteins isolated from the brain of patients with Alzheimer disease. Tacrine in a concentration of 100, 250, and 500 microM inhibited phosphorylation of tubulin and microtubule-associated proteins isolated from the brain of patients with Alzheimer disease, while memantine and amiridine in the specified concentrations had no effect on phosphorylation.

Iron-chelating activity of synthesized spirocyclic hydroxamic acids, their toxicity, and effects on mitochondrial function were studied using primary culture of cerebral cortical neurons from newborn rats. All tested compounds effectively chelated Fe(II) ions. Activity of spirocyclic hydroxamic acids more strictly depended on the structure their piperidine, but not imidazolidine fragment. All compounds were non-toxic for normal neuronal culture.

Al(3+), Fe(3+), and Zn(2+) ions can disturb microtubule assembly from tubulin and microtubuleassociated proteins in rat brain. The main structural forms of these microtubules are rings and tangled bundles. These structures are formed only in the presence of Al(3+) and Fe(3+) ions. Therefore, Zn(2+) ions can be excluded from possible causes of structural abnormalities in microtubules during Alzheimer's disease. Al(3+) ions are the most probable etiological cause of Alzheimer's disease. The concentration of Al(3+) ions affecting the structure of microtubules is one order of magnitude lower than that of Fe(3+) ions (10 and 100 μM, respectively), which corresponds to their brain concentration reported in Alzheimer's disease.

It is shown for the first time that microtubular proteins isolated from the brain of patients with Alzheimer's disease can in vitro polymerize into microtubules with abnormal structure.

The review and summarizes own and literature data about the role of mitochondria as the important target in the search for drugs for the treatment of neurodegenerative diseases. Aging is a major risk factor for sporadic forms of various neurodegenerative diseases, including Alzheimer′s disease. One of the most argued and currently accepted theories is the Mitochondrial Free Radical Theory of Aging. Mitochondrial hypotheses of the development of sporadic forms of neurodegenerative diseases particularly Alzheimer′s disease, are closely connected with it. Impairments of mitochondrial functions lead to a decrease in their ability to regulate calcium homeostasis in the cell and to a decrease in the threshold for the induction of mitochondrial permeability transition (MPT) pores. MPT inhibitors can be considered as a promising approach to the treatment of neurodegenerative diseases, since these drugs can not only exhibit the properties of neuroprotectors, but also can provide normalization of synaptic activity due to increased calcium capacity of mitochondria. The review presents data on the number of MPT inhibitors, including endogenous compounds melatonin and N-acetylserotonin, their bioisosteric analogue Dimebon and a number of other compounds. The use of mitochondria as a basis for the formation of screening strategy for the search for compounds for the treatment of neurodegenerative diseases is of particular interest – both as a test of their potential toxicity, and as a basis for the creation of metabolic stimulants and drugs with neuroprotective and cognitive-stimulating effect., Обобщены собственные и литературные данные, обосновывающие роль митохондрий как важнейшей мишени при поиске препаратов для лечения нейродегенеративных заболеваний. Старение является основным фактором риска спорадических форм различных нейродегенеративных заболеваний, в том числе и болезни Альцгеймера (БА). Одной из наиболее аргументированных и принятых в настоящее время является свободнорадикальная митохондриальная теория старения. Именно с ней тесно связаны и митохондриальные гипотезы развития спорадических форм нейродегенеративных заболеваний и, в частности, БА. Нарушение митохондриальных функций приводит к снижению их способности регулировать гомеостаз кальция в клетке и снижению порога для индукции поры митохондриальной проницаемости (МРТ). Ингибиторы МРТ можно рассматривать как перспективный подход к терапии нейродегенеративных заболеваний, так как эти препараты могут не только проявлять свойства нейропротекторов, но и обеспечивать нормализацию синаптической активности благодаря увеличенной кальциевой ёмкости митохондрий. В обзоре представлены данные о ряде ингибиторов МРТ, включая эндогенные соединения – мелатонин, N-ацетилсеротонин, их биоизостерный аналог димебон и ряд других соединений. Использование митохондрий как основы для формирования скрининговой стратегии поиска соединений для лечения нейродегенеративных заболеваний представляет особый интерес и как тестирование их потенциальной токсичности, и как основа для создания метаболических стимуляторов и препаратов, обладающих нейропротекторным и когнитивно-стимулирующим действием.

We performed screening of potential antioxidants among natural lactone and alkaloid derivatives and characterized their antioxidant effects. The substances exhibiting antioxidant and metal-chelating potential, in particular, tryptamine derivatives, are promising neuroprotector agents.

Analysis of antioxidant activity of synthesized selenourea derivatives showed that N,N'-substituted selenoureas inhibited Fe(III)-induced LPO in rat brain homogenate. On the other hand, oxygen- and sulfur-containing analogs exhibited no antioxidant activity or even slight prooxidant activity. Intramolecular alkylation of selenium atom also led to loss of antioxidant activity. Thus, antioxidant activity of the compounds was due to the presence of a nonalkylated selenium atom in N,N'-substituted selenourea analogs.

New bicyclic derivatives (IV) and (VI) can neither scavenge radicals nor affect the peroxide oxidation of lipids in rat brain homogenates.

We studied the effects of anti-Alzheimer drugs (tacrine, amiridine, and memantine) on phosphorylation of tubulin and microtubule-associated proteins isolated from rat brain, evaluated the capacity of these proteins to polymerize into microtubules after addition of study pharmacological agents, and analyzed the structure of generated microtubules. It was shown that test substances impair assembly of microtubules to a different extent. Dose-dependent effects of these agents on phosphorylation of tubulin and microtubule-associated proteins were observed. Triazolam (not approved for clinical use as anti-Alzheimer drug) in the same concentrations was used as the reference substance in the same tests. It was observed that this substance even in minimal concentration induced the most pronounced changes in microtubule structure. A direct correlation between the capacity of the test substances to modulate tubulin phosphorylation and to impair microtubule structure was found: the more the substance inhibited tubulin phosphorylation, the more it disordered microtubule structure.

Dimebon, a Russian-made drug, inhibited toxic effects of beta -amyloid on cultured neurons. Excessive accumulation of beta-amyloid in the brain is characteristic of Alzheimer dementias. Antialzheimer preparations tacrine and dimebon improve survival of cerebellar granule cells during long-term incubation with Ab25-35, the neurotoxic fragment of beta-amyloid. Both preparations can block potential-dependent Ca2+ entry into neurons by about 20%, which is explained by their selective action on L-type Ca2+ channels. It was assumed that the neuroprotective effect of dimebon and tacrine against Ab25-35 partially depends on inhibition of potential-dependent Ca2+ entry.