Margarita E. Neganova

Novel conjugates of aminoadamantanes with carbazole derivatives as potential multitarget agents for AD treatment

A new group of compounds, promising for the design of original multitarget therapeutic agents for treating neurodegenerative diseases, based on conjugates of aminoadamantane and carbazole derivatives was synthesized and investigated. Compounds of these series were found to interact with a group of targets that play an important role in the development of this type of diseases. First of all, these compounds selectively inhibit butyrylcholinesterase, block NMDA receptors containing NR2B subunits while maintaining the properties of MK-801 binding site blockers, exert microtubules stabilizing properties, and possess the ability to protect nerve cells from death at the calcium overload conditions. The leading compound C-2h has been shown the most promising effects on all analyzed parameters. Thus, these compounds can be regarded as promising candidates for the design of multi-target disease-modifying drugs for treatment of AD and/or similar neuropathologies.

Molecular design of multitarget neuroprotectors 3. Synthesis and bioactivity of tetrahydrocarbazole—aminoadamantane conjugates

A synthetic approach to the design of new multitarget neuroprotectors consisting in combination of the tetrahydrocarbazole and aminoadamantane pharmacophore fragments through a 2-hydroxypropylene spacer upon the reaction of 9-oxiranylmethyl-2,3,4,9-tetrahydro-1H-carbazoles and aminoadamantanes, which affords 1-(adamantan-1-ylamino)-3-(1,2,3,4-tetrahydrocarbazol-9-yl)-propan-2-ols, is proposed. The effect of the synthesized compounds on the neuronal NMDA receptors and the functional characteristics of rat liver mitochondria was studied.

Synthesis and biological evaluation of novel 5-hydroxylaminoisoxazole derivatives as lipoxygenase inhibitors and metabolism enhancing agents

A versatile synthesis of novel 5-hydroxylaminoisoxazoles bearing adamantane moieties has been accomplished using the heterocyclization reactions of readily available unsaturated esters by the treatment with tetranitromethane in the presence of triethylamine and subsequent reduction of resulting 5-nitroisoxazoles by SnCl2 with the participation of THF. A number of obtained isoxazole derivatives were evaluated for their antioxidative activity, inhibition of lipoxygenases and impact on the rat liver mitochondria. The majority of tested compounds demonstrated moderate antiradical activity in DPPH test (up to EC50 16μM). The same compounds strongly inhibited soybean lipoxygenase (up to IC50 0.4μM) and Fe(2+)- and Fe(3+)-induced lipid peroxidation (LP) of rat brain cortex homogenate (up to IC50 0.3μM). All tested isoxazole derivatives promoted the phosphorylating respiratory activity simultaneously with maximal stimulated respiratory activity of mitochondria and do not reveal any toxicity towards the primary culture of rat cortex neurons.

Mitochondrial Permeability Transition Pore as a Suitable Targ e t for Neuroprotective Agents Against Alzheimer’s Disease

BACKGROUND A considerable amount of data suggests the age-related impairments of mitochondrial functions in the development of sporadic forms of neurodegenerative pathologies. Mitochondria and the phenomenon of mitochondrial permeability transition (MPT), which marks the point of no return in cell death cascades, have special value in this regard. It is important that the vulnerability to MPT-inducing factors is increased with aging. Simultaneously, a decrease in the calcium retention capacity of mitochondria is developed, which leads to the disturbance of the functional activity of neurons. METHOD The systematic investigations and web content related to the importance of MPT as the target for the search of neuroprotective and cognitive enhancing drugs, especially with multitargeted action, are reviewed. RESULTS Here, we have highlighted some experimental data that determines the importance of mitochondria for the search of neuroprotective drugs, and drugs with multitargeted action. We have also discussed a number of new compounds with similar properties. Being MPT inhibitors/modulators, virtually all the compounds described in this review have the ability to exhibit a neuroprotective effect, interact with some other targets, providing coupled beneficial therapeutic effects such as cognitive stimulation, anti-seizure, and antidepressant actions. CONCLUSION Inhibitors of MPT, which increases calcium retention capacity of mitochondria, are considered as promising neuroprotective drugs able not only to halt the neurodegenerative cascade, but also to increase the functional activity of neurons.

Neuroprotective Effects of the Securinine-Analogues: Identification of Allomargaritarine as a Lead Compound.

Oxidative stress and mitochondrial disturbances are the common and important causative factors of aging, and play an important role in the late onset of sporadic neurodegenerative diseases, including Alzheimer disease (AD). Furthermore, emerging evidence from in vitro and in vivo disease models suggests that oxidative stress and increased vulnerability to induction of mitochondrial permeability transition leads to the pathogenesis of the neurological disorders. Towards the goals of developing effective neuroprotectors, this article describes the synthesis and neuroprotective studies of various derivatives of the naturally occurring alkaloid securinine, based on which a lead compound, allomargaritarine (a diastereomer of margaritarine), was identified as an effective therapeutic for neuroprotection. Allomargaritarine exhibits high antioxidant activity, and has significant mitoprotective effect on cellular models of neurodegeneration.

Focused design of polypharmacophoric neuroprotective compounds: Conjugates of γ-carbolines with carbazole derivatives and tetrahydrocarbazole

Abstract Alzheimer’s disease has a complex multifactorial nature; therefore, a promising approach for the development of efficient therapeutic agents is the concept of multitarget drugs, which affect several biological targets involved in the pathogenesis of the disease. We developed a synthetic algorithm for conjugating several pharmacophoric ligands acting on the key stages of pathogenesis of several neurodegenerative diseases and synthesized hybrid structures combining the γ-carboline fragment of Dimebon with carbazole and tetrahydrocarbazole moieties. Using the complex primary screening system the structures have been revealed that combine the high inhibitory activity and selectivity towards butyrylcholinesterase with the radical-scavenging activity and the ability to potentiate tubulin polymerization to microtubules with a normal structure and/or prevent mitochondrial permeability transition. The lead compound was identified for future optimization and development of new multi-target drugs against neurodegenerative diseases combining the cognitive-stimulating and neuroprotective potentials.

Investigation of the antioxidant characteristics of a new tryptamine derivative of securinine and its influence on seizure activity in the brain in experimental epilepsy

We studied the mechanisms of the antioxidant activity of a tryptamine derivative of securinine (TDS) and its influence on the dynamics of seizure activity in various models of experimental epilepsy. We found that the new TDS, which possesses an antioxidant and a chelating effect, has anticonvulsant action in lithium-pilocarpine-induced epilepsy and may be of interest as a potential scaffold for the development of new neuroprotective anticonvulsant drugs.

Implications of farnesyltransferase and its inhibitors as a promising strategy for cancer therapy

Ras proteins have been reported to play key role in oncologic diseases. Ras proteins are associated with cellular membranes for its carcinogenic activities through post-translational modifications, including farnesylation. Farnesyltransferase is responsible for a type of Ras membrane targeting, which leads to cancer origin and progression. Inhibitors of farnesyltransferase have been developed as novel anticancer agents. In this review, the role of farnesyltransferase in cancer progression and development has been discussed. Further, the current status of development of farnesyltransferase inhibitors for cancer prevention and treatment has also been reviewed.

1,5-Diaryl-3-oxo-1,4-pentadienes based on (4-oxopiperidin-1-yl)(aryl)methyl phosphonate scaffold: synthesis and antitumor properties

Novel 3,5-bis(arylidene)-4-piperidones modified with diethyl[(aryl)methyl]phosphonate moiety attached to the piperidone nitrogen atom have been synthesized by crotonic condensation of aromatic aldehydes with diethyl[(4-oxopiperidin-1-yl)(aryl)methyl]phosphonates in the presence of LiClO4/Et3N system or acetonitrile solution of boron trifluoride etherate. The synthesized phosphonate derivatives of 3,5-bis(arylidene)-4-piperidone series displayed inhibitory properties toward RD, PC3, HCT116, and MCF7 human cancer cell lines with IC50 values in the range of 2.5–8.5 μM, as assessed by an in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.

N,N’-Substituted Selenoureas as Polyfunctional Antioxidants

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.