Publications by authors named "Lyubomir Vezenkov"

Background: Alzheimer's disease (AD) and Multiple sclerosis (MS) lead to neurodegenerative processes negatively affecting millions of people worldwide. Their treatment is still difficult and practically incomplete. One of the most commonly used drugs against these neurodegenerative diseases is 4-aminopyridine.

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Complex neurological disorders, including Alzheimer's disease, are one of the major therapeutic areas to which multitarget drug discovery strategies have been applied in the last twenty years. Due to the complex multifactorial etiopathogenesis of Alzheimer's disease, it has been proposed that to be successful the pharmaceutical agents should act on multiple targets in order to restore the complex disease network and to provide disease modifying effects. Here we report on the synthesis and the anticholinergic activity profiles of seven multitarget anti-Alzheimer compounds designed by combining galantamine, a well-known acetylcholinesterase inhibitor, with different peptide fragments endowed with inhibitory activity against BACE-1.

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The Alzheimer's disease leads to neurodegenerative processes and affecting negatively million people worldwide. The treatment of the disease is still difficult and incomplete in practice. Galanthamine is one of the most commonly used drugs against the illness.

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Alzheimer's disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive functions decline, is a leading cause for dementia and currently ranked as the sixth foremost cause of death. As of present, treatment of AD is symptomatic without convincing therapeutic benefits and new, effective, therapeutic agents are pursued. Due to massive loss of cholinergic neurons and decreased acetylcholine levels, cholinesterase inhibitors like galantamine, remain the backbone of pharmacological treatment of the disease.

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Background: Inhibitors of acetylcholinesterase (AChE) are used to treat many disorders, among which are neurodegenerative upsets, like Alzheimer's disease (AD). One of the limited licensed AChE inhibitors (AChEIs) used as drugs is the natural compound galantamine (Gal).

Objective: As Gal is a toxic compound, here we expose data about its four derivatives in hybrid peptide-norgalantamine molecules, which have shown 100 times lower toxicity.

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The aim of this study was to assess the effect of newly synthesized derivatives of 4-aminopyridine (4-AP) on cuprizone-induced model of brain demyelination in mice. 4-AP is already approved for the treatment of walking difficulties in patients with multiple sclerosis. The model of demyelination was carried out by the administration of cuprizone to the drinking water of the experimental mice.

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Background: Although no effective treatment for the Alzheimer's disease currently exist, some drugs acting as Acetylcholinesterase inhibitors, like galanthamine have positively affected such patients. β- and/or γ-secretase inhibitors are another type of potential drugs. Here we report synthesis of new peptide-galanthamine derivatives, with expected inhibitory activity against both Acetylcholinesterase and β-secretase.

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New derivatives of galanthamine containing peptide fragments with β-secretase inhibitor activity were synthesized. In position 6 of the galanthamine new shortened analogues of β-secretase inhibitor OM 99-2 (Boc-Val-Asn-Leu-Ala-OH and Boc-Val-Asn-Leu-Ala-Val-OH) were included. The new derivatives of the galanthamine in position 11 including Boc and norgalanthamine in P3 or P4 positions, Val in P2' position and benzylamin in P3'-position were also synthesized.

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Some modified octapeptide analogs of somatostatin with the following structure D-Phe-c(Cys-Phe-D-Trp-Xxx-Yyy-Cys)-Thr-NH2, where Xxx is Lys or Orn and Yyy is Aib (α-aminoisobutyric acid), Ac5c (1-aminocyclopentanecarboxylic acid) or Ac6c (1-aminocyclohexane carboxylic acid) have been synthesized. The peptides were prepared by standard Fmoc-solid phase peptide chemistry method. The direct disulphide bond formation has been employed on the solid phase by Tl(CF3CO2)3.

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New analogues of galanthamine containing peptide fragments either at 6 or 11 position, were synthesized by reaction between galanthamine molecule and dipeptides and tripeptide, derivatives of N-(3,4-dichlorophenyl)-D,L-Ala-OH. The best results according to yields, easily purification of the target products, and simplicity of the scheme realisation was achieved by using of cyanomethyl ester of Boc-Gly-OH as activated compound.

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The sheep skins unhairing process with preliminary alkaline treatment of the wool leads to two unnatural dipeptide mimetics lysinoalanine (Lys(*) - Ala) and ornithinoalanine (Orn(*)- Ala) obtaining. They are result from the keratin hydrolysis process. The changes of wool keratin make it resistant to sulphide degradation.

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During the last years the cases and death due to hemostatic violations exceed that of tumors. Enormous efforts have devoted to the prevention and treatment of some diseases such as arterial thrombosis. Antistasin, a 15 kDa anticoagulant protein isolated from salivary glands of the Mexican leech Haementeria officinalis, has been shown to be a potent inhibitor of Factor Xa in the blood coagulation cascade.

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Intensive investigation connected with the development of new anticoagulant agents for the treatment of cardiovascular diseases was carried out. Direct and specific inhibition of thrombin and Factor Xa-like serine proteases in the coagulation cascade has been the focus of many efforts to design novel anticoagulants over the past decade. This work reports the synthesis and biological activity of new anticoagulant peptide analogues of natural isoforms 2 and 3 of antistasin.

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