Unusual nanosized associates of carboxy-calix[4]resorcinarene and cetylpyridinium chloride: the macrocycle as a glue for surfactant micelles.

The association of cetylpyridinium chloride (CPC) micelles in the presence of octaacetated tetraphenyleneoxymethylcalix[4]resorcinarene (CR) leads to the formation of unusual spherical supramolecular nanoparticles (SNPs). Within the range of CR/CPC molar ratios from 10/1 to 1/10 (except for 1/8), CR, acting as a counterion, decreases the critical micelle concentration of CPC by one order of magnitude and leads to the formation of SNPs with an average hydrodynamic radius of 164 nm and an average zeta potential of -60 mV. The formation of SNPs was studied by NMR FT-PGSE and 2D NOESY, DLS, TEM, fluorimetry, and UV-Vis methods. The stability of SNPs at different temperatures and pH values and in the presence of electrolytes was investigated. The specificity of the interactions of the SNPs with substrates that were preferentially bound by a macrocycle or CPC micelle was studied. The enhancement of cation dye binding in the presence of SNPs is shown. The presented supramolecular system may serve as a nanocapsule for water-soluble and water-insoluble compounds.

Evaluation of the Hepatoprotective Effect of L-Ascorbate 1-(2-Hydroxyethyl)-4,6-Dimethyl-1,2-Dihydropyrimidine-2-One Upon Exposure to Carbon Tetrachloride.

Hepatoprotective properties of a new pyrimidine derivative - L-ascorbate 1-(2-hydroxyethyl)-4,6-dimethyl-1,2-dihydropyrimidine-2-one, synthesized on the basis Xymedon, were assessed in white rats exposed to CCl4. The compound under study administered prior to exposure to CCl4 reduced the deviation of biochemical parameters from reference values and severity of structural and morphological changes in liver, when compared to the control. Hepatoprotective properties of the studied compound were more pronounced than those of Xymedon.

Amphiphilic calixresorcinarene associates as effective solubilizing agents for hydrophobic organic acids: construction of nano-aggregates.

Here we represent the first example of the formation of mixed nanoscale associates, constructed from amphiphilic calixresorcinarenes and hydrophobic carboxylic acids including drugs. The amidoamino-calixresorcinarene self-associates effectively solubilize hydrophobic carboxylic acids - drugs such as naproxen, ibuprofen, ursodeoxycholic acid and aliphatic dodecanoic acid - with the formation of the mixed aggregates with the macrocycle/substrate stoichiometry from 1/1 to 1/7. The ionization of organic acids and the peripheral nitrogen atoms of the macrocycles with the subsequent inclusion of hydrophobic acids into the macrocycle self-associates is the driving force of solubilization. In some cases, this leads to the co-assembly of the macrocycle polydisperse associates into supramolecular monodisperse nanoparticles with the diameter of about 100 nm. The efficiency of drug loading into the nanoparticles is up to 45% and depends on the structure of organic acid. The dissociation of the mixed aggregates and release of organic acid are attained by decreasing pH.

6-Methyluracil derivatives as acetylcholinesterase inhibitors for treatment of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is the major age-related progressive neurodegenerative disorder. The brain of AD patients suffers from loss of cholinergic neurons and decreased number of synapses [1]. AD is caused by an imbalance between Aß production and clearance, resulting in increased amount of Aß in various forms [2]. Reduction of Aß production and increasing clearance of Aß pathogenic forms are key targets in the development of potential therapeutic agents for AD treatment. Unfortunately, only nosotropic approaches for treatment of AD are currently effective in humans. These approaches mainly focus on the inhibition of brain acetyl-cholinesterase (AChE) to increase lifetime of cerebral acetylcholine [3]. It is important to emphasize that AChE itself promotes the formation of Aß fibrils in vitro and Aß plaques in the cerebral cortex of transgenic mouse models of AD [4]. This property of AChE results from interaction between Aß and the peripheral anionic site of the enzyme (PAS) [5]. Dual binding site inhibitors of both catalytic active site (CAS) and PAS can simultaneously improve cognition and slow down the rate of Aß-induced neural degeneration. Unfortunately, the assortment of AChE PAS ligands is still extremely limited. OBJECTIVE: To study putative advantages of AChE non-charged PAS inhibitors based on 6-methyluracil derivatives for the treatment of Alzheimer's disease. METHODS: In vitro studies. Concentration of drug producing 50% of AChE/BuChE activity inhibition (IC50) was measured using the method of Ellman et al. [6]. Toxicological experiments were performed using IP injection of the different compounds in mice. LD50, dose (in mg/kg) causing lethal effects in 50% of animals was taken as a criterion of toxicity [7]. The ability of compound to block in vitro AChE-induced Aß1-40 aggregation was studied using a thioflavin T (ThT) fluorescent probe [8].In vivo biological assays. For in vivo blood-brain barrier permeation assay brains were removed 30 min after IP injection of LD50 dose of tested compound injection. The inhibitory potency was measured using the method of Ellman.Scopolamine and transgenic models of AD were used to evaluate the influence of compound 35 on spatial memory performance.Water solution of scopolamine was injected to mice (ip) 20 minutes before starting memory test during 14 days [9]. Mice were assigned to 7 groups, including 4 groups receiving injection (ip) of compound in different dosages, donepezil-treated mice (donepezil is conventionally used to treat Alzheimer's disease), positive and negative control groups. Double transgenic (APP/PS1) mice expressing a chimeric mouse/human amyloid precursor protein and a mutant of human presenilin-1 [10] were assigned to 4 groups, including transgenic animals injected (ip) with compound 35 or donepezil solution, positive (transgenes injected with water) and negative (wild-type mice) controls.To evaluate spatial memory performance, mice were trained on a reward alternation task using a conventional T-maze [11]. The criterion for a mouse having learned the rewarded alternation task was 3 consecutive days of at least 5 correct responses out of the 6 free trials.For ß-amyloid peptide load was evaluated quantitatively as a number and summary area of Thioflavine S fluorescent spots in cerebral cortex and hippocampal images using Image J program. Statistical analyses were performed using the Mann-Whitney test. RESULTS: We evaluated the acute toxicity of the most active compounds. The most potent AChE inhibitor compound 35 (IC50 (AChE) = 5 ± 0.5 nM) exhibited the lowest LD50 values (51 mg/kg) and inhibited brain AChE by more than 71 ± 1%. Compound 35 at 10 nM, exhibited a significant (35 ± 9%) inhibitory activity toward human AChE-induced Aß aggregation.Scopolamine injection induced significant decrease in correct choice percentage in T-maze, as well as decrease in percentage of mice reaching criterion for learning the task by day 14. This memory deficit was relieved to some extent either by compound 35 (5 mg/kg) or donepezil (reference compound) treatment (0.75 mg/kg). Interestingly, higher doses of compound 35 (10 and 15 mg/kg) produced less therapeutic effect on spatial memory deficit.Group of APP/PS1 mice showed 3 times lower percentage of reaching behavioral criterion and lower percentage of correct choice in T-maze alternation task comparing to WT mice, whereas compound 35 (5 mg/kg) or Donepezil treatment effectively improved these parameters in APP/PS1 mice.Compound 35 treatment (5 mg/kg) during 14 days significantly reduced percentage of summary area and number of ß-amyloid peptide (ßAP) deposits visualized in sections of cerebral cortex, dentate gyrus, and hippocampal CA3 area in APP/PS1 mice. The most prominent reduction of ßAP load by compound 35 treatment was found in CA3 area and cerebral cortex. Meanwhile, Donepezil treatment (1 mg/kg) during 14 days significantly reduced ßAP load in cerebral cortex but not in dentate gyrus and CA3 area. CONCLUSIONS: Experiments showed that the most potent AChE inhibitor compound 35 (6-methyluracil derivative) permeated the blood-brain barrier, improved working memory in the APP/PS1 transgenic mice and significantly reduced the number and area of Aß plaques in the brain. Thus, compound 35 is a promising candidate as a bi-functional inhibitor of AChE for treatment of AD.

Pirimidine derivatives as hepatoprotective agents.

BACKGROUND: Research and development of effective hepatoprotective medicines is one of the priority areas of research in Russia. Literature data shows that active research and development of hepatoprotectors is carried out both in Russian and other countries [1-6]. Pirimidines are used as hepatoprotective medicines stimulating protein synthesis and reparation of hepatocytes in toxical and infectious liver disorders [7]. In our previous work ee have shown hepatoprotective properties of pyrimidine derivative, named Xymedon [8]. This research, funded by the Russian Science Foundation, is aimed at identifying the most effective hepatoprotectors among pirimidine derivatives. OBJECTIVE: To test hepatoprotective properties of one of the new Xymedon (Xym) derivative - L-ascorbate 1-(2-hydroxyethyl)-4,6-dimethyl-1,2-dihydro-pirimidine-2-one (Asc-Xym) on the toxic liver damage model induce by carbon tetrachloride (CTC, CCl4). METHODS: The toxic liver damage in rats was modeled by subcutaneous injection of CTC (CCl4) in vegetable oil (mixed at 1:1 ratio) at a dose of 2 ml per kg. The experiments were carried out under two schemes: 1) oral administration of Xym or Asc-Xym preparations by gavage at the doses of 10 and 20 mg/kg followed by subcutaneous injection of CTC 1 hour after pyrimidine oral administration and continued for 3-4 days; - this was the design of preventive pyrimidine use, 2) liver damage modeling by CTC subcutaneous injections for 3 days followed by oral administration of Xym, Asc-Xym or Thiotriazolin (Thi) preparations at the doses of 20 mg/kg for 5 days; - this was the design of therapeutic scheme. The rats of control groups were injected with CTC according to the same schemes, but did not get any preparations. We looked at some biochemical parameters of blood serum: alanine aminotran-sferase (AlAT), aspartate aminotransferase (AsAT), their ratio (de Rytis coefficient), and the total protein level as the markers of toxic liver damage. We performed statistical data analysis by rank nonparametric Mann-Whitney U-criterion for comparison of two independent groups. We evaluated pathomorphologic characteristics of liver damage on the histological slices colored with hematoxylin and eosin. RESULTS: Carbon tetrachloride (CTC) caused profound changes in the studied biochemical parameters of rats' blood serum. The AlAT activity level in the serum of control animals in the preventive scheme was 116,23 (the median) with the lower quartile and the upper quartile of 76,96 and 211,71 U/l respectively; the AsAT level was 230,08/201,49-290,03 U/l; this was the increase in comparison with the reference values. De Rytis coefficient was 1,76 /1,47-2,67. This was the decrease in comparison with the reference values of intact group (36,37/28,18-43,3 U/l; 132,95 /118,24-164,00 U/l and 4,26/3,03-5,23 respectively). The differences were statistically significant at P < 0,001. In the experimental groups the changes of the biochemical parameters with respect to the reference values were less marked than in Control. The AlAT level was 89,86/87,06-165,15; 103,23/38,19-270,87 U/l; 80,28/6,12-141,82 and 100,33/62,24-144,64 U/l in the groups of rats treated with Xym at the doses of 10 and 20 mg/kg or Asc-Xym at the doses of 10 and 20 mg/kg respectively. Similarly, in the same groups the AsAT level was 211,19/170,20-250,16; 193,61 /181,57-274,69 U/l; 190,91 /65,21-198,65 and 173,25/135,50-210,70 U/l respectively. The differences of the AsAT level were statistically significant at P < 0,05 in comparison with Control in the both groups treated with Asc-Xym.Nnearly 2 times increase of the AlAT level (67,60/1,22-94,60 U/l) (P = 0,00002) was shown in comparison with the reference values in the rats of Control group in the therapeutic scheme. However the AsAT level (163,80/130,1-178,8 U/l) was only slightly higher than reference values. De Rytis coefficient (2,07/1,78-3,48) was significantly lower than the reference values (P = 0,001). The total protein level (59,36/55,17-60,10 g/l) was lower than the reference values (65,06/62,06-68,98 g/l) by 8,4%. The differences of biochemical parameters as compared with the reference values in rats of experimental groups treated with Xym, Thi and Asc-Xym at the doses 20 mg/kg were less than those in the Control groups. They were: AlAT 52,49/44,64-62,30 and 61,42/53,20-96,66 U/l, AsAT 105,00/94,7-142,3 and 235,35/111,7-335,6 U/l, de Rytis coefficient 2,09/1,87-2,28 and 3,24/1,86-4,53, total protein 63,10/62,46-64,27 and 62,46/58,70-64,43 g/l respectively in the groups treated with Xym and Thi. The values of the studied biochemical parameters AlAT (39,04/32,46-44,24 U/l), AsAT (111,9/105,27-155 U/l), de Rytis coefficient (2,87/2,72-3,30), total protein (62,89/61,46-68,14 g/l) of the rats, treated with Asc-Xym, were the most close to the reference values in comparison with other experimental groups.The analysis of histological slices revealed large areas of steatosis and necrosis of hepatocytes in Control groups in both schemes. These were less pronounced in experimental groups than in Control groups and particularly in rats, treated with Asc-Xym. CONCLUSIONS: Hepatoprtotective properties of the new compound L-ascorbate 1-(2-hydroxyethyl)-4,6-dimethyl-1,2-dihydropirimidine-2-one were established. The hepatoprotective efficacy of the compound is higher than that of Xymedon and Thiotriazolin.

Study of hepatoprotective effects of xymedon.

Xymedon (1-(ß-oxyethyl)-4,6-dimethyl-1,2-dihydro-2-oxopyrimidine), a regeneratory and wound-healing drug, exhibited hepatoprotective activity in laboratory animals with experimental toxic hepatitis. Oral drug reduced the severity of toxic involvement of the liver induced by CCl4 and reduced animal mortality. Xymedon promoted recovery of the blood biochemical parameters characterizing the liver status.

Antianemic activity of water-soluble Na,Ca,Fe-polygalacturonate.

A pronounced antianemic effect of water-soluble Na,Ca,Fe-polygalacturonate is demonstrated. The drug in solution is more effective than in the solid form; it promotes absorption of nutrient calcium and iron. During this treatment, consumed calcium does not impair iron absorption.

[The study of effects of a novel acetylcholinesterase inhibitor on electrical activity of the heart].

We have investigated effect of a representative of the novel class of selective acetylcholinesterase inhibitors A 1,3-bis[5(diethyl-o-nitrobenzyl ammonio) penthyl]-6-methyluracildibromide (compound 547) on duration and rhythm of sequence of right atrial action potential (AP) as well as on kinetics of acetylcholinesterase catalyzed reaction in homogenates of skeletal muscle (m. extensor digitorum longus) and cardiac muscle in the rat. We have shown that contrary to classical acetylcholinesterase inhibitors armin and proserin none of studied concentrations (1, 10 and 100 nM) of compound 547 exerted significant effect on AP configuration and rate of sinus rhythm. Compound 547 belongs to noncompetitive type with K1(heart)=3.6 x 10(-4) M and K1(EDL)=1.3 x 10(-8) M. Proserin exerts comparable inhibitory action on reaction in the heart and skeletal muscle, its K1(heart)=0.73 x 10(-5) M and K1(EDL) = 0.4 x 10(-5) M. Thus low sensitivity of myocardium to compound 547 in electrophysiological experiments is not related to lesser availability of synaptic acetylcholinesterase in the heart compared with acetylcholinesterase in skeletal muscles but reaction catalyzed by cardiac acetylcholinesterase is actually to a substantial degree less prone to inhibition by compound 547.

Effect of pectin substances on contractile activity of the uterine myometrium in rats.

We studied the effects of peptides from Amaranthus cruentus L., Rauwolfia serpentina Benth., and citrus plants on contractile activity of the uterine myometrium in rats. Pectin substances inhibited spontaneous contractile activity of uterine muscles and abolished the stimulatory effect of oxytocin. Pectins had a synergistic effect with epinephrine and acetylcholine.

Different sensitivity of miniature endplate currents of the rat extensor digitorum longus, soleus and diaphragm muscles to a novel acetylcholinesterase inhibitor C-547.

A novel derivative of 6-methyluracil, C-547, increased the amplitude and prolonged the duration of miniature endplate currents (MEPCs) which is typical for acetylcholinesterase inhibition. In the soleus and extensor digitorum longus significant potentiation was detected at nanomolar concentrations. In contrast, in the diaphragm muscle, the increase in the amplitudes of the MEPCs and the decay time constant appeared only when the concentration of C-547 was elevated to 1 x 10(-7) M. Possible consequences for the exploitation of this drug, which can selectively inhibit AChE in particular synapses, are discussed.

Antibacterial and antifungal activity of acyclic and macrocyclic uracil derivatives with quaternized nitrogen atoms in spacers.

The reactions of 1,3-bis(alpha,omega-bromoalkyl)-6-methyluracils with 1,3-bis(alpha,omega-ethylaminoalkyl)-6-methyluracils or 1,3-bis(bromopentyl)thymine with butylamine afforded pyrimidinophanes containing one or two uracil units and nitrogen atoms in bridging polymethylene chains. In some cases individual geometric isomers of pyrimidinophanes differing in the mutual arrangement of the carbonyl and methyl groups at different pyrimidine rings were isolated. Quaternization of the bridging nitrogen atom with o-nitrobenzyl bromide, benzyl bromide, n-decyl bromide gave rise to water-soluble pyrimidinophanes which were evaluated for their antibacterial and antifungal activity. The arrangement of the carbonyl groups in macrocycles doesn't affect the activity. Antibacterial and antifungal activity of pyrimidinophanes increases with the increase of polymethylene N(pyr)-N-chain length and dramatically increases upon the introduction of n-decyl substituent at nitrogen atoms in spacers. Pyrimidinophanes with 5 and 6 methylene groups in N(pyr)-N-chain and n-decyl substituent showed significant bacteriostatic, fungistatic, bactericidal, fungicidal activity which comparable with standard antibacterial and antifungal drugs. Acyclic counterpart demonstrated the highest activity against fungi. Toxicity of more effective pyrimidinophanes was determined for mice and Daphnia magna Straus.

Delayed effects of daphnia intoxication with selective and nonselective inhibitors of acetylcholinesterase.

Chronic experiments on successive generations of laboratory Daphnia magna culture demonstrated higher (compared to proserin) embryotoxicity of a new selective acetylcholinesterase inhibitor 1,3-bis[5-(diethyl-o-nitrobenzilammonio)pentyl]-6-methyluracyl dibromide (compound No. 547). The concentrations of proserin (neostigmine) and compound No. 547 not exceeding 1/60 LC50 (0.39 mol/liter for compound No. 547 and 0.045 mol/liter for proserin) were absolutely safe for the reproductive function of daphnia.

Effect of tetraalkylammonium derivative of 6-methyluracil on amplitude and temporal parameters of miniature endplate potentials in frog neuromuscular junction.

The effect of C-547, a tetraalkylammonium derivative of 6-methyluracil, a novel highly selective acetylcholinesterase inhibitor, on frog neuromuscular junction was studied. In concentrations 10(-9)-10(-7)M the preparation increased the amplitude and temporal parameters of miniature endplate potentials. In contrast to the effect of C-574 on purified acetylcholinesterase from mammals, the effect of this agent on frog neuromuscular junction was reversible. In a concentration of 10(-6)M the preparation apart from anticholinesterase activity produced a parasympatholytic effect manifested in a decrease in amplitude and decay time constant of miniature endplate potentials accompanied by a decrease in spontaneous transmitter secretion. After washout, the parasympatholytic effect recovered more slowly, but disappeared more rapidly compared to anticholinesterase activity. These findings suggest that parasympatholytic effect of C-547 results from direct action on receptor-channel complexes in the endplate membrane.

[Effect of diucifon and its structural precursors on inflammatory and pain reactions]. / Vliianie diutsifona i ego strukturnykh predshestvennikov na vospalitel'nuiu i bolevuiu reaktsii.

The anti-inflammatory and analgesic action of diucifon, methyluracil and 4,4'-diaminodiphenylsulfone (DDS) was studied in comparison with some nonsteroid preparations. In three traditional models of agar, kaolin and carrageenan paw edema and in the models of analgesia (convulsions, induced by intraabdominal administration of acetic acid to mice and hyperalgesia according to Randall-Selitto's test in rats), diucifon proved more active than its precursors. In Randall-Selitto's test the efficiency of diucifon was 1.5 times less than that of butadione but 24 times higher than that of methyluracil; DDS had no analgetic activity. Diucifon, methyluracil and DDS did not exert any ulcerogenic action.