Cancer chemoprevention - selected molecular mechanisms.

The effect of diet on cancer formation and prevention of carcinogenesis has attracted considerable attention for years and is the subject of several studies. Some components of the daily diet, such as resveratrol, curcumin, genistein, gingerol, can significantly reduce the risk of cancer or affect the rate of tumor progression. Cancer chemoprevention assumes the use of natural or synthetic biologically active substances in order to prevent, inhibit or reverse the progression of cancer.

Kynurenic Acid Induces Impairment of Oligodendrocyte Viability: On the Role of Glutamatergic Mechanisms.

Kynurenic acid (KYNA) is an end stage product of tryptophan metabolism with a variety of functions in the human body, both in the central nervous system (CNS) and in other organs. Although its activity in the human brain has been widely studied and effects on neural cells were emphasized, the effect of KYNA on oligodendroglial cells remains unknown. Present study aims at describing the activity of high concentration of KYNA in OLN-93 cells.

Tempol, a Membrane-Permeable Radical Scavenger, Exhibits Anti-Inflammatory and Cardioprotective Effects in the Cerulein-Induced Pancreatitis Rat Model.

To date, it remains unclear whether mild form of acute pancreatitis (AP) may cause myocardial damage which may be asymptomatic for a long time. Pathogenesis of AP-related cardiac injury may be attributed in part to ROS/RNS overproduction. The aim of the present study was to evaluate the oxidative stress changes in both the pancreas and the heart and to estimate the protective effects of 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (tempol) at the early phase of AP.

Quinaldic acid inhibits proliferation of colon cancer ht-29 cells in vitro: effects on signaling pathways.

Quinaldic acid is presumed to be a derivative of kynurenic acid, a tryptophan metabolite with proven antiproliferative activity towards cancer cells in vitro. The aim of present study was to evaluate the activity of quinaldic acid in colon cancer cells. The antiproliferative potential of quinaldic acid was assessed in HT-29, LS180 and Caco-2 cells.

Kynurenic acid inhibits colon cancer proliferation in vitro: effects on signaling pathways.

Kynurenic acid (KYNA), a tryptophan metabolite, inhibits proliferation of several cancer cell lines including colon cancer, renal cancer and glioblastoma cells. Previous studies reported that inhibitory properties of KYNA may be related to interactions of KYNA with cell cycle regulators and signaling proteins. However, the exact molecular interaction of KYNA with signaling pathways in colon cancer cells has not been studied to date.

Kynurenic acid content in anti-rheumatic herbs.

Introduction: The use of herbal medicines is common among people living in rural areas and increasingly popular in urbanized countries. Kynurenic acid (KYNA) is a metabolite of kynurenine possessing anti-inflammatory, anti-oxidative and pain reliving properties. Previous data indicated that the content of KYNA in the synovial fluid of patients with rheumatoid arthritis is lower than in patients with osteoarthritis.

Investigations on the synthesis and pharmacological properties of 4-alkoxy-2-[2-hydroxy-3-(4-aryl-1-piperazinyl)propyl]-6-methyl-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diones.

Synthesis of 2-[2-hydroxy-3-(4-aryl-1-piperazinyl)propyl] derivatives of 4-alkoxy-6-methyl-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diones (8-12) is described. The chlorides used in the above synthesis can exist in two isomeric forms: chain (18-20) and cyclic (19a, 20a). The compounds 8-12 exhibited potent analgesic activity which was superior than that of acetylsalicylic acid in two different tests.

Effect of diazepam and clonazepam on the function of isolated rat platelet and neutrophil.

Background: Benzodiazepine binding sites distinct from the GABA-receptor-chloride-complex in the central nervous system have been recognized in many peripheral tissues, but their physiological role remains unexplained. Our study was undertaken to examine the effects of diazepam, clonazepam, and PK 11195, a peripheral benzodiazepine receptor antagonist, on the functional and biochemical responses of platelets and neutrophils stimulated by different physiological agonists.

Material/methods: The experiments were conducted on isolated washed rat platelets activated by arachidonic acid (AA), adenosine 5'-diphosphate (ADP), or thrombin and on isolated rat neutrophils activated by a chemotactic peptide, formyl methionyl leucyl phenylalanine (fMLP).

Effects of antiepileptic drugs on rat platelet aggregation: ex vivo and in vitro study.

The influence of conventional antiepileptic drugs (valproate, phenobarbital, diazepam, clonazepam, carbamazepine and diphenylhydantoin) on rat platelet activation induced by arachidonic acid (AA) or adenosine-5'-diphosphate (ADP) was investigated both ex vivo and in vitro on platelet-rich plasma (PRP). It was found that only diazepam, and to a smaller extent clonazepam, impaired rat platelet function. These benzodiazepines did not affect ex vivo platelet aggregation induced by ADP but dose-dependent inhibition of platelet aggregation and malondialdehyde (MDA) synthesis were observed, when the platelets were stimulated with AA (ED(50) of diazepam for aggregation was 2.

Synthesis and preliminary screening of derivatives of 2-(4-arylpiperazin-1-ylalkyl)-3-oxoisothiazolo[5,4-b] pyridines as CNS and antimycobacterial agents.

We have synthesized several new isothiazolopyridines possessing a side chain at the isothiazole ring typical, among others, for trazodone or NAN-195. Representatives of the novel isothiazolopyridines were examined for acute toxicity and in several commonly used CNS tests in mice and for arterial blood pressure in rats. Three of the five compounds tested showed significant analgesic activity.

Synthesis of some N-substituted 3,4-pyrroledicarboximides as potential CNS depressive agents.

As a continuation of our work on N-[4-aryl(heteroaryl)piperazin-1-ylalkyl]-3,4-pyrro ledicarboximides, which were characterized by strong analgesic activity and CNS depressive action, several novel N-substituted 3,4-pyrroledicarboximides were prepared and eleven representatives were examined in a series of in vivo CNS tests. A few of these compounds displayed a similar profile of biological selectivity to that of 3,4-pyrroledicarboximides described previously; their structure-activity relationships are discussed.

Investigations on the synthesis and pharmacological properties of amides of 7-methyl-3-phenyl-1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl]-2,4- dioxo-1,2,3,4-tetrahydropyrido[2,3-d]-pyrimidine-5-carboxylic acid.

Synthesis of amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4- tetrahydropyrido[2,3-d]pyrimidine-5-carboxylic acid (6-10) and their 1-[2-hydroxy-3(4-phenyl-1-piperazinyl)propyl] derivatives (11-15) are described. Some of them displayed strong analgesic activity.

Antiplatelets activity of some xanthone derivatives.

The effects of twelve aminoalkanolic derivatives of xanthone on platelet aggregation have been evaluated. Five from them inhibited thrombin-induced platelet aggregation. The most active compound was R-(+)-2-N-(7-chloro-2-xanthonemethyl)-2-N-methylamino-1-butanol [IV] which, at a concentration of 40 micrograms/ml, nearly completely inhibited the aggregation concentration (TAC) of thrombin.

Pharmacological properties of some xanthone derivatives.

A series of aminoalkanolic derivatives of xanthone were examined in some experimental models of epilepsia, i.e., pilocarpine, aminophylline and pentetrazole-induced seizures.

Synthesis and pharmacological screening of some N-(4-substituted-piperazin-1-ylalkyl)-3,4-pyrroledicarboximides.

As an extension of our previous work we describe the synthesis and pharmacological investigation of a new series of derivatives of pyrrole-3,4-dicarboximide possessing the 4-substituted-piperazin-1-ylalkyl group linked to the imide nitrogen. The products were evaluated for acute toxicity, and effectiveness in a series of CNS and arterial blood pressure tests. The preliminary pharmacological screening was determined in animal models.

2-Substituted-3-oxoisothiazolo[5,4-b]pyridines as potential central nervous system and antimycobacterial agents.

The 2-[3-(substituted-amino)-2-hydroxypropyl]-4,6-dimethyl-3-oxo-2,3- dihydroisothiazolo[5,4-b]pyridines 3 were synthesized and pharmacologically evaluated in animal models. The preliminary pharmacological screening study showed that the investigated compounds were toxic and had no significant activity in central nervous system (CNS) tests. Additionally, compounds 3, and several other 2-substituted-4,6- dimethyl-3-oxo-2,3-dihydroisothiazolo[5,4-b]pyridines described here (2), together with those (4) reported in a previous paper, were evaluated in vitro against Mycobacterium tuberculosis H37Rv.

Investigations on the synthesis and properties of N-phenyl derivatives of 1,4-dioxo(1,4,5-trioxo)-1,2,3,4-tetra(1,2,3,4,5,6-hexa) hydropyrido-[3,4-d]pyridazines and allied compounds.

2-(1-Piperidino)- and 2-(4-methyl-1-piperazinyl)-6-methyl-3,4-pyridinedicarboximides (1, 2) react with N-phenylhydrazine yielding N-phenylamino-3,4-pyridinedicarboximides (7, 8). The same reaction with 1,6-dimethyl-2-oxo-1,2-dihydro- and 2-chloro-6-methyl-3,4-pyridinedicarboximides (3, 17) gives the salts of the corresponding N-phenylpyridopyridazines with phenylhydrazine (13, 18), which transform into N-phenylaminoimides (14, 19) during boiling in 80% acetic acid. Compounds 7, 8 and 14 isomerize to the corresponding 2-phenyl-1,4-dioxo(1,4,5-trioxo)-1,2,3,4-tetra(1,2,3,4,5,6-hexa) hydropyrido[3,4-d]pyridazines (9, 10, 15) under the influence of heating in alcoholic solution of C2H5ONa or CH3ONa.

Effect of trans-resveratrol, a natural polyphenolic compound, on human polymorphonuclear leukocyte function.

1. Polymorphonuclear leukocytes (PMN) may contribute to the pathogenesis of acute coronary heart disease (CHD). 2.

Transformation of some pyrido[2,3-d]pyrimidine derivatives into other di- and triheterocyclic systems.

It was stated that three analogous ethyl 2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-5-carboxylates (7-9) react with hydrazine hydrate giving derivatives of the new heterocyclic system pyrido[2,3,4-ef]pyridazino[3,4-e]-1,2,4-triazepine (10-12), pyrido[3,4-d]pyridazine (16-18) and pentaazaphenalene (13-15). The latters were formed in low yields. The results of the preliminary pharmacological study of 2 of these compounds are reported.

Investigations on the synthesis and properties of some N-[4-phenyl(2-pyrimidinyl)-1-piperazinyl]alkyl (hydroxyalkyl)-3,4-pyridinedicarboximides.

Synthesis of 2-substituted N-(4-phenyl-1 piperazinyl)propyl(butyl)- and N-2-hydroxy-3[4-phenyl(2-pyrimidinyl)-1-piperazinyl]propyl-6-methyl-3,4- pyridinedicarboximides [VI-XIV] is described. Some of them displayed depressive action on the central nervous system.

Synthesis and pharmacological evaluation of N-aryl(pyrimidinyl) piperazinylalkyl (hydroxyalkyl) derivatives of 1,2,3,4-tetra- and 1,2,3,4,5,6-hexahydropyrido[3,4-d]pyridazines.

The synthesis of N-aryl(pyrimidinyl)piperazinylalkyl(hydroxyalkyl) derivatives of 1,4-dioxo(1,4,5-trioxo)-1,2,3,4-tetra (and 1,2,3,4,5,6-hexa)hydropyrido[3,4-d]pyridazines is described. Some of them show biological activity in the preliminary pharmacological tests.

Synthesis, chemical and pharmacological properties of some 2,4-dioxo-1,2,3,4,5,6,7,8-octahydropyrimido [4,5-d]pyrimidines.

Synthesis of 6-substituted 2,4-dioxo-1,2,3,4,5,6,7,8-octahydropyrimido[4,5-d]pyrimidines [III-VI] obtained by cyclocondensation of 1-phenyl-6-aminouracil with formaline and the primary amines is described. Compounds III, V, VI in the Mannich reaction with secondary cyclic amines yield the corresponding 3-substituted N-aminomethyl derivatives VII-X. Some of them were active pharmacologically.

Synthesis and biological evaluation of 7-azaanalogues of ipsapirone.

The synthesis and preliminary pharmacological evaluation of 4,6-dimethyl-7-azaipsapirone (5c) and related compounds bearing the r-(phenyl, pyridyl, pyrimidinyl)-1-piperazinyl moiety linked through a butyl or ethoxyethyl chain with the isothiazolo[5,4-b]pyridine system, are described.

Some pharmacological properties and cumulative, subchronic and chronic toxicity of 9-methyl-2-[3-(4-phenyl-1-piperazinylpropyl)] -1,2,3,4-tetrahydro-beta-carbolin-1-one (B-193).

The cumulative, subchronic and chronic toxicity of B-193 were studied on the rats and mice. It was found that this compound exerted weak tendency to cumulation in the body. Only the highest doses of B-193 (70, 40 mg/kg po for 12 weeks) caused the increase of animals mortality.

Investigations on the synthesis and properties of some N-arylpiperazinylalkyl derivatives of 1,4-dioxo (1,4,5-trioxo)-1,2,3,4-tetra (and 1,2,3,4,5,6-hexa)hydropyrido[3,4-d]pyridazines.

2-(1-Piperidino)- and 2-(4-methyl-1-piperazinyl)-6-methyl-3, 4-pyridinedicarboximides (1,2) react with CH3NH-NH2 yielding 3-methyl derivatives of the corresponding 1,4-dioxo-1,2,3,4-tetrahydropyrido[3,4-d] pyridazines (4,5). The same reaction with 1,6-dimethyl-2-oxo-1,2-dihydro-3,4- pyridinedicarboximide (3) affords 2-methyl derivative of the corresponding 1,4,5-trioxo-1,2,3,4,5,6- hexahydropyrido[3,4-d]pyridazine (8. Compounds 4,5 and 8 were transformed into their N-arylpiperazinylalkyl derivatives (13-18) on two ways.