Publications by authors named "Kourounakis P"

A series of L-serine amides of antioxidant acids, such as Trolox, ()-3-(3,5-di--butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di--butyl-4-hydroxybenzoic acid (structurally similar to butylated hydroxytoluene), was synthesized. The hydroxy group of serine was esterified with two classical NSAIDs, ibuprofen and ketoprofen. The Trolox derivatives with ibuprofen (7) and ketoprofen (10) were the most potent inhibitors of lipid peroxidation (IC 3.

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Background: Alzheimer's Disease (AD) is one of the most common neurodegenerative disorders, characterized by memory deficits and cognitive impairment. Acetylcholinesterase inhibitors, NMDA receptor antagonists and nootropic agents are used clinically, but they have only symptomatic efficacy, attributed to the multifactorial character of AD. The multi-target directed compound approach is gaining attention and has been under investigation lately.

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Inflammation and oxidative stress are involved in cardiovascular diseases. Nitrogen monoxide participates in the regulation of endothelial processes. Thus, derivatives of classic nonsteroidal anti-inflammatory drugs (NSAIDs), trolox or cinnamic acids esterified with 2-(nitrooxy)ethanol were designed and studied.

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Novel derivatives of some non steroidal anti-inflammatory drugs, as well as of the antioxidants α-lipoic acid, trolox and ()-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid with lorazepam were synthesised by a straightforward method at satisfactory to high yields (40%-93%). All the tested derivatives strongly decreased lipidemic indices in rat plasma after Triton induced hyperlipidaemia. They also reduced acute inflammation and a number of them demonstrated lipoxygenase inhibitory activity.

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Background: The biotransformation of xenobiotics is a homeostatic defensive response of the body against bioactive invaders. Xenobiotic metabolizing enzymes, important for the metabolism, elimination and detoxification of exogenous agents, are found in most tissues and organs and are distinguished into phase I and phase II enzymes, as well as phase III transporters. The cytochrome P450 superfamily of enzymes plays a major role in the biotransformation of most xenobiotics as well as in the metabolism of important endogenous substrates such as steroids and fatty acids.

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Stress can be defined as the homeostatic, nonspecific defensive response of the organism to challenges. It is expressed by morphological, biochemical, and functional changes. In this review, we present biological and oxidative stress, as well as their interrelation.

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Objectives: A series of esters and amides, incorporating an antioxidant residue, such as trolox or caffeic acid, and various moieties with different biological activities, were synthesised. The obtained compounds demonstrated considerable anti-inflammatory, radical scavenging and antioxidant action. Thus, they could reduce carrageenan-induced rat paw oedema by 31-60% at 150 μmol/kg and inhibit rat microsomal membrane lipid peroxidation with IC50 values as low as 1.

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Novel esters of non steroidal anti-inflammatory drugs, α-lipoic acid and indol-3-acetic acid with cinnamyl alcohol were synthesised by a straightforward method and at high yields (60-98%). They reduced acute inflammation more than the parent acids and are potent inhibitors of soybean lipoxygenase. Selected structures decreased plasma lipidemic indices in Triton-induced hyperlipidemia to rats.

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We have designed a number of 2-hydroxy (alkoxy)-2-aryl-4-alkyl-(5,6-alkyl)-morpholines with interesting biological activities, i.e. sympathomimetic, analgesic, drug metabolizing enzyme modulating ability, antioxidant potential, anti-inflammatory and anti-dyslipidemic properties.

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Agents against biologic stress were designed, containing GABA esterified with lorazepam and amidated with (R)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (5) or 3,5-di-tert-butyl-4-hydroxybenzoic acid (6). Compounds 5 and 6 inhibited lipid peroxidation, IC(50) 1.1 and 24 microM.

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A number of newly synthesized 2-[4-(hetero)aromatic]phenyl-2-hydroxy-tetrahydro-1,4-oxazine derivatives were found to inhibit lipid peroxidation (IC50 of the most potent was 20 microM) as well as rat squalene synthase (IC50 for most between 1-10 microM). Antidyslipidemic action was demonstrated in vivo: the most active compound decreased triglycerides, total cholesterol, and LDL-cholesterol of hyperlipidemic rats by 64, 67, and 82%, respectively, at 56 micromol/kg (ip). Most of the novel compounds are more active than the structurally related and reference biphenyl-morpholine, pointing to useful structural approaches for the design of antiatherosclerotic agents.

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EP2302 is a novel nitric oxide donor compound that inhibits squalene synthase. We hypothesized that EP2302 can reduce atherosclerosis in the cholesterol-fed rabbit atherosclerosis model. Animals were fed a high-cholesterol (HC) diet for 4 weeks.

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EP2306 [2-(4-biphenyl)-4-methyl-octahydro-1,4-benzoxazin-2-ol, hydrobromide] inhibits squalene synthase and lipid biosynthesis and possesses antioxidant properties. We hypothesized that EP2306 can effectively modify circulating lipids and reduce atherosclerosis in the cholesterol-fed rabbit. Animals were fed a high-cholesterol diet for 4 weeks followed by 4 (phase 1 and 2) or 12 weeks (phase 3) of drug treatment while on high-cholesterol diet.

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Six novel ibuprofen derivatives and related structures, incorporating a proline moiety and designed for neurodegenerative disorders, are studied. They possess anti-inflammatory properties and three of them inhibited lipoxygenase. One compound was found to inhibit cyclooxygenase (COX)-2 production in spleenocytes from arthritic rats.

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Amine or amide derivatives bearing the 2,6-di-tert-butyl phenol moiety are synthesised. Almost all are antioxidants, reduce acute inflammation and inhibit COX-1 and lipoxygenase activity. The most potent anti-inflammatory, COX-1 inhibitor and antioxidant agent, with low toxicity, is 2,6-di-tert-butyl-4-thiomorpholin-4-ylmethyl-phenol.

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We investigated the effects of EP2306 and EP2302, two novel 2-biphenylmorpholine derivatives, on squalene synthase activity in rabbit and human liver microsomes, lipid biosynthesis, low-density lipoprotein (LDL) receptor expression and LDL protein uptake as well as apoB secretion in HepG2 cells. Both EP2306 and EP2302 inhibited squalene synthase activity dose-dependently. In rabbit liver microsomes, the IC50 values were 33 microM for EP2306 and 0.

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We have designed and synthesized a series of novel molecules having a residue of a classical NSAID and an antioxidant moiety, both attached through amide bonds to a known nootropic structure, an L-proline, trans-4-hydroxy-L-proline or DL-pipecolinic acid residue. The compounds were found to retain anti-inflammatory and antioxidant activities, to acquire hypocholesterolemic action, and to possess a greatly reduced gastrointestinal toxicity. The novel molecules could find useful applications, among others, in slowing the progression or delaying the onset of neurodegenerative diseases.

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The effect on hepatic drug metabolising enzymes was evaluated for three representative structures and that were selected from a series of substituted oxazine derivatives designed to possess particular pharmacological properties such as analgesic, antioxidant and hypolipidemic activity. In addition, since xenobiotic metabolism, reactive oxygen and nitrogen species, atherosclerosis and inflammation are interrelated and mutually affected, the effects of and on acute inflammation in vivo and lipoxygenase activity in vitro were also investigated. It was found that treatment of rats with caused induction of cytochrome P450, enhancement of the metabolism of aminopyrine in vitro and of zoxazolamine and hexobarbital in vivo.

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Tolfenamic acid esters with nitrooxyalcohols are synthesized. They are anti-inflammatory agents reducing carrageenan rat paw edema, with low gastrointestinal and general toxicity. In vitro, they are nitric oxide donors, inhibitors of lipoxygenase and cyclooxygenases.

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Stress is implicated in the pathogenesis of numerous disorders such as cardiovascular diseases or neurodegeneration. The extensive overlap between diseases attributed to stress and oxidative damage is indicative of their potential relationship. We hereby study the influence of alpha-tocopherol (alpha-toc) on the development of stress biomarkers (morphological and biochemical), on specific biomarkers of radical insult (lipid peroxidation, oxidized proteins, or glutathione content in brain and liver), as well as on drug metabolism.

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Novel hybrids of lipoic acid and trolox connected through triamine spacers as well as analogues in which the lipoic acid was attached at different positions of the chroman moiety of vitamin E through an amide bond, were synthesized and exhibited strong inhibition of the microsomal lipid peroxidation. Moreover, the new molecules, at 1 microM concentration, reduced reperfusion arrhythmias and MDA content on isolated rat heart preparations, with the 2- and 5-subtituted chromans possessing the better cardioprotective activity.

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The synthesis and pharmacological evaluation of a series of amide derivatives of NSAIDs with L-cysteine ethyl ester is described. The novel derivatives are potent antiinflammatory, antioxidant and hypocholesterolemic-hypolipidemic agents, while they demonstrate considerably reduced gastrointestinal toxicity. This molecular modification may offer a general route to safer antiinflammatory agents, potentially suitable for chronic use in conditions such as neurodegenerative disorders.

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Liver ischemia followed by reperfusion is an important and common clinical event. A major mechanism is leukocyte adhesion to endothelium followed by release of reactive oxygen metabolites. The aim of this study was to determine the effects of a novel antioxidant ethylenediamine derivative with anti-inflammatory properties (compound IA) on an imitated clinical setting of acute hepatic ischemia-reperfusion injury.

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The influence of four ethanolamine derivatives with anti-inflammatory and antioxidant activity on the in vitro aminopyrine N-demethylation was studied. It was found that these compounds inhibit the N-demethylation of aminopyrine. 1-Cyclohexyl-5-(2-hydroxy-ethylamino)-pentan-2-one (compound 4), possessing the highest inhibitory activity and found earlier to be a potent anti-inflammatory agent, is further tested in vivo on zoxazolamine-induced paralysis, after a single administration to rats, and on aminopyrine N-demethylation, rat hepatic total cytochrome P450 and protein (postmitochondrial and microsomal) content, after a prolonged treatment.

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Three triptycene quinones bearing methoxy groups were prepared following a Diels-Alder methodology and were evaluated for antioxidant and anti-inflammatory activity bearing in mind their structural features that could justify intervention with free radical processes. Improved synthetic pathways were achieved for target molecules 9,10-dihydro-5,8-dimethoxy-9,10-[o]benzenoanthracene-1,4-dione (4), 9,10-dihydro-2-hydroxy-5,8-dimethoxy-9,10-[o]benzenoanthracene-1,4-dione (6), and 9,10-dihydro-2,5,8-trimethoxy-9,10-[o]benzenoanthracene-1,4-dione (9). Under our experimental conditions these compounds showed very significant antioxidant activity offering protection against lipid peroxidation of rat hepatic microsomal fraction while inhibiting the reaction completely at very low concentrations (12.

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