Antioxidant Serine-(NSAID) Hybrids with Anti-Inflammatory and Hypolipidemic Potency.

A series of L-serine amides of antioxidant acids, such as Trolox, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di-tert-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 (IC50 3.4 µΜ and 2.8 µΜ), several times more potent than the reference Trolox (IC50 25 µΜ). Most of the compounds decreased carrageenan-induced rat paw edema (37-67% at 150 µmol/kg). They were moderate inhibitors of soybean lipoxygenase, with the exception of ibuprofen derivative 8 (IC50 13 µΜ). The most active anti-inflammatory compounds exhibited a significant decrease in lipidemic indices in the plasma of Triton-induced hyperlipidemic rats, e.g., the most active compound 9 decreased triglycerides, total cholesterol and low-density lipoprotein cholesterol by 52%, 61% and 70%, respectively, at 150 µmol/kg (i.p.), similar to that of simvastatin, a well-known hypocholesterolemic drug. Since the designed compounds seem to exhibit multiple pharmacological actions, they may be of use for the development of agents against inflammatory and degenerative conditions.

Multi-Target Directed Compounds with Antioxidant and/or Anti- Inflammatory Properties as Potent Agents for Alzheimer's Disease.

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. OBJECTIVE: This review selects several research articles, which describe the design, synthesis and biological evaluation of multi-targeting molecules combining antioxidant or/and anti-inflammatory properties. Compounds with these properties are expected to be beneficial in the treatment of AD. METHODS: This review summarizes the pathobiochemistry of AD as well as the role of oxidative stress and inflammation in the progression of neurodegeneration. It presents novel compounds with antioxidant or/and anti-inflammatory activity that have been tested for their efficacy in neurodegenerative disorders. RESULTS: Various researchers have taken advantage of the multi-targeting drug approach in order to design molecules which may be developed as useful agents for the treatment of neurodegeneration. CONCLUSION: The multi-targeting compound approach is a developing therapeutic strategy for multifactorial diseases, such as AD, and can offer effective agents for their radical treatment.

Design, Synthesis and Study of Nitrogen Monoxide Donors as Potent Hypolipidaemic and Anti-Inflammatory Agents.

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. It was found that the nitrogen monoxide (NO) releasing activity was comparable to that of S-nitroso-N-acetylpenicillamine. The nitrooxy derivatives decreased potently lipid indices in the plasma of hyperlipidaemic rats (30-85%). All compounds presented increased anti-inflammatory activity in vivo, inhibiting carrageenan-induced rat paw oedema as high as 76%, up to six times higher than that of the parent acids. Lipoxygenase inhibitory activity was significant for most of them, although the parent molecules exerted a minor effect (IC50 > 0.2 mM). Those compounds incorporating an antioxidant structure inhibited rat microsomal membrane lipid peroxidation strongly and possessed radical scavenging activity. These results indicated that the described compounds could act at different targets in multifactorial diseases, further limiting the possible adverse effects of drug combinations.

Active Anti-Inflammatory and Hypolipidemic Derivatives of Lorazepam.

Novel derivatives of some non steroidal anti-inflammatory drugs, as well as of the antioxidants α-lipoic acid, trolox and (E)-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. Those compounds acquiring antioxidant moiety were inhibitors of lipid peroxidation and radical scavengers. Therefore, the synthesised compounds may add to the current knowledge about multifunctional agents acting against various disorders implicating inflammation, dyslipidaemia and oxidative stress.

Xenobiotic Metabolising Enzymes: Impact on Pathologic Conditions, Drug Interactions and Drug Design.

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. The activity and the potential toxicity of numerous drugs are strongly influenced by their biotransformation, mainly accomplished by the cytochrome P450 enzymes, one of the most versatile enzyme systems. OBJECTIVE: In this review, considering the importance of drug metabolising enzymes in health and disease, some of our previous research results are presented, which, combined with newer findings, may assist in the elucidation of xenobiotic metabolism and in the development of more efficient drugs. CONCLUSION: Study of drug metabolism is of major importance for the development of drugs and provides insight into the control of human health. This review is an effort towards this direction and may find useful applications in related medical interventions or help in the development of more efficient drugs.

Biologic Stress, Oxidative Stress, and Resistance to Drugs: What Is Hidden Behind.

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. In addition to the mediation in biologic stress (central nervous, immune, and hormonal systems) and oxidative stress, the effect of these phenomena on xenobiotic metabolism and drug response is also examined. It is concluded that stress decreases drug response, a result which seems to be mainly attributed to the induction of hepatic drug metabolizing enzymes. A number of mechanisms are presented. Structure-activity studies are also discussed. Vitamin E, as well as two synthetic novel compounds, seem to reduce both oxidative and biological stress and, consequently, influence drug response and metabolism.

Anti-inflammatory and Hypolipidemic Effect of Novel Conjugates with Trolox and Other Antioxidant Acids.

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 1.4 µM, which is much lower than that of trolox. Most of them could also inhibit soybean lipoxygenase. The thiomorpholine derivatives decreased significantly all lipidemic indices of Triton-induced hyperlipidemia in rats. The most active, the caffeic acid derivative (6), decreases triglycerides, total cholesterol and low density lipoprotein, in the plasma of hyperlipidemic rats, by 70%, 67%, and 73%, respectively, at 150 µmol/kg (i.p.). CONCLUSION: The synthesised compounds, designed to exhibit two or more pharmacological actions, may be considered useful in the study of agents addressed to conditions involving inflammation and oxidative stress.

Esters of some non-steroidal anti-inflammatory drugs with cinnamyl alcohol are potent lipoxygenase inhibitors with enhanced anti-inflammatory activity.

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. Therefore, the synthesised compounds may add to the current knowledge about agents acting against various inflammatory disorders.

Novel compounds designed as antistress agents.

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. Oxidative damage accompanied stress, 5 and 6 reduced radical attack, uropepsinogen, and morphological changes. Stress increased drug metabolism. Treatment with 5 reduced cytochrome P450 and N-demethylation of erythromycin, 35 and 40%. Compounds 5 and 6 decreased lipidemic indices of hyperlipidemic rats 40-63%.

Lipid-lowering (hetero)aromatic tetrahydro-1,4-oxazine derivatives with antioxidant and squalene synthase inhibitory activity.

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.

Antiatherosclerotic properties of EP2302, a novel squalene synthase inhibitor, in the cholesterol-fed rabbit.

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. Animals subsequently received drug or placebo for 4 (n = 15) or 12 weeks (n = 15) while on HC diet. A third group (n = 16) received drug or placebo for 4 weeks while on regular diet (regression group). No significant differences were observed in circulating lipids among any of the treatment groups at each time point during HC intake. The perimeter and area of the ascending aorta covered by lesions were significantly decreased in animals treated with 2 mg/kg EP2302 for 4 weeks (44% and 42% reduction, respectively). Moreover, a significant decrease in the perimeter of the ascending and descending aorta covered by lesions was observed in animals treated with 2 mg/kg EP2302 for 12 weeks (73% and 44% reduction, respectively) as well as in the regression group (61% and 65% reduction, respectively). Treatment with EP2302 did not cause any toxicity in animal vital organs. We have shown that EP2302 inhibits atherosclerosis in the cholesterol-fed rabbit and therefore may serve as a candidate drug to be tested in humans for atherosclerosis-related disorders.

EP2306 [2-(4-biphenyl)-4-methyl-octahydro-1,4-benzoxazin-2-ol, hydrobromide], a novel squalene synthase inhibitor, reduces atherosclerosis in the cholesterol-fed rabbit.

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. In phase 1, the dose-effect relationship of EP2306 on lipids and atherosclerosis was established, and its most effective dose was determined (2 mg/kg). This dose reduced significantly total cholesterol (512 +/- 96 mg/dl before versus 320 +/- 124 mg/dl after treatment, p < 0.05) and atherosclerotic lesions compared with control animals. In phase 2, the effects of 2 mg/kg EP2306, 2.5 mg/kg simvastatin, and their combination were assessed. Although no significant effect on lipid parameters was observed, there was a significant reduction (35 +/- 5%, p < 0.05) of atherosclerotic lesions in animals treated with EP2306, a similar reduction with simvastatin, and a further reduction (48 +/- 7%, p < 0.05) when the two agents were combined. In animals treated for 12 weeks with the drugs (phase 3), only EP2306 significantly reduced atherosclerotic lesions by more than 50%, whereas simvastatin alone or in combination with EP2306 had no effect. Treatment with EP2306 did not adversely affect liver transaminases or cause any histopathological changes on various organs of the animals. In conclusion, we have shown that EP2306 inhibits atherosclerosis in vivo, indicating potential as a novel therapeutic agent for coronary artery disease and other atherosclerosis-related disorders.

Design and study of some novel ibuprofen derivatives with potential nootropic and neuroprotective properties.

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. The HS-containing compounds are potent antioxidants and one of them protected against glutathione loss after cerebral ischemia/reperfusion. They demonstrated lipid-lowering ability and seem to acquire low gastrointestinal toxicity. Acetylcholinesterase inhibitory activity, found in two of these compounds, may be an asset to their actions.

New analogues of butylated hydroxytoluene as anti-inflammatory and antioxidant agents.

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.

Pharmacological characterization in vitro of EP2306 and EP2302, potent inhibitors of squalene synthase and lipid biosynthesis.

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 0.6 microM for EP2302 whereas in human liver microsomes, they were 63 microM for EP2306 and 1 microM for EP2302. Both EP2300 compounds inhibited cholesterol production by HepG2 cells dose dependently with IC50 values of 13.3 microM for EP2306 and 3 microM for EP2302. Furthermore, both EP2300 compounds and simvastatin significantly reduced triglyceride synthesis and apoB secretion and increased LDL receptor expression and LDL uptake in HepG2 cells. In summary, we have shown that EP2300 compounds are potent inhibitors of squalene synthase activity in rabbit and human liver microsomes and also they are effective inhibitors of cholesterol and triglyceride biosynthesis in HepG2 cells. These results suggest that EP2306 and EP2302 might prove to be useful for lipid-lowering and treatment of atherosclerosis in vivo.

Synthesis and pharmacochemical study of novel polyfunctional molecules combining anti-inflammatory, antioxidant, and hypocholesterolemic properties.

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.

Nitric oxide releasing derivatives of tolfenamic acid with anti-inflammatory activity and safe gastrointestinal profile.

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. A two to three carbon chain between carboxylic and nitric ester groups seems optimal for activity.

Stress and active oxygen species--effect of alpha-tocopherol on stress response.

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. In our experimental protocol two groups of female rats are exposed to stress conditions, i.e. cold plus starvation. Before stress and during its application one group is treated with alpha-toc for 20 d (0.42 mmol/kg per os, once daily). Our results indicate that oxidative damage accompanies the development of stress, while treatment with alpha-toc completely prevents stress-induced radical attack and reduces stress indices like plasma corticosterone, uropepsinogen, and morphological changes. It is found that stress increases the drug metabolic potential of the liver (total P450, CYP2E1, or CYP3A1 activity). Administration of alpha-toc, in combination with stress, further increases erythro mycin N-demethylation (CYP3A1) compared to stress control, while 4-nitrophenol hydroxylation (CYP2E1) is not affected significantly.

Synthesis of chroman analogues of lipoic acid and evaluation of their activity against reperfusion arrhythmias.

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.

Synthesis and pharmacological evaluation of amide conjugates of NSAIDs with L-cysteine ethyl ester, combining potent antiinflammatory and antioxidant properties with significantly reduced gastrointestinal toxicity.

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.