5-lipoxygenase inhibitors with histamine H(1) receptor antagonist activity

Classics in Chemical Neuroscience: Deliriant Antihistaminic Drugs

Antihistaminic drugs are widely used clinically and have long been primarily known for their use to treat severe allergic conditions caused by histamine release. Antihistaminic drugs also exert central nervous system (CNS) effects, acting as anxiolytics, hypnotics, and neuroleptics. However, these drugs also have multiple serious neuropharmacological side-effects, inducing delirium, hyperarousal, disorganized behavior, and hallucinations. Due to their robust CNS effects, antihistamines are also increasingly abused, with occasional overdoses and life-threatening toxicity. Here, we discuss chemical and neuropharmacological aspects of antihistaminic drugs in both human and animal (experimental) models and outline their current societal and mental health importance as neuroactive substances.

[Pathogenetic approach in the treatment of inflammatory diseases of the nose and paranasal sinuses]

In recent years, inflammatory diseases of the nose and paranasal sinuses have been on the rise. In addition to infectious diseases, in the modern world a large percentage of the population suffers from allergic diseases. The approach to therapy and the choice of a drug should take into account the pathogenesis of the inflammatory reaction in the nasal cavity and paranasal sinuses. By exerting its effect, the drug should reduce hyperemia and swelling of the nasal mucosa, reduce the level of mucus secretion, improve the drainage of the paranasal sinuses, i.e. possess vasoconstrictive and anti-allergic properties. As such a drug, you can use the combined intranasal spray Frinozol, which basically contains cetirizine and phenylephrine. The use of Frinozol in the complex treatment of inflammation of the mucous membrane of the nasal cavity and paranasal sinuses contributes to the rapid and pronounced weakening of the symptoms of the disease, and is also the key to successful therapy.

5-Hydroxymethylfurfural (HMF) in Organic Synthesis: A Review of its Recent Applications Towards Fine Chemicals

Background:

5-Hydroxymethylfurfural (5-HMF) is a biomass-derived platform chemical, which can be produced from carbohydrates. In the past decades, 5- HMF has received tremendous attention because of its wide applications in the production of various value-added chemicals, materials and biofuels. The manufacture and the catalytic conversion of 5-HMF to simple industrially-important bulk chemicals have been well reviewed. However, employing 5-HMF as a building block in organic synthesis has never been summarized exclusively, despite the rapid development in this area.

Objective:

The aim of this review is to bring a fresh perspective on the use of 5-HMF in organic synthesis, to the exclusion of already well documented conversion of 5-HMF towards relatively simple molecules such as 2,5-furandicarboxylic acid, 2,5-dimethylfuran and so on notably used as monomers or biofuels.

Conclusion:

As it has been shown throughout this review, 5-HMF has been the object of numerous studies on its use in fine chemical synthesis. Thanks to the presence of different functional groups on this platform chemical, it proved to be an excellent starting material for the preparation of various fine chemicals. The use of this C-6 synthon in novel synthetic routes is appealing, as it allows the incorporation of renewable carbonsources into the final targets.

International Union of Basic and Clinical Pharmacology. XCVIII. Histamine Receptors

Histamine is a developmentally highly conserved autacoid found in most vertebrate tissues. Its physiological functions are mediated by four 7-transmembrane G protein-coupled receptors (H1R, H2R, H3R, H4R) that are all targets of pharmacological intervention. The receptors display molecular heterogeneity and constitutive activity. H1R antagonists are long known antiallergic and sedating drugs, whereas the H2R was identified in the 1970s and led to the development of H2R-antagonists that revolutionized stomach ulcer treatment. The crystal structure of ligand-bound H1R has rendered it possible to design new ligands with novel properties. The H3R is an autoreceptor and heteroreceptor providing negative feedback on histaminergic and inhibition on other neurons. A block of these actions promotes waking. The H4R occurs on immuncompetent cells and the development of anti-inflammatory drugs is anticipated.

(1aR,5aR)1a,3,5,5a-Tetrahydro-1H-2,3-diaza-cyclopropa[a]pentalene-4-carboxylic acid (MK-1903): a potent GPR109a agonist that lowers free fatty acids in humans

G-protein coupled receptor (GPCR) GPR109a is a molecular target for nicotinic acid and is expressed in adipocytes, spleen, and immune cells. Nicotinic acid has long been used for the treatment of dyslipidemia due to its capacity to positively affect serum lipids to a greater extent than other currently marketed drugs. We report a series of tricyclic pyrazole carboxylic acids that are potent and selective agonists of GPR109a. Compound R,R-19a (MK-1903) was advanced through preclinical studies, was well tolerated, and presented no apparent safety concerns. Compound R,R-19a was advanced into a phase 1 clinical trial and produced a robust decrease in plasma free fatty acids. On the basis of these results, R,R-19a was evaluated in a phase 2 study in humans. Because R,R-19a produced only a weak effect on serum lipids as compared with niacin, we conclude that the beneficial effects of niacin are most likely the result of an undefined GPR109a independent pathway.

Therapeutic options for 5-lipoxygenase inhibitors

5-Lipoxygenase (5-LO) catalyzes the conversion of arachidonic acid (AA) into leukotriene (LT) A(4) and 5-hydroperoxyeicosatetraenoic acid. LTA(4) can then be converted into LTB(4) by LTA(4) hydrolase or into LTC(4) by LTC(4) synthase and the LTC(4) synthase isoenzymes MGST2 and MGST3. LTB(4) is a potent chemoattractant for neutrophils, eosinophils and monocytes leading to adherence of phagocytes to vessel walls, neutrophil degranulation and release of superoxide anions. LTC(4) and its metabolite, LTD(4), are potent bronchoconstrictors that increase vascular permeability and stimulate mucus secretion from airways. Recent data also suggest that LT have an immunomodulatory role. Due to these properties, the increased biosynthesis of LT in asthma, and based upon clinical data obtained with CysLT(1) receptor antagonists in asthma patients, there is a consensus that CysLT play a prominent role in asthma. In this review, we summarize the knowledge on possible functions of the 5-LO pathway in various diseases like asthma, cancer and cardiovascular events and review the corresponding potential therapeutic roles of 5-LO inhibitors.

Substituted coumarins as potent 5-lipoxygenase inhibitors

Leukotriene biosynthesis inhibitors have potential as therapeutic agents for asthma and inflammatory diseases. A novel series of substituted coumarin derivatives has been synthesized and the structure-activity relationship was evaluated with respect to their ability to inhibit the formation of leukotrienes via the human 5-lipoxygenase enzyme.

5-Lipoxygenase inhibition by N-hydroxycarbamates in dual-function compounds

A series of N-hydroxycarbamates containing a histaminergic H(1) receptor antagonist pharmacophore was synthesized. In vitro assays determined the compounds had both histaminergic binding and 5-lipoxygenase inhibiting activities comparable to the corresponding N-hydroxyurea analog. Animal models demonstrated antihistaminergic and the 5-lipopxygenase inhibitory activity, with the N-hydroxyurea analog having a better overall profile.

Cetirizine and loratadine-based antihistamines with 5-lipoxygenase inhibitory activity

A series of compounds possessing both H(1) histamine receptor antagonist and 5-lipoxygenase (5-LO) inhibitory activities was synthesized. The H(1)-binding scaffolds of cetirizine, efletirizine, and loratadine were linked to a lipophilic N-hydroxyurea, the 5-LO inhibiting moiety of zileuton. Both activities were observed in vivo, as was increased CYP3A4 inhibition compared to their respective single-function drugs. Selected analogs in the series were shown to be orally active in guinea pig models.