Inhibition of the enzymes in the leukotriene and prostaglandin pathways in inflammation by 3-aryl isocoumarins

Protective effects of licofelone on scopolamine-induced spatial learning and memory impairment by enhancing parkin-dependent mitophagy and promotion of neural regeneration and in adult mice

Inhibition of COX and LOX could contribute to memory formation and prevention of neurodegeneration, by alleviation of neuroinflammation and improvement of mitochondrial homeostasis. We aimed to assess the effect of licofelone, a dual COX and 5-LOX inhibitor on memory formation, neural apoptosis, neural regeneration, and mitophagy in acute and chronic dosages, given that licofelone could regulate nitric oxide levels. Y-maze and Passive Avoidance tests were used to evaluate memory function in NMRI mice using the EthoVision setting, following scopolamine administration (1 mg/kg, i.p.) as an acute amnestic drug. Hippocampi were used to evaluate the levels of apoptosis via TUNEL assay, neural regeneration via immunohistochemistry method detecting doublecortin and nestin, and mitophagy via Western blot of mitophagy proteins Parkin and ATG5. While acute high-dose licofelone (20 mg/kg) could reverse amnestic effects of scopolamine in passive avoidance test (p = 0.0001), Chronic licofelone (10 mg/kg for 10 consecutive days) could improve performance in Y-maze (p = 0.0007). Molecular analysis revealed that the chronic form of the drug could enhance neural regeneration in CA1 and SGZ regions, reset mitophagy levels as much as the healthy state, and reduce apoptosis rate. Licofelone appears to show a desirable anti-amnestic profile in a low dose chronically; it is hence recommended for future clinical studies on the prevention of neuroinflammation and memory deficit.

Anti-Inflammatory Effects of the Combined Treatment of Resveratrol- and Protopanaxadiol-Enriched Rice Seed Extract on Lipopolysaccharide-Stimulated RAW264.7 Cells

The overproduction of proinflammatory cytokines triggers a variety of diseases. Protopanaxadiol (PPD) and resveratrol are naturally found in plants such as ginseng and have potential anti-inflammatory properties, and resveratrol- and PPD-enriched rice seeds have been previously successfully generated. Herein, the synergistic anti-inflammatory activities of extracts of these enriched seeds were assessed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In comparison with treatment using extract prepared from PPD-producing transgenic rice (DJ-PPD) alone, cotreatment with DJ526 and DJ-PPD (TR_3) markedly enhanced the anti-inflammatory activities at a similar (compared to DJ526) or higher (compared to DJ-PPD) level. Cotreatment with DJ526 and DJ-PPD markedly inhibited the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Thus, DJ526 and DJ-PPD in combination suppressed the expression of phosphorylated (p)-NF-κB p65, p-p38 MAPK, and p-ERK 1/2. Cotreatment with DJ526 and DJ-PPD downregulated the expression of proinflammatory cytokines (IL-1β, IL-6, and TNF-α), LPS receptor (toll-like receptor-4, TLR-4), proinflammatory mediators (nitric oxide and PGE2), and arachidonic acid pathway critical enzyme (COX-2). These findings demonstrate the synergistic potential anti-inflammatory activities of resveratrol- and PPD-enriched rice seed extract.

Salsoline derivatives, genistein, semisynthetic derivative of kojic acid, and naringenin as inhibitors of A42R profilin-like protein of monkeypox virus: in silico studies

Monkeypox virus (MPV) infection has developed into a re-emerging disease, and despite the potential of tecovirimat and cidofovir drugs, there is currently no conclusive treatment. The treatment's effectiveness and cost challenges motivate us to use In Silico approaches to seek natural compounds as candidate antiviral inhibitors. Using Maestro 11.5 in Schrodinger suite 2018, available natural molecules with validated chemical structures collected from Eximed Laboratory were subjected to molecular docking and ADMET analysis against the highly conserved A42R Profilin-like Protein of Monkeypox Virus Zaire-96-I-16 (PDB: 4QWO) with resolution of 1.52 Å solved 3D structure. Compared to the FDA-approved Tecovirimat, molecular docking revealed that Salsoline derivatives, Genistein, Semisynthetic derivative of kojic acid, and Naringenin had strengthened affinity (-8.9 to -10 kcal/mol) to 4QWO, and the molecular dynamic's simulation confirmed their high binding stability. In support of these results, the hydrogen bond analysis indicated that the Salsoline derivative had the most robust interaction with the binding pockets of 4QWO among the four molecules. Moreover, the comparative free energy analyses using MM-PBSA revealed an average binding free energy of the complexes of Salsoline derivative, Genistein, Semisynthetic derivative of kojic acid, Naringenin, of -106.418, -46.808, -50.770, and -63.319 kJ/mol, respectively which are lower than -33.855 kJ/mol of the Tecovirimat complex. Interestingly, these results and the ADMET predictions suggest that the four compounds are promising inhibitors of 4QWO, which agrees with previous results showing their antiviral activities against other viruses.

Recent Advances in the Synthesis of Diarylheptanoids

In the quest for synthesizing biologically important natural products, medicinal chemists embark on an endless journey. This review focuses on the reports published towards the syntheses of diarylheptanoids, classifying them into linear, tetrahydropyran, diarylether, and biphenyl categories. The synthesis methods for each class from 2013 to 2023 are discussed, providing a comprehensive overview of the advancements in the field. Representative natural product examples are highlighted for each category. The review emphasizes the importance of diarylheptanoids in the realms of chemistry and medicine, showcasing their potential as valuable compounds for medicinal and synthetic chemists.

Treatment of allergy: Overview of synthetic anti-allergy small molecules in medicinal chemistry

The prevalence of allergic diseases has been continuously increasing over the past few decades, affecting approximately 20-30% of the global population. Allergic reactions to infection of respiratory tract, digestive tract, and skin system involve multiple different targets. The main difficulty of anti-allergy research is how to develop drugs with good curative effect and less side effects by adopting new multi-targets and mechanisms according to the clinical characteristics of different allergic populations and different allergens. This review focuses on information concerning potential therapeutic targets as well as the synthetic anti-allergy small molecules with respect to their medicinal chemistry. The structure-activity relationship and the mechanism of compound-target interaction were highlighted with perspective to histamine-1/4 receptor antagonists, leukotriene biosynthesis, Th2 cytokines inhibitors, and calcium channel blockers. We hope that the study of chemical scaffold modification and optimization for different lead compounds summarized in this review not only lays the foundation for improvement of success rate and efficiency of virtual screening of antiallergic drugs, but also can provide valuable reference for the drug design of related promising research such as allergy, inflammation, and cancer.

Organocatalytic enantioselective construction of axially chiral (1H)-isochromen-1-imines

Heterocycloalkenyl atropisomers, derived from biaryl atropisomers and axially chiral styrenes, have emerged as a new class of nonbiaryl C-C atropisomers due to the benefit in improving the pharmacological activity and structural diversity. This paper proposes an intramolecular annulation strategy for constructing the heterocycloalkenyl atropisomers (1H)-isochromen-1-imines by organocatalysis. Various heterocycloalkenyl atropisomers (1H)-isochromen-1-imines were prepared in good to excellent yields with excellent enantioselectivity (up to 98% ee), and could be easily converted to atropisomeric lactones isocoumarins.

Discovery of Natural Product Inspired 3-Phenyl-1H-isochromen-1-ones as Highly Potent Antioxidant and Antiplatelet Agents: Design, Synthesis, Biological Evaluation, SAR and in silico Studies

BACKGROUND

Several natural/synthetic molecules having structure similar to 1H-isochromen-1-ones have been reported to display promising antioxidants and platelet aggregation inhibitory activity. Isocoumarin (1H-2-benzopyran-1-one) skeleton, either whole or as a part of molecular framework, have been explored for their antioxidant or antiplatelet activities.

INTRODUCTION

Based on literature, a new prototype i.e., 3-phenyl-1H-isochromen-1-ones based compounds have been rationalized to possess both antioxidant as well as antiplatelet activities. Consequently, no reports are available regarding its inhibition either by cyclooxygenase-1 (COX-1) enzyme or by arachidonic acid (AA)-induced platelet aggregation. This prompted us to investigate 3-phenyl-1H-isochromen-1-ones towards antioxidant and antiplatelet agents.

METHODS

The goal of this work to identify new 3-phenyl-1H-isochromen-1-ones based compounds via synthesis of a series of analogues and performing in vitro antioxidant as well as AA-induced antiplatelet activities and then, identification of potent compounds by SAR and molecular docking studies.

RESULTS

Out of all synthesized 3-phenyl-1H-isochromen-1-ones analogues, five compounds showed 7-folds to 16-folds highly potent antioxidant activities than ascorbic acid. Altogether, ten 3-phenyl-1H-isochromen-1-one analogues displayed antioxidant activities in 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Almost, all the 3-phenyl-1H-isochromen-1-one analogues exhibited potent AA-induced antiplatelet activity; few of them displayed 7-folds more activity as compared to aspirin. Further, in silico analysis validated the wet results.

CONCLUSION

We disclose the first detailed study for the identification of 3-phenyl-1H-isochromen-1-one analogues as highly potent antioxidant as well as antiplatelet agents. The article describes the scaffold designing, synthesis, bioevaluation, structure-activity relationship and in silico studies of pharmaceutically privileged bioactive 3-phenyl-1H-isochromen-1-one class of heterocycles.

Natural Products & Bioactivity Inspired Synthetic Pursuits Interfacing with Carbohydrates: Ongoing Journey with C-Glycosides

Natural products, remains the most important source for the discovery of new drugs for the treatment of human diseases. This has inspired the synthetic community to design and develop mimics of natural products either to answer important questions in biology or to explore their therapeutic potentials. Glycosides present themselves abundantly in nature, right from the cell surface receptors to natural products of any origin. The O-Glycosides are hydrolytically less stable compared to C-glycosides and this feature has presented a great opportunity for drug discovery. The discovery of Dapagliflozin, an SGLT inhibitor and C-glucoside, for the treatment of diabetes is one such example. Aryl acyl-anion chemistry has been explored for the synthesis of 2-deoxy-C-aryl furanoside/pyranoside/septanosides. Besides success, the studies have provided valuable insight into the natural propensities of the architectural framework for the cascade to furan derivatives. The aryl acyl-anion chemistry has also enabled the synthesis of biologically active diaryl heptanoids. Inspired from sucesss of Dapagliflozin, new analogues have been synthesized with pyridine and isocoumarin heterocycle as the proximal ring. C-glucosides of isoliquiritigenin have been synthesized for the first time and evaluated as an efficient aldose reductase inhibitor. The synthesis and evaluation of acyl-C-β-D-glucosides and benzyl-C-β-D-glucoside as glucose-uptake promoters has revealed promise in small molecules. The concept of building blocks has been used to obtain natural oxylipins, D-xylo and L-xylo-configured alkane tetrols and novel lipophilic ketones with erythro/threo configured trihydroxy polar head-group as possible anti-mycobacterial agents.

PdCl2-catalyzed synthesis of a new class of isocoumarin derivatives containing aminosulfonyl / aminocarboxamide moiety: First identification of a isocoumarin based PDE4 inhibitor

While anti-inflammatory properties of isocoumarins are known their PDE4 inhibitory potential was not explored previously. In our effort the non-PDE4 inhibitor isocoumarins were transformed into the promising inhibitors via introducing an aminosulfonyl/aminocarboxamide moiety to the C-3 benzene ring attached to the isocoumarin framework. This new class of isocoumarins were synthesized via a PdCl2-catalyzed construction of the 4-allyl substituted 3-aryl isocoumarin ring starting from the appropriate 2-alkynyl benzamide derivative. Several compounds showed good inhibition of PDE4B in vitro and the SAR indicated superiority of aminosulfonamide moiety over aminocarboxamide in terms of PDE4B inhibition. Two compounds 3q and 3u with PDE4B IC50 = 0.43 ± 0.11 and 0.54 ± 0.19 μM and ≥ 2-fold selectivity over PDE4D emerged as initial hits. The participation of aminosulfonamide moiety in PDE4B inhibition and the reason for selectivity though moderate shown by 3q and 3u was revealed by the in silico docking studies. In view of potential usefulness of moderately selective PDE4B inhibitors the compound 3u (that showed PDE4 selectivity over other PDEs) was further evaluated in adjuvant induced arthritic rats. At an intraperitoneal dose of 30 mg/kg the compound showed a significant reduction in paw swelling (in a dose dependent manner), inflammation and pannus formation (in the knee joints) as well as pro-inflammatory gene expression/mRNA levels and increase in body weight. Moreover, besides its TNF-α inhibition and no significant toxicity in an MTT assay the compound did not show any adverse effects in a thorough toxicity studies e.g. teratogenicity, hepatotoxicity, cardiotoxicity and apoptosis in zebrafish. Thus, the isocoumarin 3u emerged as a new, safe and moderately selective PDE4B inhibitor could be useful for inflammatory diseases possibly including COVID-19.

Continuous Electrochemical Synthesis of Iso-Coumarin Derivatives from o-(1-Alkynyl) Benzoates under Metal- and Oxidant-Free

A non-oxidant and metal-free strategy for synthesizing iso-coumarin by using a continuous electrochemical microreactor to initiate an oxidative cyclization reaction of o-(1-alkynyl) benzoate and radicals. This efficient and clean continuous electrosynthesis method not only avoids the complicated gas protection operation and production of by-products in the batch processes, but also help to overcome the difficulty that batch metal catalysis and electrocatalysis are difficult to scale up, and has the potential for pilot-scale experiment.

5-Lipoxygenase as a drug target: A review on trends in inhibitors structural design, SAR and mechanism based approach

The most common inflammatory disease of the airways is asthma among children affecting around 235 million people worldwide. 5-Lipoxygenase (5-LOX) is a crucial enzyme which helps in the conversion of arachidonic acid (AA) to leukotrienes (LTs), the lipid mediators. It is associated with several inflammation related disorders such as asthma, allergy, and atherosclerosis. Therefore, it is considered as a promising target against inflammation and asthma. Currently, the only drug against 5-LOX which is available is Zileuton, while a few inhibitors are in clinical trial stages such as Atreleuton and Setileuton. So, there is a dire requirement in the area of progress of novel 5-LOX inhibitors which necessitates an understanding of their structure activity relationship and mode of action. In this review, novel 5-LOX inhibitors reported so far, their structural design, SAR and developmental strategies along with clinical updates are discussed over the last two decades.

Novel 3,4-Dihydroisocoumarins Inhibit Human P-gp and BCRP in Multidrug Resistant Tumors and Demonstrate Substrate Inhibition of Yeast Pdr5

Multidrug resistance (MDR) in tumors and pathogens remains a major problem in the efficacious treatment of patients by reduction of therapy options and subsequent treatment failure. Various mechanisms are described to be involved in the development of MDR with overexpression of ATP-binding cassette (ABC) transporters reflecting the most extensively studied. These membrane transporters translocate a wide variety of substrates utilizing energy from ATP hydrolysis leading to decreased intracellular drug accumulation and impaired drug efficacy. One treatment strategy might be inhibition of transporter-mediated efflux by small molecules. Isocoumarins and 3,4-dihydroisocoumarins are a large group of natural products derived from various sources with great structural and functional variety, but have so far not been in the focus as potential MDR reversing agents. Thus, three natural products and nine novel 3,4-dihydroisocoumarins were designed and analyzed regarding cytotoxicity induction and inhibition of human ABC transporters P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) in a variety of human cancer cell lines as well as the yeast ABC transporter Pdr5 in Saccharomyces cerevisiae. Dual inhibitors of P-gp and BCRP and inhibitors of Pdr5 were identified, and distinct structure-activity relationships for transporter inhibition were revealed. The strongest inhibitor of P-gp and BCRP, which inhibited the transporters up to 80 to 90% compared to the respective positive controls, demonstrated the ability to reverse chemotherapy resistance in resistant cancer cell lines up to 5.6-fold. In the case of Pdr5, inhibitors were identified that prevented substrate transport and/or ATPase activity with IC₅₀ values in the low micromolar range. However, cell toxicity was not observed. Molecular docking of the test compounds to P-gp revealed that differences in inhibition capacity were based on different binding affinities to the transporter. Thus, these small molecules provide novel lead structures for further optimization.

A novel class of tyrosine derivatives as dual 5-LOX and COX-2/mPGES1 inhibitors with PGE2 mediated anticancer properties

Leukotriene and prostaglandin pathways are controlled by the enzymes, LOX and COX/mPGES1 respectively and are responsible for inflammatory responses.

Synthesis of diarylidenecyclohexanone derivatives as potential anti-inflammatory leads against COX-2/mPGES1 and 5-LOX

This study establishes the diarylidenecyclohexanones as good anti-inflammatory pharmacophores with selective high potency against PGE₂and 5-LOX without toxicity towards healthy human cells.

Recent advances in the search for novel 5-lipoxygenase inhibitors for the treatment of asthma

The products of 5-lipoxygenase are synthesized and released in the airway when an asthmatic reaction occurs. 5-lipoxygenase via arachidonic acid metabolism produces leukotrienes that mediate bronchoconstriction and inflammatory modifications essential in the pathophysiology of asthma. Until to now, only one approved 5-LO inhibitor, zileuton, can be found as a potential therapy for asthma. With the increasing number of indications for anti-leukotriene (anti-LT) drugs, the development of 5-LO inhibitor agents becomes increasingly important. The present MiniReview reports an update on 5-LO inhibitors currently under clinical investigation. In addition, the latest advances focused on the development of new 5-lipoxygenase inhibitors as asthma anti-inflammatory agents are also discussed.