Synthesis, characterization, hypoglycemic and aldose reductase inhibition activity of arylsulfonylspiro[fluorene-9,5′-imidazolidine]-2′,4′-diones

Formation of Fluorovinyl Spiro-[imidazole-indene] and α-Amino-β-naphthalenones via Rh(III)-Catalyzed Cascade C-H Functionalization

An efficacious method for building fluorovinyl spiro-[imidazole-indene] and α-amino-β-naphthalenone skeletons synchronously has been shown to consist of Rh(III)-catalyzed C-H functionalization between 2H-imidazoles and difluoromethylene alkynes. This protocol demonstrates a practical and straightforward route for installing fluorine elements in the envisioned position of heterocyclic compounds.

Cu-Catalyzed synthesis of spiroimidazole derivatives via an indolyl mediated cyclization–rearrangement reaction

A novel Cu-catalyzed synthesis of structurally valuable spiroimidazole derivatives from 2-(indol-3-yl)cyclohexanones and amidines via an indolyl mediated cyclization–rearrangement reaction is described.

Biological effects of bis-hydrazone compounds bearing isovanillin moiety on the aldose reductase

Aldose reductase (ALR2), one of the metabolically important enzymes, catalyzes the formation of sorbitol from glucose in the polyol pathway. ALR2 inhibition is required to prevent diabetic complications. In the present study, the novel bis-hydrazone compounds bearing isovanillin moiety (GY1-12) were synthesized, and various chromatographic methods were applied to purify the ALR2 enzyme. Afterward, the inhibitory effect of the synthesized compounds on the ALR2 was screened in vitro. All the novel bis-hydrazones demonstrated activity in nanomolar levels as AR inhibitors with IC₅₀ and K_I values in the range of 12.55-35.04 nM, and 13.38-88.21 nM, respectively. Compounds GY-11, GY-7, and GY-5 against ALR2 were identified as the highly potent inhibitors, respectively, and were superior to the standard drug, epalrestat. Moreover, a comprehensive ligand-receptor interactions prediction was performed using ADME-Tox, Glide XP, and MM-GBSA modules of Schrödinger Small-Molecule Drug Discovery Suite to elucidate the novel bis-hydrazone derivatives, potential binding modes versus the ALR2. As a result, these compounds with ALR2 inhibitory effects may be potential alternative agents that can be used to treat or prevent diabetic complications.

Synthesis, molecular modeling, selective aldose reductase inhibition and hypoglycemic activity of novel meglitinides

In the present study, a novel generation of selective aldose reductase ALR2 inhibitors with significant hypoglycemic activities was designed and modulated based on rhodanine scaffold joined to an acetamide linker in between two lipophilic moieties. The synthesis of the novel compounds was accomplished throughout simple chemical pathways. Molecular docking was performed on B-cell membrane protein SUR1, aldehyde reductase ALR1 and aldose reductase ALR2 active sites. Compounds 10B, 11B, 12B, 15C, 16C, 26F and 27F displayed the highest hypoglycemic activities with 80.7, 85.2, 87, 82.3, 83.5, 81.4 and 85.3% reduction in blood glucose levels, respectively. They were more potent than the standard hypoglycemic agent repaglinide with 65.4% reduction in blood glucose level. Compounds 12B and 15C with IC₅₀ 0.29 and 0.35 µM were more potent than the standard ALR2 inhibitor epalrestat with IC₅₀ 0.40 µM. They were selective towards ALR2 over ALR1 134 and 116 folds, respectively. Molecular docking studies matched with the in-vitro and in-vivo results to elucidate the dual activities of both compounds 12B and 15C as potent antagonists for ALR2 over ALR1 and good agonists for the SUR1 protein.

Synthesis and Biological Activity Evaluation of Polyfunctionalized Anthraquinonehydrazones

Background :

Anthraquinone derivatives, frequently occurring motifs in many various natural compounds, have attracted a great deal of interest as compounds with a wide spectrum of biological activities.

Introduction:

The hybrid pharmacophore approach has become an object of considerable interest due to the incorporation of a five- or six-membered heterocyclic rings in the structure of various natural compounds, especially anthraquinone derivatives.

Methods:

A series of polyfunctionalized anthraquinonehydrazones have been synthesized via the azo-coupling reaction between anthraquinone-based triazenes and methylene active compounds. The structures of synthesized compounds were confirmed by spectral data. Some of the synthesized compounds were screened for their in vitro anticancer activity according to US NCI protocols. The screening of antimicrobial and antifungal activities against Candida albicans and Lactobacillus sp. was carried out. The synthesized compounds were evaluated for their antioxidant (DPPH free radical scavenging assay) and herbicidal activity.

Results:

The synthesized 1-[N'-(5-oxo-2-thioxoimidazolidin-4-ylidene)-hydrazino]-anthraquinone 1.5 displayed a high level of antimitotic activity against tested human tumor cells with mean GI50/TGI values 4.06/78.52μM. The screening of antimicrobial and antifungal activities led to the identification of 1.8 and 1.9 with a moderate effect on Candida albicans and Lactobacillus sp. Antioxidant activity evaluation allowed the identification of 1-[N'-(3-methyl-5-oxo-1-phenyl-1,5- dihydropyrazol-4-ylidene)-hydrazino]-anthraquinone 1.8 with an IC50 value of 3.715 mM. The herbicidal activity screening led to compound identification 1.8 with growth inhibition of Agrostis stolonifera at 25 %.

Conclusion:

The obtained anthraquinonehydrazones constitute an interesting template for the design of new synthetic agents with polypharmacological activities.

Multifunctional agents based on benzoxazolone as promising therapeutic drugs for diabetic nephropathy

Diabetic nephropathy (DN) is resulted from activations of polyol pathway and oxidative stress by abnormal metabolism of glucose, and no specific medication is available. We designed a novel class of benzoxazolone derivatives, and a number of individuals were found to have significant antioxidant activity and inhibition of aldose reductase of the key enzyme in the polyol pathway. The outstanding compound (E)-2-(7-(4-hydroxy-3-methoxystyryl)-2-oxobenzo[d]oxazol-3(2H)-yl)acetic acid was identified to reduce urinary proteins in diabetic mice suggesting an alleviation in the diabetic nephropathy, and this was confirmed by kidney hematoxylin-eosin staining. Further investigations showed blood glucose normalization, declined in the polyol pathway and lipid peroxides, and raised glutathione and superoxide dismutase activity. Thus, we suggest a therapeutic function of the compound for DN which could be attributed to the combination of hypoglycemic, aldose reductase inhibition and antioxidant.

High-sensitive detection of fluorene by ambient ionization mass spectrometry

High sensitive analysis for fluorene at the sub-ng L⁻¹ level in real water samples was achieved by nebulization-dielectric barrier discharge ionization.

Aldose reductase and protein tyrosine phosphatase 1B inhibitors as a promising therapeutic approach for diabetes mellitus

Diabetes mellitus is a metabolic disease characterized by high blood glucose levels and usually associated with several chronic pathologies. Aldose reductase and protein tyrosine phosphatase 1B enzymes have identified as two novel molecular targets associated with the onset and progression of type II diabetes and related comorbidities. Although many inhibitors against these enzymes have already found in the field of diabetic mellitus, the research for discovering more effective and selective agents with optimal pharmacokinetic properties continues. In addition, dual inhibition of these target proteins has proved as a promising therapeutic approach. A variety of diverse scaffolds are presented in this review for the future design of potent and selective inhibitors of aldose reductase and protein tyrosine phosphatase 1B based on the most important structural features of both enzymes. The discovery of novel dual aldose reductase and protein tyrosine phosphatase 1B inhibitors could be effective therapeutic molecules for the treatment of insulin-resistant type II diabetes mellitus. The methods used comprise a literature survey and X-ray crystal structures derived from Protein Databank (PDB). Despite the available therapeutic options for type II diabetes mellitus, the inhibitors of aldose reductase and protein tyrosine phosphatase 1B could be two promising approaches for the effective treatment of hyperglycemia and diabetes-associated pathologies. Due to the poor pharmacokinetic profile and low in vivo efficacy of existing inhibitors of both targets, the research turned to more selective and cell-permeable agents as well as multi-target molecules.

Design, synthesis, in vitro and in silico investigation of aldose reductase inhibitory effects of new thiazole-based compounds

Aldose reductase (AR) catalyzes the NADPH-dependent reduction of glucose to sorbitol in the polyol pathway, which plays an important role in the development of diabetic complications including cataract, retinopathy, nephropathy, and neuropathy. AR has been considered as an important target to heal these long-term diabetic complications and for this reason the development of new AR inhibitors is an important approach in modern medicinal chemistry. In the current study, new 4-aryl-2-[2-((3,4-dihydro-2H-1,5-benzodioxepine-7-yl)methylene)hydrazinyl]thiazole derivatives (1-12) were synthesized and screened for their inhibitory effects on AR which was purified by diverse chromatographic methods with a yield of 1.40% and a specific activity of 2.00 EU/mg. All compounds were determined as promising AR inhibitors with the K_i values in the range of 0.018 ± 0.005 μM-3.746 ± 1.321 μM compared to the quercetin (K_i = 7.025 ± 1.780 μM). In particular, 4-(4-cyanophenyl)-2-[2-((3,4-dihydro-2H-1,5-benzodioxepin-7-yl)methylene)hydrazinyl]thiazole (3) was detected as the most potential AR inhibitor in this series with the K_i value of 0.018 ± 0.005 µM and the compound showed competitive AR inhibition. The cytotoxic effects of compounds 1-12 were investigated on L929 mouse fibroblast (healthy) cells using MTT assay and all these compounds were defined as non-cytotoxic agents against L929 cells. Molecular docking studies, which were employed to determine the affinity of compounds 1-12 into the active site of AR, highlighted that the thiazole scaffold of all these compounds presented π-π stacking interactions with Trp20 and Phe122. According to both in vitro and in silico assays, these potential AR inhibitors may have great importance in the prevention of diabetic microvascular conditions.

Addressing selectivity issues of aldose reductase 2 inhibitors for the management of diabetic complications

Aldose Reductase 2 (ALR2), the rate-limiting enzyme of the polyol pathway, plays an important role in detoxification of some toxic aldehydes. Under hyperglycemia, this enzyme overactivates and causes diabetic complications (DC). Therefore, ALR2 inhibition has been established as a potential approach to manage these complications. Several ALR2 inhibitors have been reported, but none of them could reach US FDA approval. One of the main reasons is their poor selectivity over ALR1, which leads to the toxicity. The current review underlines the molecular connectivity of ALR2 with DC and comparative analysis of the catalytic domains of ALR2 and ALR1, to better understand the selectivity issues. This report also discusses the key features required for ALR2 inhibition and to limit toxicity due to off-target activity.

Anticancer activity studies of novel metal complexes of ligands derived from polycyclic aromatic compound via greener route

Methoxy and tert-butyl substituted carboxamide, carboxylic acid and hydrazone Schiff base groups have been assembled into our newly designed fluorenone based ligands and prepared coordination compounds of some first row transition metals and characterized thoroughly with spectroscopic (¹H and ¹³C NMR, IR, GC–MS, UV–Vis), analytical, TGA and molar conductance measurements. The stoichiometry of all the metal complexes is found to be 1: 2 (M: L₂) with the general formula, [M(L)₂], where L is a singly deprotonated ligand and the geometry of all the metal complexes is found to be octahedral. Ligands and their metal complexes successfully cleaved the pBR322 plasmid DNA and in case of anticancer activity against MCF–7 (human breast adenocarcinoma) cell line, the synthesized compounds found to exhibit excellent activity with prominent apoptotic effect which is characterized by cell shrinkage, cell breakage and turgidity and results were compared with the standard drug cisplatin. Very significant anticancer activity was observed for compounds L¹H, Cu(L¹)₂, Cu(L²)₂, Ni(L¹)₂ and Ni(L²)₂ with IC₅₀ value of <10 μgmL⁻¹. Molecular docking studies were performed to assess the bonding mode of synthesized compounds. In case of antioxidant activity study, the compounds L¹H, Ni(L¹)₂, Ni(L²)₂, Cu(L¹)₂ and Cu(L²)₂ exhibited significant scavenging activity with good percentage when compared with remaining tested compounds.

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The manuscript describes the synthesis of two new hydrazone Schiff base ligands.

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Synthesis of metal complexes in water.

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Structure of compounds was confirmed by analytical and spectroscopic methods.

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DNA cleavage, molecular docking and anticancer activity studies were carried out.

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Cu(II) and Ni(II) complexes show excellent anticancer activity (IC₅₀ < 10 μgmL⁻¹).

Anti-diabetic drugs recent approaches and advancements

Diabetes is one of the major diseases worldwide and is the third leading cause of death in the United States. Anti-diabetic drugs are used in the treatment of diabetes mellitus to control glucose levels in the blood. Most of the drugs are administered orally, except for a few of them, such as insulin, exenatide, and pramlintide. In this review, we are going to discuss seven major types of anti-diabetic drugs: Peroxisome proliferator-activated receptor (PPAR) agonist, protein tyrosine phosphatase 1B (PTP1B) inhibitors, aldose reductase inhibitors, α-glucosidase inhibitors, dipeptidyl peptidase IV (DPP-4) inhibitors, G protein-coupled receptor (GPCR) agonists and sodium-glucose co-transporter (SGLT) inhibitors. Here, we are also discussing some of the recently reported anti-diabetic agents with its multi-target pharmacological actions. This review summarises recent approaches and advancement in anti-diabetes treatment concerning characteristics, structure-activity relationships, functional mechanisms, expression regulation, and applications in medicine.

Pharmaceutical and medicinal significance of sulfur (SVI)-Containing motifs for drug discovery: A critical review

Sulfur (S^VI) based moieties, especially, the sulfonyl or sulfonamide based analogues have showed a variety of pharmacological properties, and its derivatives propose a high degree of structural diversity that has established useful for the finding of new therapeutic agents. The developments of new less toxic, low cost and highly active sulfonamides containing analogues are hot research topics in medicinal chemistry. Currently, more than 150 FDA approved Sulfur (S^VI)-based drugs are available in the market, and they are widely used to treat various types of diseases with therapeutic power. This comprehensive review highlights the recent developments of sulfonyl or sulfonamides based compounds in huge range of therapeutic applications such as antimicrobial, anti-inflammatory, antiviral, anticonvulsant, antitubercular, antidiabetic, antileishmanial, carbonic anhydrase, antimalarial, anticancer and other medicinal agents. We believe that, this review article is useful to inspire new ideas for structural design and developments of less toxic and powerful Sulfur (S^VI) based drugs against the numerous death-causing diseases.

Synthesis of new chiral 1,3,4-thiadiazole-based di- and tri-arylsulfonamide residues and evaluation of in vitro anti-HIV activity and cytotoxicity

A series of new chiral 1,3,4-thiadiazole-based bis-sulfonamides 4a-4w and tri-sulfonamide analogue 5 was synthesized and evaluated as anti-HIV agents. The reaction of chiral amino acids 1 with sulfonyl chlorides 2, followed by subsequent reaction of resultant N-protected amino acids 2a-2f with thiosemicarbazide in the presence of excess phosphorous oxychloride afforded N-(1-(5-amino-1,3,4-thiadiazol-2-yl)alkyl)-4-arylsulfonamides 3a-3f. Treatment of 2a-2f with substituted sulfonyl chlorides in portions furnished the target bis-sulfonamide analogues 4a-4w in good yields, together with the unexpected 5. The new compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compounds 4s were the most active in inhibiting HIV-1 with IC₅₀ = 9.5 μM (SI = 6.6), suggesting to be a new lead in the development of an antiviral agent. Interestingly, compound 5 exhibited significant cytotoxicity of > 4.09 μM and could be a promising antiproliferative agent.

Current anti-diabetic agents and their molecular targets: A review

Diabetes mellitus is a medical condition characterized by the body's loss of control over blood sugar. The frequency of diagnosed cases and consequential increases in medical costs makes it a rapidly growing chronic disease that threatens human health worldwide. In addition, its unnerving statistical projections are perilous to both the economy of the nation and man's life expectancy. Type-I and type-II diabetes are the two clinical forms of diabetes mellitus. Type-II diabetes mellitus (T2DM) is illustrated by the abnormality of glucose homeostasis in the body, resulting in hyperglycemia. Although significant research attention has been devoted to the development of diabetes regimens, which demonstrates success in lowering blood glucose levels, their efficacies are unsustainable due to undesirable side effects such as weight gain and hypoglycemia. Over the years, heterocyclic scaffolds have been the basis of anti-diabetic chemotherapies; hence, in this review we consolidate the use of bioactive scaffolds, which have been evaluated for their biological response as inhibitors against their respective anti-diabetic molecular targets over the past five years (2012-2017). Our investigation reveals a diverse target set which includes; protein tyrosine phosphatase 1 B (PTP1B), dipeptidly peptidase-4 (DPP-4), free fatty acid receptors 1 (FFAR1), G protein-coupled receptors (GPCR), peroxisome proliferator activated receptor-γ (PPARγ), sodium glucose co-transporter-2 (SGLT2), α-glucosidase, aldose reductase, glycogen phosphorylase (GP), fructose-1,6-bisphosphatase (FBPase), glucagon receptor (GCGr) and phosphoenolpyruvate carboxykinase (PEPCK). This review offers a medium on which future drug design and development toward diabetes management may be modelled (i.e. optimization via structural derivatization), as many of the drug candidates highlighted show promise as an effective anti-diabetic chemotherapy.

Regulation on SIRT1-PGC-1α/Nrf2 pathway together with selective inhibition of aldose reductase makes compound hr5F a potential agent for the treatment of diabetic complications

(R,E)-N-(3-(2-acetamido-3-(benzyloxy) propanamido)propyl)-2-cyano-3-(4-hydroxy phenyl)acrylamide (hr5F) was design-synthesized based on bioactivity focus strategy as a potential agent to treat diabetic complicates. With in vitro enzyme assay, it is confirmed that hr5F is an effective ALR2 inhibitor with IC₅₀ value of 2.60 ± 0.15 nM, and selectivity index of 86.0 over ALR1, which is a little bit better than the reference Epalrestat (Epa). hr5F inhibits the increase of ALR2 enzyme activity and expression in human lens epithelial cells (HLECs) induced by high glucose. By applying western blot, it was found that hr5F alleviates the high glucose-induced superoxide overproduction insults by regulating SIRT1-PGC-1α/Nrf2 pathway, together with regulating NRF-1, mtTFA, Bax/Bcl-2 to ameliorate cell apoptosis. The in vivo effects of hr5F on short term streptozocin (STZ)-induced diabetic mice confirm the same functions disclosed in vitro. All the evidences support that hr5F may serve as a promising agent in the treatment of diabetic complications with close efficacy and broader indication than the reference Epa.

Recent Advances in the Synthesis of Hydantoins: The State of the Art of a Valuable Scaffold

The review highlights the hydantoin syntheses presented from the point of view of the preparation methods. Novel synthetic routes to various hydantoin structures, the advances brought to the classical methods in the aim of producing more sustainable and environmentally friendly procedures for the preparation of these biomolecules, and a critical comparison of the different synthetic approaches developed in the last twelve years are also described. The review is composed of 95 schemes, 8 figures and 528 references for the last 12 years and includes the description of the hydantoin-based marketed drugs and clinical candidates.

Identification of novel pyrazole–rhodanine hybrid scaffolds as potent inhibitors of aldose reductase: design, synthesis, biological evaluation and molecular docking analysis

A series of novel pyrazole–rhodanine derivatives was designed, synthesized, and biologically evaluated for their potential inhibitory effect on both aldehyde reductase (ALR1) and aldose reductase (ALR2).

Design, Synthesis and in Vivo Evaluation of Novel Glycosylated Sulfonylureas as Antihyperglycemic Agents

Sulphonylurea compounds have versatile activities such as antidiabetic, diuretic, herbicide, oncolytic, antimalarial, antifungal and anticancer. The present study describes the design, synthesis and in vivo testing of novel glycosylated aryl sulfonylurea compounds as antihyperglycaemic agents in streptozocine-induced diabetic mice. The rational for the introduction of the glucosamine moiety is to enhance selective drug uptake by pancreatic β-cells in order to decrease the cardiotoxic side effect commonly associated with sulfonylurea agents. 2-Deoxy-2-(4-chlorophenylsulfonylurea)-d-glucopyranose was found to be the most potent antihyperglycaemic agents among the synthesized compounds in diabetic mice. This investigation indicates the importance of this novel class as potential antihyperglycaemic agents.