Synthesis of novel indenoquinoxaline derivatives as potent α-glucosidase inhibitors

Exploring the interaction between calf thymus DNA and 11H-Indeno[1,2-b]quinoxalin-11-one Thiosemicarbazones: Spectroscopies and in vitro antitumor activity

Understanding the interactions between small molecules and calf thymus deoxyribonucleic acid (ctDNA) is critical for certain aspects of drug discovery. In this study, three 11H-indeno[1,2-b]quinoxalin-11-one thiosemicarbazones were synthesized and their interaction with ctDNA was examined through various spectroscopic techniques, including ultraviolet (UV) spectroscopy, fluorescence spectroscopy, and circular dichroism (CD) spectrum, and through physicochemical methods, including viscosity measurements. In addition, the effects of these thiosemicarbazone compounds 4a, 4b and 4c on several cancer cell lines were explored. The results of UV absorption, fluorescence quenching and CD experiments indicated that compounds 4a, 4b and 4c primarily bound to ctDNA by an intercalation. This mode of interaction was further corroborated by viscosity measurements. Docked poses of compound 4a revealed that it formed a crucial N position hydrogen bond with the DNA receptor. The chemical structure of compound 4a was further confirmed by X-ray crystallographic analysis. Through biological evaluation, it was found that the in vitro cytotoxicity of three compounds agreed with the order of their binding strength to ctDNA, indicating that the antitumor activity of these compounds correlated with their binding affinity to ctDNA.

Design, synthesis, anti-mycobacterial activity, molecular docking and ADME analysis of spiroquinoxaline-1,2,4-oxadiazoles via [3 + 2] cycloaddition reaction under ultrasound irradiation

The development of anti-tuberculosis (anti-TB) drugs has become a challenging task in medicinal chemistry. This is because Mycobacterium tuberculosis (TB), the pathogen that causes tuberculosis, has an increasing number of drug-resistant strains, and existing medication therapies are not very effective. This resistance significantly demands new anti-TB drug profiles. Here, we present the design and synthesis of a number of hybrid compounds with previously known anti-mycobacterial moieties attached to quinoxaline, quinoline, tetrazole, and 1,2,4-oxadiazole scaffolds. A convenient ultrasound methodology was employed to attain spiroquinoxaline-1,2,4-oxadiazoles via [3 + 2] cycloaddition of quinoxaline Schiff bases and aryl nitrile oxides at room temperature. This approach avoids standard heating and column chromatography while producing high yields and shorter reaction times. The target compounds 3a-p were well-characterized, and their in vitro anti-mycobacterial activity (anti-TB) was evaluated. Among the screened compounds, 3i displayed promising activity against the Mycobacterium tuberculosis cell line H37Rv, with an MIC99 value of 0.78 µg/mL. However, three compounds (3f, 3h, and 3o) exhibited potent activity with MIC99 values of 6.25 µg/mL. To further understand the binding interactions, the synthesized compounds were docked against the tuberculosis protein 5OEQ using in silico molecular docking. Moreover, the most active compounds were additionally tested for their cytotoxicity against the RAW 264.7 cell line, and the cytotoxicity of compounds 3f, 3h, 3i, and 3o was 27.3, 28.9, 26.4, and 30.2 µg/mL, respectively. These results revealed that the compounds 3f, 3h, 3i, and 3o were less harmful to humans. Furthermore, the synthesized compounds were tested for ADME qualities, and the results suggest that this series is useful for producing innovative and potent anti-tubercular medicines in the future.

Pharmacophore-based 3D-QSAR modeling, virtual screening, docking, molecular dynamics and biological evaluation studies for identification of potential inhibitors of alpha-glucosidase

CONTEXT

Alpha-glucosidase enzyme is considered an important therapeutic target for controlling hyperglycemia associated with type 2 diabetes. Novel scaffolds identified as potential alpha-glucosidase inhibitors from the Maybridge library utilizing pharmacophore modeling, molecular docking and biological evaluation are reported in this manuscript.

METHOD

A total of 51 xanthone series scaffolds previously reported as alpha-glucosidase inhibitors were collected and used as training and test sets. These sets were employed to develop and validate a pharmacophore-based 3D-QSAR model with statistically meaningful results using Schrodinger software. The model showed a high F value (F, 80.1) at five component partial least square factors, a high cross-validation coefficient (Q2, 0.66) and a good correlation coefficient (R2, 0.95). Pearson correlation coefficient (r) of 0.8400 indicated a greater degree of confidence in the model. Subsequently, virtual screening was performed with PHASE module of Schrodinger software using the above model to identify novel alpha-glucosidase inhibitors, and mapped compounds were evaluated for their interactions with the protein. The X-ray co-crystallised structure of the alpha-glucosidase protein in complex with acarbose (PDB Code: 5NN8) was used for molecular docking analysis using GLIDE module and a total of eight compounds were further selected for biological evaluation. Molecular dynamics analysis using GROMACS software was performed in the active site of alpha-glucosidase protein to gain insights into binding mechanism of the four active compounds which were finally found to exhibit inhibitory activity in the biological assay.

Photoredox-Catalyzed Cross-Coupling of In Situ Generated Quinoxalinones with Indoles for the Synthesis of Tertiary Alcohols

A visible light-driven photoredox-catalyzed direct C(sp2)-H functionalization of N-H free indoles with quinoxalinones generated in situ from 2,2-dihydroxy-1H-indene-1,3(2H)-dione and phenylene-1,2-diamines has been reported with the aid of Na2-Eosin Y as the photocatalyst and the Hünig base as the sacrificial electron and proton donor. The reaction provides easy access to a variety of quaternary-centered C-3 selective indole-substituted tertiary alcohols in good yields. Mechanistic studies demonstrated the realization of photoredox-catalyzed in situ quinoxalinone formation and their proton-coupled single electron reduction to the corresponding ketyl radicals followed by cross-coupling with indoles. The potential applications of the synthesized tertiary alcohols in photoacid-catalyzed carbon-carbon and carbon-sulfur bond-forming reactions feature the key findings of the present work.

Indenoquinoxaline-phenylacrylohydrazide hybrids as promising drug candidates for the treatment of type 2 diabetes: In vitro and in silico evaluation of enzyme inhibition and antioxidant activity

Existing drugs that are being used to treat type-2 diabetes mellitus are associated with several side effects; thus, exploring potential drug candidates is still an utter need these days. Hybrids of indenoquinoxaline and hydrazide have never been explored as antidiabetic agents. In this study, a series of new indenoquinoxaline-phenylacrylohydrazide hybrids (1-30) were synthesized, structurally characterized, and evaluated for α-amylase and α-glucosidase inhibitory activities, as well as for their antioxidant properties. All scaffolds exhibited varying degrees of inhibitory activity against both enzymes, with IC50 values ranging from 2.34 to 61.12 μM for α-amylase and 0.42 to 54.72 μM for α-glucosidase. Particularly, compounds 10, 16, 17, 18, 24, and 25 demonstrated the highest efficacy in inhibiting α-amylase, while compounds 6, 7, 8, 10, 12, 14, 13, 16, 17, 18, 24, and 25 were the most effective α-glucosidase inhibitors, compared to standard acarbose. Moreover, most of these compounds displayed substantial antioxidant potential compared to standard butylated hydroxytoluene (BHT). Kinetics studies revealed competitive inhibition modes by compounds. Furthermore, a comprehensive in silico study and toxicity prediction were also conducted, further validating these analogs as potential drug candidates. The structured compounds demonstrated enhanced profiles, underscoring their potential as primary candidates in drug discovery.

A Focussed Analysis of β-cyclodextrins for Quinoxaline Derivatives Synthesis

Abstract:

Cyclodextrins (CDs), which are a type of cyclic oligosaccharides, are widely used in supramolecular chemistry. For example, they can be used to encapsulate volatile compounds, such as drugs, within their hydrophobic cavity. This encapsulation reduces the volatility of the compounds and helps to retain their desired properties. Due to its extraordinary properties, cyclodextrins have been utilized as catalysts in numerous organic synthesis processes. An intrinsic objective of organic chemists is to optimize the efficacy of organic synthesis through the mitigation of chemical waste and energy expenditure. Utilizing water as a green solvent is, therefore, economical, environmentally sustainable, and secure. It appears that employing water in conjunction with a recyclable catalyst is the most effective method for supramolecular catalysis. As a consequence, we focused this review on the use of water as a solvent and cyclodextrin as a polymer catalyst to produce quinoxaline derivatives in an environmentally friendly and sustainable manner.

Synthesis, biological activities, and evaluation molecular docking-dynamics studies of new phenylisoxazole quinoxalin-2-amine hybrids as potential α-amylase and α-glucosidase inhibitors

New phenylisoxazole quinoxalin-2-amine hybrids 5a-i were successfully synthesised with yields of 53-85% and characterised with various spectroscopy methods. The synthesised hybrids underwent in vitro α-amylase and α-glucosidase inhibitory assays, with acarbose as the positive control. Through the biological study, compound 5h exhibits the highest α-amylase inhibitory activity with IC50 = 16.4 ± 0.1 μM while compounds 5a-c, 5e and 5h exhibit great potential as α-glucosidase inhibitors, with 5c being the most potent (IC50 = 15.2 ± 0.3 μM). Among the compounds, 5h exhibits potential as a dual inhibitor for both α-amylase (IC50 = 16.4 ± 0.1 μM) and α-glucosidase (IC50 = 31.6 ± 0.4 μM) enzymes. Through the molecular docking studies, the inhibition potential of the selected compounds is supported. Compound 5h showed important interactions with α-amylase enzyme active sites and exhibited the highest binding energy of -8.9 ± 0.10 kcal mol-1, while compound 5c exhibited the highest binding energy of -9.0 ± 0.20 kcal mol-1 by forming important interactions with the α-glucosidase enzyme active sites. The molecular dynamics study showed that the selected compounds exhibited relative stability when binding with α-amylase and α-glucosidase enzymes. Additionally, compound 5h demonstrated a similar pattern of motion and mechanism of action as the commercially available miglitol.

Development of new spiro[1,3]dithiine-4,11'-indeno[1,2-b]quinoxaline derivatives as S. aureus Sortase A inhibitors and radiosterilization with molecular modeling simulation

Multi-drug resistant microbes have become a severe threat to human health and arise a worldwide concern. A total of fifteen spiro-1,3-dithiinoindenoquinoxaline derivatives 2-7 were synthesized and evaluated for their biological activities against five standard and MDRB pathogens. The MIC and MBC/MFC for the most active derivatives were determined in vitro via broth microdilution assay. These derivatives showed significant activity against the tested strains with microbicidal behavior, with compound 4b as the most active compound (MIC range between 0.06 and 0.25 µg/mL for bacteria strains and MIC = 0.25 µg/mL for C. albicans). The most active spiro-1,3-dithiinoindenoquinoxaline derivatives were able to inhibit the activity of SrtA with IC₅₀ values ranging from 22.15 ± 0.4 µM to 37.12 ± 1.4 µM. In addition, the active spiro-1,3-dithiinoindenoquinoxaline attenuated the in vitro virulence-related phenotype of SrtA by weakening the adherence of S. aureus to fibrinogen and reducing the biofilm formation. Surprisingly, compound 4b revealed potent SrtA inhibitory activity with IC₅₀ = 22.15 µM, inhibiting the adhesion of S. aureus with 39.22 ± 0.15 % compared with untreated 9.43 ± 1.52 %, and showed a reduction in the biofilm biomass of S. aureus with 32.27 ± 0.52 %. We further investigated the effect of gamma radiation as a sterilization method on the microbial load and found that a dose of 5 kGy was sufficient to eradicate the microbial load. The quantum chemical studies exhibited that the tested derivatives have a small energy band gap (ΔE = -2.95 to -3.61 eV) and therefore exert potent bioactivity by interacting with receptors more stabilizing.

New multicomponent reactions in water: a facile synthesis of 1,3-dioxo-2-indanilidene-heterocyclic scaffolds and indenoquinoxalines through reaction of ninhydrin-malononitrile adduct with diverse N-binucleophiles

We report here a highly efficient green approach for the synthesis of imidazolidin-2-ylidene-indenedione, pyrimidine-2-ylidene-indenedione and indenoquinoxaline derivatives through the one-pot three-component reaction between ninhydrin, malononitrile and various diamines in water medium under catalyst-free conditions. High yields (73-98%) of the target products were achieved with short reaction times at room temperature. Simple workup, no column chromatography, good to excellent yields, rapid reaction and green solvent are the prominent advantages of this protocol.

Inhibitory potential of phenolic compounds of Thai colored rice (Oryza sativa L.) against α-glucosidase and α-amylase through in vitro and in silico studies

BACKGROUND

This study investigated the inhibitory efficiency of phenolic compounds content methyl vanillate, syringic acid and vanillic acid against α-glucosidase and α-amylase. The phenolic compound contents of 10 Thai colored rice cultivars were also determined, and the relationship between the inhibitory efficiency of colored rice extract with methyl vanillate, syringic acid and vanillic acid was evaluated.

RESULTS

The results revealed that the inhibition efficiency of methyl vanillate, syringic acid and vanillic acid was higher against α-glucosidase than against α-amylase. Inhibitory activity of vanillic acid against α-glucosidase and α-amylase was highest, with IC₅₀ of 0.100 ± 0.01 and 0.130 ± 0.02 mmol L^-1 , respectively. Docking study showed strong binding by three hydrogen bonds and four hydrogen bonds between vanillic acid with the amino acid in the binding site of α-glucosidase and α-amylase, respectively. Inhibition modes of these phenolic compounds were defined as a mixed type inhibition against α-glucosidase. Highest phenolic compound contents of methyl vanillate, syringic acid and vanillic acid were obtained from methanol extracts of all rice cultivars. The methanol extracts of all colored rice cultivars such as Khao Leum Pua also showed the highest inhibition potential against α-glucosidase and α-amylase. The results indicated that these phenolic compound contents were closely related to the inhibition potential of colored rice extracts against α-glucosidase and α-amylase.

CONCLUSION

Our results suggest that rice, especially colored rice cultivars, has the source of phenolic compounds. Moreover, the phenolic compounds had the greatest source of natural inhibitor against α-glucosidase and α-amylase. © 2022 Society of Chemical Industry.

Design, synthesis, and molecular docking studies of diphenylquinoxaline-6-carbohydrazide hybrids as potent α-glucosidase inhibitors

A novel series of diphenylquinoxaline-6-carbohydrazide hybrids 7a-o were rationally designed and synthesized as anti-diabetic agents. All synthesized compounds 7a-o were screened as possible α-glucosidase inhibitors and exhibited good inhibitory activity with IC50 values in the range of 110.6 ± 6.0 to 453.0 ± 4.7 µM in comparison with acarbose as the positive control (750.0 ± 10.5 µM). An exception in this trend came back to a compound 7k with IC50 value > 750 µM. Furthermore, the most potent derivative 7e bearing 3-fluorophenyl moiety was further explored by kinetic studies and showed the competitive type of inhibition. Additionally, the molecular docking of all derivatives was performed to get an insight into the binding mode of these derivatives within the active site of the enzyme. In silico assessments exhibited that 7e was well occupied in the binding pocket of the enzyme through favorable interactions with residues, correlating to the experimental results.

New styrylquinoxaline: synthesis, structural, biological evaluation, ADMET prediction and molecular docking investigations

The organic compound (E)-3-(4-methylstyryl)quinoxalin-2(1H)-one (SQO) with molecular formula C₁₇H₁₄N₂O was synthesized and analyzed using single crystal X-ray diffraction, ¹H, ¹³C NMR and FTIR spectroscopic techniques. The geometric parameters of the molecule was optimized by density-functional theory (DFT) choosing B3LYP with 6-31++G(d,p) basis set. For compatibility, the theoretical structure and experimental structure were overlapped with each other. Frontier molecular orbitals of the title compound were made, and energy gap between HOMO and LUMO was calculated. Molecular electrostatic potential map was generated finding electrophilic and nucleophilic attack centers using DFT method. Hirshfeld surface analysis (HSA) confirms active regions at the circumference of N1 atoms and O1 atoms that form intermolecular N1-H1···O1 hydrogen bond. The acute oral toxicity study was carried out according to OECD guideline, which approve that the compound SQO was non-toxic. In addition, this quinoxaline derivative was evaluated for its in vitro antidiabetic activity against α-glucosidase and α-amylase enzymes and for antioxidant activity by utilizing several tests as 1,1-diphenyl-2-picryl hydrazyl, (2,2'-azino-bis(3-ethyl benzthiazoline-6-sulfonicacid), reducing power test (FRAP) and hydrogen peroxide activity H₂O₂. The molecular docking studies were performed to investigate the antidiabetic activity of SQO and compared with the experimental results. SQO is a potent antidiabetic from both the experimental and molecular docking results. Finally, the physicochemical, pharmacokinetic and toxicological properties of SQO have been evaluated by using in silico absorption, distribution, metabolism, excretion and toxicity analysis prediction.

Green Synthesis of Indeno[1,2-b]quinoxalines Using β-Cyclodextrin as Catalyst

An efficient, mild, and green method was developed for the synthesis of indeno[1,2-b]quinoxaline derivatives via o-phenylenediamine (OPD) and 2-indanone derivatives utilizing β-cyclodextrin (β-CD) as the supramolecular catalyst. The reaction can be carried out in water and in a solid state at room temperature. β-CD can also catalyze the reaction of indan-1,2-dione with OPD with a high degree of efficiency. Compared to the reported methods, this procedure is milder, simpler, and less toxic, making it an eco-friendly alternative. In addition, the β-CD can be recovered and reused without the loss of activity.

Heterocyclic compounds as a magic bullet for diabetes mellitus: a review

Diabetes mellitus (DM) is a major metabolic disorder due to hyperglycemia, which is increasing all over the world. From the last two decades, the use of synthetic agents has risen due to their major involvement in curing of chronic diseases including DM. The core skeleton of drugs has been studied such as thiazolidinone, azole, chalcone, pyrrole and pyrimidine along with their derivatives. Diabetics assays have been performed in consideration of different enzymes such as α-glycosidase, α-amylase, and α-galactosidase against acarbose standard drug. The studied moieties were depicted in both models: in vivo as well as in vitro. Molecular docking of the studied compounds as antidiabetic molecules was performed with the help of Auto Dock and molecular operating environment (MOE) software. Amino acid residues Asp349, Arg312, Arg439, Asn241, Val303, Glu304, Phe158, His103, Lys422 and Thr207 that are present on the active sites of diabetic related enzymes showed interactions with ligand molecules. In this review data were organized for the synthesis of heterocyclic compounds through various routes along with their antidiabetic potential, and further studies such as pharmacokinetic and toxicology studies should be executed before going for clinical trials.

Diabetes mellitus (DM) is a major metabolic disorder due to hyperglycemia, which is increasing all over the world.

Synthesis of 2-styryl-quinazoline and 3-styryl-quinoxaline based sulfonate esters via sp3 C-H activation and their evaluation for α-glucosidase inhibition

Synthesis of 2-styryl-quinazolines and 3-styryl-quinoxaline based sulfonates is reported via sp3 C-H functionalization in the presence of triethylamine (10 mol%). The resulting compounds were tested for the α-glucosidase enzyme inhibition...

A General Method for the Synthesis of 11H-Indeno[1,2-B]Quinoxalin- 11-Ones and 6H-Indeno[1,2-B]Pyrido[3,2-E]Pyrazin-6-One Derivatives Using Mandelic Acid as an Efficient Organo-Catalyst at Room Temperature

Aims:

Synthesis of 11H-indeno[1,2-b]quinoxalin-11-ones as well as 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one derivatives under greener conditions.

Background:

Quinoxaline and related skeletons are very common in naturally occurring bioactive compounds.

Objective:

Design a facile, green and organo-catalyzed method for the synthesis of 11H-indeno[1,2-b]quinoxalin-11-ones as well as 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one derivatives.

Methods:

Both the scaffolds were synthesized via the condensation of ninhydrin and o-phenylenediamines or pyridine-2,3-diamines respectively by using a catalytic amount of mandelic acid as an efficient, commercially available, low cost, organo-catalyst in aqueous ethanol at room temperature.

Results:

Mild reaction conditions, use of metal-free organocatalyst, non-toxic solvent, ambient temperature, and no column chromatographic separation are some of the notable advantages of our developed protocol.

Conclusion:

In conclusion, we have developed a simple, mild, facile and efficient method for the synthesis of structurally diverse 11H-indeno[1,2-b]quinoxalin-11-one derivatives via the condensation reactions of ninhydrin and various substituted benzene-1,2-diamines using a catalytic amount of mandelic acid as a commercially available metal-free organo-catalyst in aqueous ethanol at room temperature. Under the same optimized reaction conditions, synthesis of 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one derivatives was also accomplished with excellent yields by using pyridine-2,3-diamines instead of o-phenylenediamine.

Novel Coumarin Containing Dithiocarbamate Derivatives as Potent α-Glucosidase Inhibitors for Management of Type 2 Diabetes

BACKGROUND

α-Glucosidase is a hydrolyzing enzyme that plays a crucial role in the degradation of carbohydrates and starch to glucose. Hence, α-glucosidase is an important target in carbohydrate mediated diseases such as diabetes mellitus.

OBJECTIVE

In this study, novel coumarin containing dithiocarbamate derivatives 4a-n were synthesized and evaluated against α-glucosidase in vitro and in silico.

METHODS

These compounds were obtained from the reaction between 4-(bromomethyl)-7- methoxy-2H-chromen-2-one 1, carbon disulfide 2, and primary or secondary amines 3a-n in the presence of potassium hydroxide and ethanol at room temperature. In vitro α-glucosidase inhibition and kinetic study of these compounds were performed. Furthermore, a docking study of the most potent compounds was also performed by Auto Dock Tools (version 1.5.6).

RESULTS

Obtained results showed that all the synthesized compounds exhibited prominent inhibitory activities (IC50 = 85.0 ± 4.0-566.6 ± 8.6 μM) in comparison to acarbose as a standard inhibitor (IC50 = 750.0 ± 9.0 μM). Among them, the secondary amine derivative 4d with pendant indole group was the most potent inhibitor. Enzyme kinetic study of the compound 4d revealed that this compound competes with a substrate to connect to the active site of α-glucosidase and therefore is a competitive inhibitor. Moreover, a molecular docking study predicted that this compound interacted with the α-glucosidase active site pocket.

CONCLUSION

Our results suggest that the coumarin-dithiocarbamate scaffold can be a promising lead structure for designing potent α-glucosidase inhibitors for the treatment of type 2 diabetes.

Combination effects of rice extract and five aromatic compounds against α-glucosidase, α-amylase and tyrosinase

Rice is a source of bioactive compounds related to human health and has been used for both consumption and traditional medicine. The authors investigated the synergistic and additive effect of rice extract (RE) combined with five aromatic compounds against three enzymes: α-glucosidase, α-amylase and tyrosinase. RE was purified by thin-layer chromatography (TLC) and preparative TLC (PTLC) with different solvent systems. RE had higher α-glucosidase and α-amylase inhibitory activity than the five aromatic compounds, while the five aromatic compounds had higher tyrosinase inhibitory activity than RE. The combination of RE/acarbose produced synergic inhibition of α-glucosidase and α-amylase, whereas RE showed additive inhibition of both enzymes when combined with aromatic compounds. The five aromatic compounds showed additive inhibition of tyrosinase when combined with RE. The combination of 2-methoxy-4-vinylphenol/vanillin/guaiacol produced synergistic inhibition of α-amylase while showing antagonism of α-glucosidase and tyrosinase. Interestingly, the RE produced additive inhibition of α-glucosidase, α-amylase and tyrosinase when combined with the 2-methoxy-4-vinylphenol/vanillin/guaiacol combination. RE had rich bioactive compounds related to α-glucosidase, α-amylase and tyrosinase inhibitory activity. Volatile compounds, including 2-methoxy-4-vinylphenol, vanillin and guaiacol, enhanced the inhibitory activity of RE against α-glucosidase, α-amylase and tyrosinase activities.

Inhibitory effect of IQ-1S, a selective c-Jun N-terminal kinase (JNK) inhibitor, on phenotypical and cytokine-producing characteristics in human macrophages and T-cells

c-Jun N-terminal kinase (JNK) is a critical mitogen activated protein kinase (MAPK) implicated in inflammatory processes, with IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt) being a high-affinity JNK inhibitor with pronounced anti-inflammatory properties. Here, we studied direct effects of IQ-1S on phenotypical and cytokine-producing characteristics of activated human monocytes/macrophages and T cells in vitro. Purified monocyte/macrophage cells were activated by bacterial lipopolysaccharide (LPS, 1 μg/ml) for 24 h, while T cells were activated by particles conjugated with antibodies (Abs) against human CD2, CD3, and CD28 for 48 h. Treatment with IQ-1S (0.5-25 μМ) in the presence of LPS reduced percentages of CD197 (CCR7)-positive cells in macrophage cultures, without affecting CD16⁺ (FcγRIII, low-affinity Fc-receptor), CD119⁺ (interferon-γ receptor 1), and CD124⁺ (IL-4 receptor α-subunit) cells. In addition, IQ-1S reduced production of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-10 in macrophage cultures. In activated T cell cultures, IQ-1S decreased CD25⁺ cell numbers in both CD4-positive and CD4-negative T cell compartments. Central memory СD45RA^-/СD197⁺ and effector memory СD45RA^-/СD197^- T cells were more sensitive to IQ-1S-mediated suppression, as compared to naïve СD45RA⁺/СD197⁺ and terminally-differentiated effector СD45RA⁺/СD197^- T cells. IQ-1S also suppressed T-cell cytokine production (IL-2, interferon-ɣ, IL-4, and IL-10). Collectively, the results suggest that both human macrophage and T cells could be immediate cell targets for IQ-1S-based anti-inflammatory immunotherapy. IQ-1S-mediated suppressive effects were unlikely to be associated with macrophage/T helper polariation.

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.

An expedient synthesis of novel spiro[indenoquinoxaline-pyrrolizidine]-pyrazole conjugates with anticancer activity from 1,5-diarylpent-4-ene-1,3-diones through the 1,3-dipolar cycloaddition/cyclocondensation sequence

A highly regio- and stereoselective two-stage route for the synthesis of spiro[indenoquinoxaline-pyrrolizidine]-pyrazole hybrids with anticancer activity has been developed.

Design, synthesis, in silico docking studies and biological evaluation of novel quinoxaline-hydrazide hydrazone-1,2,3-triazole hybrids as α-glucosidase inhibitors and antioxidants

Novel quinoxaline-hydrazidehydrazone-1,2,3-triazole hybrids were synthesized, characterized and screened for α-glucosidase inhibitory and antioxidant activities.

Novel oxazolxanthone derivatives as a new type of α-glucosidase inhibitor: synthesis, activities, inhibitory modes and synergetic effect

Xanthone derivatives have shown good α-glucosidase inhibitory activity and have drawn increased attention as potential anti-diabetic compounds. In this study, a series of novel oxazolxanthones were designed, synthesized, and investigated as α-glucosidase inhibitors. Inhibition assays indicated that compounds 4-21 bearing oxazole rings exhibited up to 30-fold greater inhibitory activity compared to their corresponding parent compound 1b. Among them, compounds 5-21 (IC₅₀ = 6.3 ± 0.4-38.5 ± 4.6 μM) were more active than 1-deoxynojirimycin (IC₅₀ = 60.2 ± 6.2 μM), a well-known α-glucosidase inhibitor. In addition, the kinetics of enzyme inhibition measured by using Lineweaver-Burk analysis shows that compound 4 is a competitive inhibitor, while compounds 15, 16 and 20 are non-competitive inhibitors. Molecular docking studies showed that compound 4 bound to the active site pocket of the enzyme while compounds 15, 16, and 20 did not. More interestingly, docking simulations reveal that some of the oxazolxanthone derivatives bind to different sites in the enzyme. This prediction was further confirmed by the synergetic inhibition experiment, and the combination of representative compounds 16 and 20 at the optimal ratio of 4:6 led to an IC₅₀ value of 1.9 ± 0.7 μM, better than the IC₅₀ value of 7.1 ± 0.9 μM for compound 16 and 8.6 ± 0.9 μM for compound 20.

A facile atom economic one pot multicomponent synthesis of bioactive spiro-indenoquinoxaline pyrrolizines as potent antioxidants and anti-cancer agents

One pot method for the synthesis of biologically active novel spiro-indenoquinoxaline pyrrolizines by means of four-component reaction between ninhydrin, o-phenylenediamine, l-proline and quinolinyl chalcones in methanol via [3+2] cycloaddition.

Anti-Inflammatory Effects and Joint Protection in Collagen-Induced Arthritis after Treatment with IQ-1S, a Selective c-Jun N-Terminal Kinase Inhibitor

c-Jun N-terminal kinases (JNKs) participate in many physiologic and pathologic processes, including inflammatory diseases. We recently synthesized the sodium salt of IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime) and demonstrated that it is a high-affinity JNK inhibitor and inhibits murine delayed-type hypersensitivity. Here we show that IQ-1S is highly specific for JNK and that its neutral form is the most abundant species at physiologic pH. Molecular docking of the IQ-1S syn isomer into the JNK1 binding site gave the best pose, which corresponded to the position of cocrystallized JNK inhibitor SP600125 (1,9-pyrazoloanthrone). Evaluation of the therapeutic potential of IQ-1S showed that it inhibited matrix metalloproteinase 1 and 3 gene expression induced by interleukin-1β in human fibroblast-like synoviocytes and significantly attenuated development of murine collagen-induced arthritis (CIA). Treatment with IQ-1S either before or after induction of CIA resulted in decreased clinical scores, and joint sections from IQ-1S-treated CIA mice exhibited only mild signs of inflammation and minimal cartilage loss compared with those from control mice. Collagen II-specific antibody responses were also reduced by IQ-1S treatment. By contrast, the inactive ketone derivative 11H-indeno[1,2-b]quinoxalin-11-one had no effect on CIA clinical scores or collagen II-specific antibody titers. IQ-1S treatment also suppressed proinflammatory cytokine and chemokine levels in joints and lymph node cells. Finally, treatment with IQ-1S increased the number of Foxp3(+)CD4(+)CD25(+) regulatory T cells in lymph nodes. Thus, IQ-1S can reduce inflammation and cartilage loss associated with CIA and can serve as a small-molecule modulator for mechanistic studies of JNK function in rheumatoid arthritis.