Design,synthesis and biological evaluation of novel coumarin thiazole derivatives as α-glucosidase inhibitors

A new series of coumarin thiazole derivatives 7a-7t were synthesized, characterized by ¹H NMR, ¹³C NMR and element analysis, evaluated for their α-glucosidase inhibitory activity. The majority of the screened compounds displayed potent inhibitory activities with IC₅₀ values in the range of 6.24 ± 0.07–81.69 ± 0.39 μM, when compared to the standard acarbose (IC₅₀ = 43.26 ± 0.19 μM). Structure–activity relationship (SAR) studies suggest that the pattern of substitution in the phenyl ring is closely related to the biological activity of this class of compounds. Among all the tested molecules, compound 7e (IC₅₀ = 6.24 ± 0.07 μM) was found to be the most active compound in the library of coumarin thiazole derivatives. Enzyme kinetic studies showed that compound 7e is a non-competitive inhibitor with a K_i of 6.86 μM. Furthermore, the binding interactions of compound 7e with the active site of α-glucosidase were confirmed through molecular docking. This study has identified a new class of potent α-glucosidase inhibitors for further investigation.     

Synthesis,biological evaluation,and docking studies of novel 5,6-diaryl-1,2,4-triazine thiazole derivatives as a new class of α-glucosidase inhibitors

A novel 5,6-diaryl-1,2,4-triazine thiazole derivatives (7a-7q) were synthesized and characterized by ¹H NMR and ¹³C NMR and evaluated for their α-glucosidase inhibitory activity. All tested compounds displayed good α-glucosidase inhibitory activity with IC₅₀ values ranging between 2.85 ± 0.13 and 14.19 ± 0.23 μM when compared to the standard drug acarbose (IC₅₀ = 817.38 ± 6.27 μM). Compound 7i (IC₅₀ = 2.85 ± 0.13 μM) exhibited the highest activity among this series of compounds. Molecular docking studies were carried out in order to investigate the binding mode of this class of compounds to α-glucosidase. This study showed that these 5,6-diaryl-1,2,4-triazine thiazole derivatives are a new class of α-glucosidase inhibitors.     

Design,synthesis and biological evaluation of novel dual inhibitors of acetylcholinesterase and β-secretase

To explore novel effective drugs for the treatment of Alzheimer’s disease (AD), a series of dual inhibitors of acetylcholineterase (AChE) and β-secretase (BACE-1) were designed based on the multi-target-directed ligands strategy. Among them, inhibitor 28 exhibited good dual potency in enzyme inhibitory potency assay (BACE-1: IC₅₀ = 0.567 μM; AChE: IC₅₀ = 1.83 μM), and also showed excellent inhibitory effects on Aβ production of APP transfected HEK293 cells (IC₅₀ = 98.7 nM) and mild protective effect against hydrogen peroxide (H₂O₂)-induced PC12 cell injury. Encouragingly, intracerebroventricular injection of 28 into amyloid precursor protein (APP) transgenic mice caused a 29% reduction of Aβ_1–40 production. Therefore, 28 was demonstrated as a good lead compound for the further study and more importantly, the strategy of AChE and BACE-1 dual inhibitors might be a promising direction for developing novel drugs for AD patients.     

Design,synthesis, and biological evaluation of novel selective peptide inhibitors of 11β-hydroxysteroid dehydrogenase 1

The enzyme 11β-HSD1 plays a crucial role in the tissue-specific regulation of cortisol levels and it has been associated with various diseases. Inhibition of 11β-HSD1 is an attractive intervention strategy and the discovery of novel selective 11β-HSD1 inhibitors is of high relevance. In this study, we identified and evaluated a new series of selective peptide 11β-HSD1 inhibitors with potential for skin care applications. This novel scaffold was designed with the aid of molecular modeling and two previously reported inhibitors. SAR optimization yielded highly active peptides (IC₅₀ below 400?nM) that were inactive at 1?µM concentration against structurally related enzymes (11β-HSD2, 17β-HSD1 and 17β-HSD2). The best performing peptides inhibited the conversion of cortisone into cortisol in primary human keratinocytes and the most active compound, 5d, was further shown to reverse cortisone-induced collagen damage in human ex-vivo tissue.     

Design,synthesis and biological evaluation of novel hybrids of N-aryl pyrrothine-base α-pyrone as bacterial RNA polymerase inhibitors

Antibiotic resistance in bacteria has been an emerging public health problem, thus discovery of novel and effective antibiotics is urgent. A series of novel hybrids of N-aryl pyrrothine-base α-pyrone hybrids was designed, synthesized and evaluated as bacterial RNA polymerase (RNAP) inhibitors. Among them, compound 13c exhibited potent antibacterial activity against antibiotic-resistant S. aureus with the minimum inhibitory concentration (MIC) in the range of 1–4 μg/mL. Moreover, compound 13c exhibited strong inhibitory activity against E.coli RNAP with IC₅₀ value of 16.06 μM, and cytotoxicity in HepG2 cells with IC₅₀ value of 7.04 μM. The molecular docking study further suggested that compound 13c binds to the switch region of bacterial RNAP. In summary, compound 13c is a novel bacterial RNAP inhibitor, and a promising lead compound for further optimization.     

Molecular docking studies and synthesis of novel bisbenzimidazole derivatives as inhibitors of α-glucosidase

A series of bisbenzimidazole derivatives starting from o-phenylenediamine and 4-nitro-o-phenylenediamine were prepared with oxalic acid. Most of the reactions were conducted using both the microwave and conventional methods to compare yields and reaction times. The operational simplicity, environmental friendly conditions and high yield in a significantly short reaction time were the major benefits. All substances’ inhibitory activities against α-glucosidase were evaluated. The results may suggest a significant role for the nature of bisbenzimidazole compounds in their inhibitory action against α-glucosidase. They showed different range of α-glucosidase inhibitory potential with IC₅₀ value ranging between 0.44 ± 0.04 and 6.69 ± 0.01 μM when compared to the standard acarbose (IC₅₀, 13.34 ± 1.26 μM). This has described a new class of α-glucosidase inhibitors. Molecular docking studies were done for all compounds to identify important binding modes responsible for inhibition activity of α-glucosidase.     

Synthesis,biological evaluation and molecular docking studies of chromone hydrazone derivatives as α-glucosidase inhibitors

A series of chromone hydrazone derivatives 4a–4p have been synthesized, characterized by ¹H NMR and ¹³C NMR and evaluated for their in vitro α-glucosidase inhibitory activity. Out of these tested compounds, six (4a, 4b, 4d, 4j, 4o and 4p) displayed potent α-glucosidase inhibitory activity with IC₅₀ values in the range of 20.1 ± 0.19 μM to 45.7 ± 0.23 μM, as compared to the standard drug acarbose (IC₅₀ = 817.38 ± 6.27 μM). Among this series, compound 4d (IC₅₀ = 20.1 ± 0.19 μM) with 4-sulfonamide substitution at phenyl part of hydrazide was found to be the most active compound. Lineweaver-Burk plot analysis indicated that compound 4d is a non-competitive inhibitor of α-glucosidase. The binding interactions of the most active analogs were confirmed through molecular docking studies. Docking studies showed 4d are interacting with the residues Glu-276, Asp-214, Asp-349 and Arg-439 through hydrogen bonds, arene-anion and arene-cation interactions. In summary, our studies shown that these chromone hydrazone derivatives are a new class of α-glucosidase inhibitors.     

Design,synthesis, and biological evaluation of novel quinoline derivatives as HIV-1 Tat–TAR interaction inhibitors

Thirty-two quinoline derivatives were designed and synthesized as HIV-1 Tat–TAR interaction inhibitors. All the compounds showed high antiviral activities in inhibiting the formation of SIV-induced syncytium in CEM174 cells. Nine of them with low cytotoxicities were evaluated by Tat dependent HIV-1 LTR-driven CAT gene expression colorimetric enzyme assay in human 293T cells, indicating effective inhibitory activities of blocking the Tat–TAR interaction. Molecular modeling experiments indicated that these compounds may inhibit Tat–TAR interaction by binding to Tat protein instead of TAR RNA.     

Design, synthesis and biological evaluation of β-carboline derivatives as novel inhibitors targeting B-Raf kinase

β-Carboline family of compounds is a large group of alkaloids widely distributed in nature and exhibits broad-spectrum anti-tumor activities. We designed and synthesized two series of novel 1-carboxamide- and 6-sulfonamide-substituted β-carboline derivatives 7a-p and 12a-b, and their wild type B-Raf kinase inhibitory activities were described. Most compounds showed moderate to excellent inhibitory activities. Among them, 1-carboxamide-6-(N-(3-(dimethylamino)propyl)-sulfamoyl)-β-carboline, 7e exhibited potent activity (IC(50)=1.62 μM), showing the potential for further investigation as a lead compound.     

Design, synthesis and biological evaluation of novel imidazopyridines as potential antidiabetic GSK3β inhibitors

Design, synthesis and biological evaluation of the imidazopyridine analogs as novel GSK3β inhibitors for treatment of type 2 diabetes mellitus are described. Most of the analogs exhibited excellent inhibitory activities (IC50<44 nM) against glycogen synthase kinase 3β (GSK3β). The structure-activity relationship (SAR) of the imidazopyridine analogs and the binding mode of analog 23 in the catalytic domain of GSK3β, based on our X-ray crystallography study, are described. In particular, analog 28, which was selected as a potential drug candidate for treatment of type 2 diabetes mellitus, exhibited excellent GSK3β inhibition, pharmacokinetic profiles and blood glucose lowering effect in mouse.     

A concise synthesis and evaluation of new malonamide derivatives as potential α-glucosidase inhibitors

A series of new malonamide derivatives were synthesized by Michael addition reaction of N¹,N³-di(pyridin-2-yl)malonamide into α,β-unsaturated ketones mediated by DBU in DCM at ambient temperature. The inhibitory potential of these compounds in vitro, against α-glucosidase enzyme was evaluated. Result showed that most of malonamide derivatives were identified as a potent inhibitors of α-glucosidase enzyme. Among all the compounds, 4K (IC₅₀ = 11.7 ± 0.5 μM) was found out as the most active one compared to standard drug acarbose (IC₅₀ = 840 ± 1.73 μM). Further cytotoxicity of 4a–4m were also evaluated against a number of cancer and normal cell lines and interesting results were obtained.     

Ultrasonic synthesis of tyramine derivatives as novel inhibitors of α-glucosidase in vitro

Tyramine derivatives 3–27 were synthesized by using conventional and environmental friendly ultrasonic techniques. These derivatives were then evaluated for the first time for their α-glucosidase (Sources: Saccharomyces cerevisiae and mammalian rat-intestinal acetone powder) inhibitory activity by using in vitro mechanism-based biochemical assays. Compounds 7, 14, 20, 21 and 26 were found to be more active (IC₅₀?=?49.7?±?0.4, 318.8?±?3.7, 23.5?±?0.9, 302.0?±?7.3 and 230.7?±?4.0?μM, respectively) than the standard drug, acarbose (IC₅₀?=?840.0?±?1.73?μM (observed) and 780?±?0.028?μM (reported)) against α-glucosidase obtained from Saccharomyces cerevisiae. Kinetic studies were carried out on the most active members of the series in order to determine their mode of inhibition and dissociation constants. Compounds 7, 20 and 26 were found to be the competitive inhibitors of α-glucosidase. These compounds were also screened for their protein antiglycation, and dipeptidyl peptidase-IV (DPP-IV) inhibitory activities. Only compounds 20, 22 and 27 showed weak antiglycation activity with IC₅₀ values 505.27?±?5.95, 581.87?±?5.50 and 440.58?±?2.74?μM, respectively. All the compounds were found to be inactive against DDP-IV enzyme. Inhibition of α-glucosidase, DPP-IV enzymes and glycation of proteins are valid targets for the discovery of antidiabetic drugs. Cytotoxicity of compounds 3–27 was also evaluated by using mouse fibroblast 3T3 cell lines. All the compounds were found to be noncytotoxic. The current study describes the synthesis α-glucosidase inhibitory activity of derivatives, based on a natural product tyramine template. The compounds reported here may serve as the starting point for the design and development of novel α-glucosidase inhibitors as antidiabetic agents.     

Design,synthesis and biological evaluation of mogrol derivatives as a novel class of AMPKα2β1γ1 activators

Adenosine monophosphate-activated protein kinase (AMPK) has been considered as a promising drug target for its regulation in both glucose and lipid metabolism. Mogrol was originally identified from high throughput screening as a small molecule activator of AMPK subtype α2β1γ1. In order to enhance its potency on AMPK and summarize the structure-activity relationships, a series of mogrol derivatives were designed, synthesized and evaluated in pharmacological AMPK activation assays. The results showed that the amine derivatives at the 24-position can improve the potency. Among them, compounds 3 and 4 exhibited the best potency (EC₅₀: 0.15 and 0.14 μM) which was 20 times more potent than mogrol (EC₅₀: 3.0 μM).     

Design,synthesis and α-glucosidase inhibition study of novel embelin derivatives

Abstract

Embelin is a naturally occurring para-benzoquinone isolated from Embelia ribes (Burm. f.) of the Myrsinaceae family. It was first discovered to have potent inhibitory activity (IC₅₀ = 4.2?μM) against α-glucosidase in this study. Then, four series of novel embelin derivatives were designed, prepared and evaluated in α-glucosidase inhibition assays. The results show that most of the embelin derivatives synthesised are effective α-glucosidase inhibitors, with IC₅₀ values at the micromolar level, especially 10d, 12d, and 15d, the IC₅₀ values of which are 1.8, 3.3, and 3.6?μM, respectively. Structure–activity relationship (SAR) studies suggest that hydroxyl groups in the 2/5-position of para-benzoquinone are very important, and long-chain substituents in the 3-position are highly preferred. Moreover, the inhibition mechanism and kinetics studies reveal that all of 10d, 12d, 15d, and embelin are reversible and mixed-type inhibitors. Furthermore, docking experiments were carried out to study the interactions between 10d and 15d with α-glucosidase.     

Symmetrical α-bromoacryloylamido diaryldienone derivatives as a novel series of antiproliferative agents. Design,synthesis and biological evaluation

In a continuing study of hybrid compounds containing the α-bromoacryloyl moiety as potential anticancer drugs, we synthesized a novel series of hybrids 4a–h, in which this moiety was linked to a 1,5-diaryl-1,4-pentadien-3-one system. Many of the conjugates prepared (4b, 4c, 4e and 4g) demonstrated pronounced, submicromolar antiproliferative activity against four cancer cell lines. Moreover, compound 4b induced apoptosis through the mitochondrial pathway and activated caspase-3 in a concentration-dependent manner.     

Structure-based design, synthesis, and biological evaluation of dihydroquinazoline-derived potent β-secretase inhibitors

Structure-based design, synthesis, and biological evaluation of a series of dihydroquinazoline-derived β-secretase inhibitors incorporating thiazole and pyrazole-derived P2-ligands are described. We have identified inhibitor 4f which has shown potent enzyme inhibitory (K(i)=13nM) and cellular (IC(50)=21nM in neuroblastoma cells) assays. A model of 4f was created based upon the X-ray structure of 3a-bound β-secretase. The model suggested possible interactions in the active site.     

Design, synthesis, and evaluation of a novel class of 2,3-disubstituted-tetrahydro-β-carboline derivatives

Several novel tetrahydro-β-carboline derivatives with amino acid residues at the 2-position and a glucosamine group at the 3-position of the tetrahydro-β-carboline nucleus were synthesized from a readily available starting material, tryptophane, and were evaluated for their anti-inflammatory activity in the present study. Our results showed that all of the derivatives tested exhibited a significant inhibition of xylene-induced inflammation in mice.     

Design,synthesis and biological evaluation of metronidazole–thiazole derivatives as antibacterial inhibitors

A series of metronidazole–thiazole derivatives has been designed, synthesized and evaluated as potential antibacterial inhibitors. All the synthesized compounds were determined by elemental analysis, ¹H NMR and MS. They were also tested for antibacterial activity against Escherichia coli, Bacillus thuringiensis, Bacillus subtilis and Pseudomonas aeruginosa as well as for the inhibition to FabH. The results showed that compound 5e exhibited the most potent inhibitory activity against E. coli FabH with IC₅₀ of 4.9 μM. Molecular modeling simulation studies were performed in order to predict the biological activity of proposed compounds. Toxicity assay of compounds 5a, 5b, 5d, 5e, 5g and 5i showed that they were noncytotoxic against human macrophage. The results revealed that these compounds offered remarkable viability.     

The synthesis and SAR of novel diarylsulfone 11β-HSD1 inhibitors

In this communication, human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitory activities of a novel series of diarylsulfones are described. Optimization of this series resulted in several highly potent 11β-HSD1 inhibitors with excellent pharmacokinetic (PK) properties. Compound (S)-25 showed excellent efficacy in a non-human primate ex vivo pharmacodynamic model.     

The synthesis and evaluation of indolylureas as PKCα inhibitors

PKCα and PKA have crucial but opposing roles in the regulation of calcium handling within myocytes. Identification of compounds that inhibit PKCα, but not PKA, are potential therapeutic targets for the treatment of heart disease. The synthesis of indolylureas are described, and a compound displaying nanomolar inhibition towards PKCα with significant selectivity over PKA has been identified.