Discovery of phenyl acetamides as potent and selective GPR119 agonists

The paper describes the SAR/SPR studies that led to the discovery of phenoxy cyclopropyl phenyl acetamide derivatives as potent and selective GPR119 agonists. Based on a cis cyclopropane scaffold discovered previously, phenyl acetamides such as compound 17 were found to have excellent GPR119 potency and improved physicochemical properties. Pharmacokinetic data of compound 17 in rat, dog and rhesus will be described. Compound 17 was suitable for QD dosing based on its predicted human half-life, and its projected human dose was much lower than that of the recently reported structurally-related benzyloxy compound 2. Compound 17 was selected as a tool compound candidate for NHP (Non-Human Primate) efficacy studies.     

Discovery and optimization of 1,7-disubstituted-2,2-dimethyl-2,3-dihydroquinazolin-4(1H)-ones as potent and selective PKCθ inhibitors

A high-throughput screening campaign helped us to identify an initial lead compound (1) as a protein kinase C-θ (PKCθ) inhibitor. Using the docking model of compound 1 bound to PKCθ as a model, structure-based drug design was employed and two regions were identified that could be explored for further optimization, i.e., (a) a hydrophilic region around Thr442, unique to PKC family, in the inner part of the hinge region, and (b) a lipophilic region at the forefront of the ethyl moiety. Optimization of the hinge binder led us to find 1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one as a potent and selective hinge binder, which resulted in the discovery of compound 5. Filling the lipophilic region with a suitable lipophilic substituent boosted PKCθ inhibitory activity and led to the identification of compound 10. The co-crystal structure of compound 10 bound to PKCθ confirmed that both the hydrophilic and lipophilic regions were fully utilized. Further optimization of compound 10 led us to compound 14, which demonstrated an improved pharmacokinetic profile and inhibition of IL-2 production in a mouse.     

A new phenolic acid from Zanthoxylum nitidum var. tomentosum (Rutaceae) and its chemotaxonomic significance

A new compound, nitomentosin (1), along with sixteen known compounds (2–17), were isolated from Zanthoxylum nitidum var. tomentosum (Rutaceae). The structure of compound 1 including absolute configurations was determined by detailed spectroscopic information (HRESIMS and NMR) and from the electronic circular dichroism (ECD) spectra. From the present investigation, compound 3 is a new natural compound although it has been reported previously as a synthetic substance, and compound 15 is found for the first time in a plant. All these compounds except 2, 5–10 and 12 were isolated from Z. nitidum for the first time. Furthermore, the chemotaxonomic significance of the isolated compounds is discussed.     

Inhibitory effects of novel synthetic methimazole derivatives on mushroom tyrosinase and melanogenesis

In this study, we synthesized 4 methimazole (2-mercapto-1-methylimidazole, MMI) derivatives. The kinetics of inhibition on mushroom tyrosinase by methimazole and its derivatives were investigated. The results indicated that tert-butyl 3-methyl-2-sulfanylidene-2,3-dihydro-1H-imidazole-1-carboxylate (compound 3; 3), 2-mercaptoimidazole (MI; compound 1; 1) and MMI (compound 2; 2) significantly inhibited tyrosinase activity in a dose-dependent manner, exhibiting an IC₅₀ value of 1.50 mM, 4.11 mM, and 1.43 mM. However, compound 4 (4), compound 5 (5), and compound 6 (6) exerted no inhibitory effect on mushroom tyrosinase activity. Kinetic analysis indicated that 3 was a noncompetitive tyrosinase inhibitor, whereas both 1 and 2 were exhibited as mixed-type tyrosinase inhibitors. Furthermore, 3 exerted a potent inhibitory effect on intracellular melanin formation in the B16/F10 murine melanoma cells and did not cause cytotoxicity, as 1 and 2 did.     

Structure-based design,synthesis, and binding mode analysis of novel and potent chymase inhibitors

Based on insight from the X-ray crystal structure of human chymase in complex with compound 1, a lactam carbonyl of the diazepane core was exchanged with O-substituted oxyimino group, leading to amidoxime derivatives. This modification resulted in highly potent chymase inhibitors, such as O-phenylamidoxime 5f. X-ray crystal structure analysis indicated that compound 5f induced movement of the Leu99 and Tyr94 side chains at the S2 site, and the increase in inhibitory activity of O-phenyl amidoxime derivatives suggested that the O-phenyl moiety interacted with the Tyr94 residue. Surface plasmon resonance experiments showed that compound 5f had slower association and dissociation kinetics and the calculated residence time of compound 5f to human chymase was extended compared to that of amide compound 1.     

Benzoxazine derivatives of phytophenols show anti-plasmodial activity via sodium homeostasis disruption

Development of new class of anti-malarial drugs is an essential requirement for the elimination of malaria. Bioactive components present in medicinal plants and their chemically modified derivatives could be a way forward towards the discovery of effective anti-malarial drugs. Herein, we describe a new class of compounds, 1,3-benzoxazine derivatives of pharmacologically active phytophenols eugenol (compound 3) and isoeugenol (compound 4) synthesised on the principles of green chemistry, as anti-malarials. Compound 4, showed highest anti-malarial activity with no cytotoxicity towards mammalian cells. Compound 4 induced alterations in the intracellular Na⁺ levels and mitochondrial depolarisation in intraerythrocytic Plasmodium falciparum leading to cell death. Knowing P-type cation ATPase PfATP4 is a regulator for sodium homeostasis, binding of compound 3, compound 4 and eugenol to PfATP4 was analysed by molecular docking studies. Compounds showed binding to the catalytic pocket of PfATP4, however compound 4 showed stronger binding due to the presence of propylene functionality, which corroborates its higher anti-malarial activity. Furthermore, anti-malarial half maximal effective concentration of compound 4 was reduced to 490?nM from 17.54?µM with nanomaterial graphene oxide. Altogether, this study presents anti-plasmodial potential of benzoxazine derivatives of phytophenols and establishes disruption of parasite sodium homeostasis as their mechanism of action.     

A CD4 mimic as an HIV entry inhibitor: Pharmacokinetics

To date, several small molecules of CD4 mimics, which can suppress competitively the interaction between an HIV-1 envelope glycoprotein gp120 and a cellular surface protein CD4, have been reported as viral entry inhibitors. A lead compound 2 (YYA-021) with relatively high potency and low cytotoxicity has been identified previously by SAR studies. In the present study, the pharmacokinetics of the intravenous administration of compound 2 in rats and rhesus macaques is reported. The half-lives of compound 2 in blood in rats and rhesus macaques suggest that compound 2 shows wide tissue distribution and relatively high distribution volumes. A few hours after the injection, both plasma concentrations of compound 2 maintained micromolar levels, indicating it might have promise for intravenous administration when used combinatorially with anti-gp120 monoclonal antibodies.     

Structure-based design of 3-aryl-6-amino-triazolo[4,3-b]pyridazine inhibitors of Pim-1 kinase

A series of substituted 3-aryl-6-amino-triazolo[4,3-b]pyridazines were identified as highly selective inhibitors of Pim-1 kinase. Initial exploration identified compound 24 as a potent, selective inhibitor, limited in its utility by poor solubility and permeability. Understanding the unusual ATP-binding site of the Pim kinases and X-ray crystallographic data on compound 24 led to design improvements in this class of inhibitor. This resulted in compound 29, a selective, soluble and permeable inhibitor of Pim-1.     

Computational discovery and biological evaluation of novel inhibitors targeting histone-lysine N-methyltransferase SET7

Histone-lysine N-methyltransferase SET7 emerged as a potential target for multiple cancers. In a virtual screening program used to explore new and potent inhibitors of SET7, compound 16 was discovered as a top hit with an IC₅₀ value of 6.02 μM. A further similarity search afforded a new compound 23, which exhibited better activity against SET7 with an IC₅₀ value of 1.96 μM. Importantly, compound 23 selectively inhibited the proliferation of MV4-11 cells. Comprehensively, compound 23 can serve as a lead for further identification and development of more potent SET7 inhibitors.     

5-(4-Hydroxyphenyl)-3H-1,2-dithiole-3-thione-based fibrates as potential hypolipidemic and hepatoprotective agents

Hypolipidemic effects of the newly synthesized 5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione-based fibrates were evaluated in Triton WR-1339 and high-fat diet (HFD)-induced hyperlipidemic mice. Preliminary screening of all the synthesized compounds was done by using an acute model (Triton WR-1339 model), in which compound 6 shown more significant antidyslipidemic activity than fenofibrate (FF). The compound 6 was also found to reduce serum triglyceride (TG), total cholesterol (TC) and low density lipoprotein cholesterin (LDL) in HFD-induced hyperlipidemic mice. Moreover, compound 6 displayed hepatoprotective effect, a significant amelioration in hepatic indices (AST and ALT) toxicity was observed and the histological examination showed that compound 6 inhibited the development of hepatic lipid accumulation and ameliorated the damage in hepatic tissue compared to model mice. Additional effects such as the potent antioxidant and anti-inflammatory action confirmed and reinforced the efficacy of compound 6 as a new agent of dual-effect hypolipidemic and hepatoprotective activities.     

Immunomodulation-mediated anticancer activity of a novel compound from Brugmansia suaveolens leaves

Immunomodulation activity-guided fractionation of ethanol extract of Brugmansia suaveolens leaves was carried out to isolate a novel compound SUPH036-022A (1) by co-culturing the test fraction/compound activated PBMC with MCF7 and A549 cancer cell lines. Assessment of immune markers in PBMC, and analysis of apoptosis markers and cell cycle was carried out for cancer cells. The structure of the isolated compound was elucidated by spectral analysis. Compound 1 enhanced the secretion of immune markers, IL-2 and IFN-γ, from PBMC. Further, compound 1 treated PBMC increased cell death in MCF7 and A549 cell lines and induced ROS production and mitochondrial membrane perturbation, leading to apoptosis. Flow cytometry analysis revealed; compound 1 stimulated PBMC to cause a five-fold increase in cell cycle perturbations in the sub-G1 stage of cancer cells as compared to the negative control. The compound, in the absence of PBMC, only had a weak cytotoxic activity against these cell lines. Thus, compound 1 is a novel lead for immunomodulation-mediated anticancer activity.     

Discovery of 3-(4-bromophenyl)-6-nitrobenzo[1.3.2]dithiazolium ylide 1,1-dioxide as a novel dual cyclooxygenase/5-lipoxygenase inhibitor that also inhibits tumor necrosis factor-α production

In the present study we have discovered compound 1, a benzo[1.3.2]dithiazolium ylide-based compound, as a new prototype dual inhibitor of cyclooxygenase (COX) and 5-lipoxygenase (5-LOX). Compound 1 was initially discovered as a COX-2 inhibitor, resulting indirectly from the COX-2 structure-based virtual screening that identified compound 2 as a virtual hit. Compounds 1 and 2 inhibited COX-1 and COX-2 in mouse macrophages with IC₅₀ in the range of 1.5–18.1 μM. Both compounds 1 and 2 were also found to be potent inhibitors of human 5-LOX (IC₅₀ = 1.22 and 0.47 μM, respectively). Interestingly, compound 1 also had an inhibitory effect on tumor necrosis factor-α (TNF-α) production (IC₅₀ = 0.44 μM), which was not observed with compound 2. Docking studies suggested the (S)-enantiomer of 1 as the biologically active isomer that binds to COX-2. Being a cytokine-suppressive dual COX/5-LOX inhibitor, compound 1 may represent a useful lead structure for the development of advantageous new anti-inflammatory agents.     

New benzyl pyridinium derivatives bearing 2,4-dioxochroman moiety as potent agents for treatment of Alzheimer’s disease: Design,synthesis, biological evaluation,and docking study

A new series of benzyl pyridinium-2,4-dioxochroman derivatives 7a-o was synthesized and evaluated as new anti-Alzheimer agents. Among the synthesized compounds, the compounds 7f and 7i exhibited the most potent anti-AChE and anti-BuChE activities, respectively. The kinetic study of the compound 7f revealed that this compound inhibited AChE in a mixed-type inhibition mode. Furthermore, the docking study of the compounds 7f and 7i showed that these compounds bound to both the catalytic site (CS) and peripheral anionic site (PAS) of AChE and BuChE, respectively. The compound 7f also exhibited a greater self-induced Aβ peptide aggregation inhibitory activity in compare to donepezil. Furthermore, the neuroprotective activity of this compound at 20 μM was comparable to that of the standard neuroprotective agent (quercetin).     

Design,synthesis, and evaluation of novel porcupine inhibitors featuring a fused 3-ring system based on the ‘reversed’ amide scaffold

The Wnt signaling pathway is an essential signal transduction pathway which leads to the regulation of cellular processes such as proliferation, differentiation and migration. Aberrant Wnt signaling is known to have an association with multiple cancers. Porcupine is an enzyme that catalyses the addition of palmitoleate to a serine residue in Wnt proteins, a process which is required for the secretion of Wnt proteins. Here we report the synthesis and structure–activity-relationship of the novel porcupine inhibitors based on a ‘reversed’ amide scaffold. The leading compound 53 was as potent as the clinical compound LGK974 in a cell based STF reporter gene assay. Compound 53 potently inhibited the secretion of Wnt3A, therefore was confirmed to be a porcupine inhibitor. Furthermore, compound 53 showed excellent chemical and plasma stabilities. However, the clearance of compound 53 in liver microsomal tests was moderate to high, and the solubility of compound 53 was suboptimal. Collective efforts toward further optimization of this novel tricyclic template to develop better porcupine inhibitors will be subsequently undertaken and reported in due course.     

A natural phenylpropionate derivative from Mirabilis himalaica inhibits cell proliferation and induces apoptosis in HepG2 cells

Bioactivity-guided study led to the isolation of a natural phenylpropionate derivative, (E)-3-(4-hydroxy-2-methoxyphenyl)-propenoic acid 4-hydroxy-3-methoxyphenyl ester from the roots of Mirabilis himalaica. Cellular analysis showed that compound 1 specifically inhibited the cancer cell growth through the S phase arrest. Mechanistically, compound 1 was able to induce the apoptosis in HepG2 cells through mitochondrial apoptosis pathway in which Bcl-2 and p53 were required. Interestingly, the cellular phenotype of compound 1 were shown specifically in cancer cells originated from hepatocellular carcinoma (HepG2) while compromised influence by compound 1 were detected within the normal human liver cells (L-02). Consistently, the in vivo inhibitory effects of compound 1 on tumor growth were validated by the in xenograft administrated with HepG2 cells. Our results provided a novel compound which might serve as a promising candidate and shed light on the therapy of the hepatocellular carcinoma.     

Discovery of tranylcypromine analogs with an acylhydrazone substituent as LSD1 inactivators: Design,synthesis and their biological evaluation

Lysine specific demethylase 1 (LSD1), the first identified histone demethylase, plays an important role in epigenetic regulation of gene activation and repression, has been reported to be up-regulated and involved in numbers of solid malignant tumors. In this study, we identified a series of phenylalanyl hydrazones based LSD1 inhibitors, and the most potent one, compound 4q, can inactivate LSD1 with IC₅₀?=?91.83?nM. In cellular level, compound 4q can induce the accumulation of CD86 as well as H3K4me2, and inhibit gastric cancer cell proliferation by inactivating LSD1. Our findings indicated that compound 4q may serve as a potential leading compound to target LSD1 overexpressed gastric cancer.     

Anti-cancer activity of m-carborane-containing trimethoxyphenyl derivatives through tubulin polymerization inhibition

m-Carborane-containing compound 1a was identified as a cell growth inhibitor from a random screening of a boron compound library. As 1a is a mixture of diastereomers due to the presence of two chiral carbons, we designed achiral derivatives 2–4 and studied the structure-activity relationships of the methoxy groups on the benzene ring. 3,4,5-Trimethoxybenzyl derivative 2a and 3,4,5-trimethoxybenzoyl derivative 3a showed more potent anti-cancer activity against the human breast cancer cell line MDA-MB-453 than lead compound 1a. Compound 3a inhibited tubulin polymerization in a dose-dependent manner.     

Synthesis of phenylpiperazine derivatives of 1,4-benzodioxan as selective COX-2 inhibitors and anti-inflammatory agents

1-((2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)methyl)-4-substituted-phenylpiperazine moiety was prepared and has been found to be a new and selective ligand for the enzyme cyclooxygenase-2 (COX-2). The biological activity of compound 3k as anti-inflammatory agent was further investigated both in vitro and in vivo. Notably, compound 3k exhibited the best anti-inflammatory activity among the eleven designed compounds with no toxicity, as determined by the ulcerogenic activity. Computational docking studies also showed that compound 3k has interaction with COX-2 key residues in the active site. Compound 3k maybe a new anti-inflammatory lead-candidate as powerful and novel non-ulcerogenic.     

Identification of an imidazopyridine scaffold to generate potent and selective TYK2 inhibitors that demonstrate activity in an in vivo psoriasis model

Herein we report identification of an imidazopyridine class of potent and selective TYK2 inhibitors, exemplified by prototype 6, through constraint of the rotatable amide bond connecting the pyridine and aryl rings of compound 1. Further optimization led to generation of compound 30 that potently inhibits the TYK2 enzyme and the IL-23 pathway in cells, exhibits selectivity against cellular JAK2 activity, and has good pharmacokinetic properties. In mice, compound 30 demonstrated dose-dependent reduction of IL-17 production in a PK/PD model as well as in an imiquimod-induced psoriasis model. In this efficacy model, the IL-17 decrease was accompanied by a reduction of ear thickness indicating the potential of TYK2 inhibition as a therapeutic approach for psoriasis patients.