Natural mimetic 4-benzyloxychalcones as potent pancreatic lipase inhibitors: Virtual screening,synthesis and biological evaluation

Pancreatic lipase is a well-known target for obesity drug development. The inhibition of this enzyme mitigates the digestion and absorption of dietary fat. Despite some inconvenient side effects, orlistat is currently the only medication with FDA approval that works by inhibition of pancreatic lipase. Several natural flavonoids, including chalcones, have been reported to possess promising lipase inhibitory activity. In this paper, we describe the evaluation of the lipase inhibitory activity of our in-house natural mimetic chalcone library via virtual screening, followed by the synthesis and biological evaluation of the hits. Compound C82 showed low-micromolar activity against pancreatic lipase in vitro (IC₅₀ = 1.01 ± 0.86 µM). The interaction of C82 and lipase was additionally confirmed by a fluorescence quenching study.     

Synthesis,molecular docking and biological evaluation of some benzimidazole derivatives as potent pancreatic lipase inhibitors

In this study, a new series of benzimidazole and bisbenzimidazole derivatives were prepared via the reaction of iminoester hydrochlorides and o-phenylenediamines and then screened for their lipase inhibition properties. Among the synthesized molecules, compounds 7a, 8a and 8c showed the best inhibitory effect against lipase enzyme with IC₅₀ values of 1.72 ± 0.12 µM, 1.92 ± 0.28 and 0.98 ± 0.07 µM, respectively. Moreover, molecular modeling studies were performed in order to understand to the inhibitory activity of the molecules. Binding poses of the studied compounds were determined at the target sites using induced fit docking (IFD) algorithms.     

Design,synthesis and molecular modeling study of certain VEGFR-2 inhibitors based on thienopyrimidne scaffold as cancer targeting agents

Different series of novel thieno [2,3-d]pyrimidine derivative (9a-d,10a-f,l,m and 15a-m) were designed, synthesized and evaluated for their ability to in vitro inhibit VEGFR-2 enzyme. Also, the cytotoxicity of the final compounds was tested against a panel of 60 different human cancer cell lines by NCI. The VEGFR-2 enzyme inhibitory results revealed that compounds 10d, 15d and 15 g are among the most active inhibitors with IC₅₀ values of 2.5, 5.48 and 2.27 µM respectively, while compound 10a remarkably showed the highest cell growth inhibition with mean growth inhibition (GI) percent of 31.57%. It exhibited broad spectrum anti-proliferative activity against several NCI cell lines specifically on human breast cancer (T7-47D) and renal cancer (A498) cell lines of 85.5% and 77.65% inhibition respectively. To investigate the mechanistic aspects underlying the activity, further biological studies like flow cytometry cell cycle together with caspase-3 colorimetric assays were carried on compound 10a. Flow cytometric analysis on both MCV-7 and PC-3 cancer cells revealed that it induced cell-cycle arrest in the G0-G1phase and reinforced apoptosis via activation of caspase-3. Furthermore, molecular modeling studies have been carried out to gain further understanding of the binding mode in the active site of VEGFR-2 enzyme and predict pharmacokinetic properties of all the synthesized inhibitors.     

Synthesis,characterization, theoretical,anti-bacterial and molecular docking studies of quinoline based chalcones as a DNA gyrase inhibitor

A series of fourteen (A₁–A₁₄) new qunioline based chalcones were synthesized by condensing 2,7-dichloro-8-methyl-3-formyl quinoline with acetophenone and acetylthiophenes, and subsequently characterized by IR, NMR and Mass spectroscopy. All the compounds were screened for antibacterial activities and found potentially active antibacterial agents. Bioassay, theoretical and dockings studies with DNA gyrase (the enzyme required for super coiling of DNA of bacteria) results showed that the type and positions of the substituents seemed to be critical for their antibacterial activities. The bromo and chloro substituted chalcone displayed high anti-bacterial activity. The A₄ and A₆ showed high interaction with DNA gyrase, contributing high free binding energy (ΔG −8.18 and −8.88 kcal).     

Improvement of catalytic activity of Candida rugosa lipase in the presence of calix[4]arene bearing iminodicarboxylic/phosphonic acid complexes modified iron oxide nanoparticles

In the present study, iron oxide magnetite nanoparticles, prepared through a co-precipitation method, were coated with phosphonic acid or iminodicarboxylic acid derivatives of calix[4]arene to modulate their surfaces with different acidic groups. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through sol–gel encapsulation. The catalytic activities and enantioselectivities of the two encapsulated lipases in the hydrolysis reaction of (R/S)-naproxen methyl ester and (R/S)-2-phenoxypropionic acid methyl ester were assessed. The results showed that the activity and enantioselectivity of the lipase were improved when the lipase was encapsulated in the presence of calixarene-based additives; the encapsulated lipase with the phosphonic acid derivative of calix[4]arene had an excellent rate of enantioselectivity against the (R/S)-naproxen methyl and (R/S)-2-phenoxypropionic acid methyl esters, with E = 350 and 246, respectively, compared to the free enzyme. The encapsulated lipases (Fe-Calix-N(COOH)) and (Fe-Calix–P) showed good loading ability and little loss of enzyme activity, and the stability of the catalyst was very good; they only lost 6–11% of the enzyme’s activity after five batches.     

Discovery of acylguanidine oseltamivir carboxylate derivatives as potent neuraminidase inhibitors

In search of novel anti-influenza agents with higher potency, a series of acylguanidine oseltamivir carboxylate analogues were synthesized and evaluated against influenza viruses (H1N1 and H3N2) in vitro. The representative compounds with strong inhibitory activities (IC₅₀ <40 nM) against neuraminidase (NA) were further tested against the NA from oseltamivir-resistant strain (H259Y). Among them, compounds 9 and 17 were potent NA inhibitors that exhibited a 5 and 11-fold increase in activity comparing with oseltamivir carboxylate (2, OC) against the H259Y mutant, respectively. Furthermore, the effect against influenza virus H259Y mutant (H1N1) replication and cytotoxicity assays indicated that compounds 9 and 17 exhibited a 20 and 6-fold increase than the parent compound 2, and had no obvious cytotoxicity in vitro. Moreover, the molecular docking studies revealed that the docking modes of compounds 9 and 17 were different from that of oseltamivir, and the new hydrogen bonds and hydrophobic interaction were formed in this case. This work provided unique insights in the discovery of potent inhibitors against NAs from wild-type and oseltamivir-resistant strains.     

Development of 2-aryl substituted quinazolin-4(3H)-one,pyrido[4,3-d]pyrimidin-4(3H)-one and pyrido[2,3-d]pyrimidin-4(3H)-one derivatives as microsomal prostaglandin E2 synthase-1 inhibitors

mPGES-1 is inducible terminal synthase acting downstream of COX enzymes in arachidonic acid pathway, regulates the biosynthesis of pro-inflammatory prostaglandin PGE₂. Cardiovascular side effect of coxibs and NSAIDs, selective for COX-2 inhibition, stimulated interest in mPGES-1, a therapeutic target with potential to deliver safe and effective anti-inflammatory drugs. The synthesis and structure activity relationship of a series of compounds from 2-aryl substituted quinazolin-4(3H)-one, pyrido[4,3-d]pyrimidin-4(3H)-one and pyrido[2,3-d]pyrimidin-4(3H)-one scaffolds as mPGES-1 inhibitor are discussed. A set of analogs (28, 48, 49) were identified with <10 nM potencies in the recombinant human mPGES-1 enzyme and in the A549 cellular assays. These analogs were also found to be potent in the human whole blood assay (<400 nM). Furthermore, the representative compound 48 was shown to be selective with other prostanoid synthases and was able to effectively regulate PGE₂ biosynthesis in clinically relevant inflammatory settings, in comparison with celecoxib.     

Design,synthesis and evaluation of N-[(3S)-pyrrolidin-3-yl]benzamides as selective noradrenaline reuptake inhibitors: CNS penetration in a more polar template

Derivatives of N-[(3S)-pyrrolidin-3-yl]benzamides are disclosed as a new series of noradrenaline reuptake inhibitors (NRI). Structure–activity relationships established that potent NRI activity could be achieved by appropriate substitution at the 2-position of the phenyl ring; consequently, selective NRIs and dual NSRIs were prepared. Benzamide 11e was identified as a potent NRI with good selectivity over SRI and DRI, good in vitro metabolic stability, weak CYP inhibition and low affinity for ion channels. Evaluation in vivo, in rat microdialysis experiments, showed 11e increased noradrenaline levels by up to 350% confirming good CNS penetration. Benzamide 11e was differentiated from previous NRIs as it was significantly less lipophilic (Δclog P ?0.9).     

Synthesis,anti-HIV activity,integrase enzyme inhibition and molecular modeling of catechol,hydroquinone and quinol labdane analogs

Labdane analogs with o-quinol, catechol and hydroquinone moiety have been synthesized using Diels–Alder reaction of methyl 3,4-dioxocyclohexa-1,5-diene-carboxylate, 3,4-dioxocyclohexa-1,5-diene-carboxylic acid and 3,6-dioxocyclohexa-1,4-dienecarboxylic acid with mono terpene 1,3-dienes, namely ocimene and myrcene. The resulting molecules and their derivatives were evaluated for their anti-HIV-1 activity using TZM-bl cell based virus infectivity assay. Two molecules 13 and 18 showed anti-HIV activity with IC₅₀ values 5.0 (TI = 11) and 4.6 (TI = 46) μM, respectively. The compounds 17, 18 and 20 showed efficacy against HIV-1 integrase activity and showed inhibition with IC₅₀ 13.4, 11.1 and 11.5 μM, respectively. The HIV-1 integrase inhibition activity of these synthetic molecules was comparable with integric acid, the natural fungal metabolite. Molecular modeling studies for the HIV-1 integrase inhibition of these active synthetic molecules indicated the binding to the active site residues of the enzyme.     

Design, Syntheses, and Characterization of a Sterically Encumbered Dioxo Molybdenum (VI) Core

Dioxo-Mo^VI complexes of general formula Tp^∗MoO₂(p-SC₆H₄Dn) (6a-6c) (where Tp^∗ = hydrotris(3,5-dimethyl-pyrazol-1-yl)borate and Dn = dendritic unit) have been synthesized and characterized by spectroscopy and mass spectrometry. ¹H NMR spectra of the metal complexes indicate that the C_s local symmetry about the metal core does not change by the incorporation of dendritic functionality at the thiophenolato ring. Electrochemical data show a ∼20 mV change in the redox potential in the complexes with dendritic ligands suggesting a very small perturbation in the redox orbital, which is also supported by small changes in the electronic spectra. The peak-to peak separation (ΔE_p) increases from 125 mV in 6(a) to 240 mV in 6(c), suggesting sluggish electron transfer in molecules with larger dendritic ligands.     

Tyrosinase activity of Greyia flanaganii (Bolus) constituents

Hyper-pigmentation of the skin is a common problem that is prevalent in middle aged and elderly people. It is caused by over production of melanin. Tyrosinase is known to be the key enzyme in melanin production. Ethanolic extract of Greyia flanaganii leaves showed significant (P < 0.05) antityrosinase activity exhibiting the IC₅₀ of 32.62 μg/ml. The total extract was further investigated for its toxicity and effect on melanin production by melanocytes cells, and showed significant inhibition (P < 0.05) (20%) of melanin production at 6.25 μg/ml and low levels of cytotoxicity (IC₅₀ < 400 μg/ml). The amount of antioxidants necessary to decrease the initial DPPH absorbance by 50% (EC₅₀) by the total ethanolic extract was found to be 22.01 μg/ml. The effect of G. flanaganii against acne causing bacteria, Propionibacterium acnes, was investigated using microdilution assay. The MIC of the extract of G. flanaganii was found to be 250 μg/ml. Bioassay-guided fractionation led to the isolation of (3S)-4-hydroxyphenethyl 3-hydroxy-5-phenylpentanoate (1), 2′,4′,6′-trihydroxydihydrochalcone (2), 2′,6′,4-trihydroxy-4′-methoxydihydrochalcone (3), 2′,6′-dihydroxy-4′-methoxydihydrochalcone (4), 5,7-dihydroxyflavanone [(2S)-pinocembrin] (5), 2′,6′-dihydroxy-4′,4-dimethoxy dihydrochalcone (6) and (2R,3R)-3,5,7-trihydroxy-3-O-acetylflavanone (7). The isolated compounds were tested for their antioxidant, cytotoxicity, tyrosinase inhibition and antibacterial activities. Compound 2 exhibited significant (P < 0.05) antityrosinase activity exhibiting the IC₅₀ of 69.15 μM. The isolated compounds showed low toxicity of the cells with reduction of melanin content of the cells. All compounds tested showed good radical scavenging activity. These data indicates that G. flanaganii extract and its isolated phenolic constituents could be possible skin lightening agents.     

Effect of access to outdoor grazing and stocking density on space and pasture use,behaviour, reactivity,and growth traits of weaned rabbits

In a context of evolving concern over housing conditions of farmed rabbits, we developed a housing system that allows access to an outdoor area. The aim was to study the health status, growth and behaviour of rabbits raised at two stocking densities with access to a paddock, or not. We distributed 299 weaned rabbits in four groups (YH: 100, NH: 99, YL: 50 and NL: 50) using a 2 × 2 factorial design including access (Y: yes) or not (N: not) to a 23 m² paddock and the indoor stocking density (H, high: 17 or L, low: 9 rabbits/m²). We measured the growth and health status of each animal weekly for 42 days (from 31 to 73 days of age) and performed reactivity tests to a new environment, a human and new object. We also assessed the rabbits’ behaviour at days 26 and 40 by doing a visual scan of each animal at regular time intervals. Our results showed that stocking density had no effect on mortality, but mortality tended to increase with outdoor access from 3.0% to 7.0% (P < 0.10). Although the stocking density had no effect on average daily gain, it was higher in rabbits in the N group than in the Y group (+3.6 g/day; P < 0.05). Rabbits entered the paddocks for the first time in less time at the beginning of the trial (50 s at day 3 vs 10 min at day 31; P < 0.001). The proportion of rabbits outside after 20 min of the new environment test was higher among rabbits in the L group than in the H group (+24% points at day 3 and +11% points at day 20; P < 0.001). Regardless of the stocking density, more rabbits in the N group touched the experimenter’s hand (16% vs 27%; P < 0.05) and the new object (34% vs 20%; P < 0.05) than rabbits in the Y group. Inactivity was more frequent in rabbits inside the pens than in the paddocks (70.0% vs 34.2% at days 26 and 40; P < 0.05). Locomotion was more frequent in the paddocks than in the indoor pens (20.0% vs 7.2% at days 26 and 40; P < 0.05). The stocking density did not affect the behavioural traits measured. In conclusion, providing rabbits access to a paddock could allow them to fulfil some natural behaviours but slightly reduced their growth.     

Synthesis,screening and docking analysis of hispolon analogs as potential antitubercular agents

A series of 20 hispolons/dihydrohispolons were synthesized and characterized by spectral data. These compounds were subjected to in vitro antitubercular activity screening against Mycobacterium tuberculosis (H37Rv) strain. The synthesized compounds showed varied antitubercular activity ranging from 100 to 1.6 μg/mL. Among the screened compounds, four compounds (H1, H2, H3 and H15) have shown moderate activity with MIC 25 μg/mL. Potent activities were observed for the dihydrohispolon derivative H14 (MIC 1.6 μg/mL) followed by H13 (6.25 μg/mL) and H17 (12.5 μg/mL), H19 (3.125 μg/ML). Docking simulations gave good insights on the possible interactions between the tested compounds and β-keto acyl synthase enzyme (mtbFabH). Drug-inhibitor combination studies showed no synergism with the drugs targeting mycolic acid biosynthesis (isoniazid, ethambutol and thiolactomycin, a specific inhibitor of KAS-B enzyme) but showed significant synergism with other drugs including rifampicin and ciprofloxacin ascertaining the drug target for hispolons as inhibition of mycolic acid biosynthesis, probably via mtbFabH.     

5-Nitro-2-furoic acid hydrazones: Design,synthesis and in vitro antimycobacterial evaluation against log and starved phase cultures

Various 5-nitro-2-furoic acid hydrazones were synthesized and evaluated for in vitro activities against log and starved phase culture of two mycobacterial species and Mycobacterium tuberculosis (MTB) isocitrate lyase (ICL) enzyme inhibition studies. Among twenty one compounds, 5-nitro-N′-[(5-nitro-2-furyl)methylidene]-2-furohydrazide (4o) was found to be the most active compound in vitro with MICs of 2.65 and 10.64 μM against log- and starved-phase culture of MTB. Compound 4o also showed good enzyme inhibition of MTB ICL at 10 μM. The docking studies also confirmed the binding potential of the compounds at the ICL active site.     

Lewis-base copper(I) formates: Synthesis, reaction chemistry, structural characterization and their use as spin-coating precursors for copper deposition

Consecutive synthesis methodologies for the preparation of a series of copper(I) formates [L_mCuO₂CH] (L = ⁿBu₃P: 4a, m = 1; 4b, m = 2; 5, L = [Ti](CCSiMe₃)₂, m = 1, [Ti] = (η⁵-C₅H₄SiMe₃)₂Ti) and [L_mCuO₂CH·HO₂CR] (L = ⁿBu₃P: 7a, m = 1, R = H; 7b, m = 2, R = H; 7c, m = 2, R = Me; 7d, m = 2, R = CF₃; 7e, m = 2, R = Ph. L = (^cC₆H₁₁)₃P, R = H: 8a, m = 2; 8b, m = 3. L = (CF₃CH₂O)₃P, R = H: 9a, m = 2; 9b, m = 3. L = (CH₃CH₂O)₃P, R = H: 10a, m = 2; 10b, m = 3. L = [Ti](CCSiMe₃)₂; m = 1: 11a, R = H; 11b, R = Ph) is reported using [CuO₂CH] (1) and L (2a, L = ⁿBu₃P; 2b, L (^cC₆H₁₁)₃P; 2c, L = (CF₃CH₂O)₃P; 2d, L = (CH₃CH₂O)₃P; 3, L = [Ti](CCSiMe₃)₂) as key starting materials. Addition of formic acid (6a) or carboxylic acid HO₂CR (6b, R = Me; 6c, R = CF₃; 6d, R = Ph) to the afore itemized copper(I) formates 4 and 5 gave metal-organic or organometallic 7-11. The molecular structures of 8a and 11a in the solid state are reported showing a threefold coordinated copper(I) ion, setup by either two coordinatively-bonded phosphorus atoms and one formate oxygen atom (8a) or two π-bonded alkyne ligands and one oxygen atom (11a). A formic acid molecule is additionally hydrogen-bonded to the CuO₂CH moiety. The use of 7b as suitable precursor for the deposition of copper onto TiN-coated oxidized silicon wafers by the spin-coating process below 300 °C is described. Complex 7b offers an appropriate transformation behavior into metal phase by an elimination-decarboxylation mechanism. The morphology of the copper films strongly depends on the annealing conditions. A closed grain network densified by a post-treatment is obtained (8 °C min⁻¹, N₂/H₂ carrier gas). Hydrogen post-anneal to 420 °C after film deposition gave a copper film showing resistivities from 2.5 to 3.7 μΩ cm. This precursor was also used for gap-filling processes.     

Synthesis and isomerisation of two metallated N,O-complexes of ruthenium: Models for the Murai reaction

Two isomers of the N,O-coordinated acetylpyrrolyl complex [Ru(PPh₃)₂(CO)(NC₄H₃C(O)CH₃)H] {cis-N,H (1) and trans-N,H (2)} have been prepared as models for catalytic intermediates in the Murai reaction. Complex 2 isomerises to 1 upon heating via a dissociative pathway (ΔH^‡ = 195 ± 41 kJ mol⁻¹; ΔS^‡ = 232 ± 62 J mol⁻¹ K⁻¹); the mechanism of this process has been modeled using density functional calculations. Complex 2 displays moderate catalytic activity for the Murai coupling of 2′-methylacetophenone with trimethylvinylsilane, but 1 proved to be catalytically inactive under the same conditions.     

Design,synthesis, biological evaluation and dynamics simulation of indazole derivatives with antiangiogenic and antiproliferative anticancer activity

VEGFR-2 has a pivotal role in promoting cancer angiogenesis. Herein, two series of novel indazole-based derivatives were designed, synthesized and evaluated for their in vitro inhibitory action against VEGFR-2 kinase enzyme. The second series 11a-e exhibited better potency than the first one 7a-d and 8a-f. Compounds 11b, 11c and 11e exhibited the most potent action, with IC₅₀ of 5.4 nM, 5.6 nM and 7 nM, respectively. As a measure of cellular VEGFR-2 inhibition, compounds 11b and 11c showed strong inhibition of human umbilical vein endothelial cells (HUVEC) proliferation with 80% and 99.6% inhibition at 10 μM concentration, respectively. Attempting to interpret SAR of the synthesized compounds, and provide a basis for further optimization; a comprehensive modeling study was implemented. Molecular docking, dynamics simulation and free energy calculation of the synthesized compounds along with known VEGFR-2 inhibitors were applied. The study illustrated the effect of several factors on VEGFR-2 inhibition, such as the interaction with solvent accessible region of the enzyme, the presence of NH linker and the degree of conformational restriction. Finally, our compounds were evaluated for their in vitro anti-proliferative effect against the full NCI panel of cancer cell lines, where compounds 11a and 11c displayed mean GI% of 93 and 130%, respectively, and showed partly a better behavior than the FDA approved drug sorafenib, with respect to activity (GI₅₀) and safety (LC₅₀) against several cell lines. Thus, compound 11c represents a promising candidate for cancer treatment through antiangiogenic dependent and antiangiogenic independent modes of action.     

Effects of enzyme-treated soy protein on performance,digestive enzyme activity and mRNA expression of nutrient transporters of laying hens fed different nutrient density diets

It has been shown that enzyme-treated plant protein can increase performance and promote intestinal health, and save dietary protein. However, our understanding of the effects of enzyme-treated soy protein on performance and intestine function in laying hens, and its rational use, remains limited. The experiment was conducted to study the effect of enzyme-treated soy protein (ETSP) in different nutrient density diets on performance, egg quality, digestive enzyme activity and mRNA expression of amino acid transporters of laying hens. A total of 1 200 Lohmann laying hens (52 wk of age) was randomly divided into a 3 × 2 factorial design that included three nutrient levels: [positive control (PC), metabolisable energy (ME): 2 680 kcal/kg, CP: 15.5%; negative control 1 (NC1), ME: 2 630 kcal/kg, CP: 15%; negative control 2 (NC2), ME:2 580 kcal/kg, CP: 14.5%] and 2 ETSP levels (0 and 0.5%) for 12 weeks. Each treatment had 10 replicates with 20 birds. With the decrease of dietary nutrition density, egg production rate (P = 0.07) and feed conversion ratio (FCR) (P = 0.06) were reduced. Yolk colour was decreased, and yolk index was increased. Supplemented ETSP improved FCR (P = 0.05) and qualified egg rate (P < 0.05). The mass loss rate of egg was decreased after storage for 30 days (P < 0.05). An interaction between nutrient density and ETSP was observed on albumen height and Haugh unit (P < 0.05), and the effects were most noticeable in hens fed 0.5% ETSP in NC2 group. An increase in the activity of trypsin in duodenum (P < 0.05) and the relative expressions of jejunum peptide transporter 1 (PepT1) (P < 0.05) and B⁰ system neutral amino acid transport carrier (B⁰AT) mRNA (P < 0.01) was observed during ETSP supplementation. The nutrient density and ETSP supplementation had no significant effect on microbiota in the cecal contents. Overall, the results in this study indicated that the ME decreased 100 kcal/kg and CP decreased 1% in diet of laying hens had a decreasing trend on production performance, no effects on enzyme activity, amino acid transporter mRNA, and gut microbiota, whereas 0.5% ETSP can increase activity of trypsin, PepT1 and B⁰AT mRNA relative expressions, and improve FCR, qualified egg rate.