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Background Dengue disease is a global disease that has no effective treatment. The dengue virus (DENV) NS2B/NS3 protease complex is a target for designing specific antivirals due to its importance in viral replication and its high degree of conservation. Methods NS2B/NS3 protease complex structural information was employed to find small molecules that are capable of inhibiting the activity of the enzyme complex. This inhibitory activity was probed with in vitro assays using a fluorescent substrate and the complex NS2B/NS3 obtained by recombinant DNA techniques. HepG2 cells infected with dengue virus serotype 2 were used to test the activity against dengue virus replication. Results A total of 210,903 small molecules from PubChem were docked in silico to the NS2B/NS3 structure (PDB: 2FOM) to find molecules that were capable of inhibiting this protein complex. Five of the best 500 leading compounds, according to their affinity values (−11.6 and −13.5 kcal/mol), were purchased. The inhibitory protease activity on the recombinant protein and antiviral assays was tested. Conclusions Chemicals CID 54681617, CID 54692801 and CID 54715399 were strong inhibitors of NS2B/NS3, with IC 50 values (μM) and percentages of viral titer reductions of 19.9, 79.9%; 17.5, 69.8%; and 9.1, 73.9%, respectively. Multivariate methods applied to the molecular descriptors showed two compounds that were structurally different from other DENV inhibitors. General significance: This discovery opens new possibilities for obtaining drug candidates against Dengue virus. [ABSTRACT FROM AUTHOR]

The inhibition activities and mechanisms of four anthocyanins including cyanidin-3-glucoside, cyanidin-3,5-glucoside, cyanidin-3-rutinoside, and peonidin-3-glucoside, against porcine pancreatic α-amylase were investigated through in vitro and in silico studies. The in vitro inhibition study demonstrated that the four anthocyanins competitively inhibited porcine pancreatic α-amylase, which was later verified by the in silico molecular docking study that showed all the anthocyanins bound exclusively to the active site of porcine pancreatic α-amylase. Cyanidin-3-glucoside was found to have the highest inhibition activity with the K i value of 0.014 mM, followed by cyanidin-3-rutinoside, cyanidin-3,5-glucoside, and peonidin-3-glucoside with the K i value of 0.019, 0.020, and 0.045 mM, respectively. Results obtained from the in silico study also showed that the four anthocyanins were surrounded by the side chains of the active site of porcine pancreatic α-amylase, among which the side chain of GLU233 was supposed to play a key role in imparting the inhibition activity of anthocyanins. [ABSTRACT FROM AUTHOR]

Abstract: The arylquinazolines represent significant advances in the clinical management of breast cancer. Nevertheless some confirmatory studies must be considered to foster the use of anti-EGFR therapies including safety and clinical use. Two 4-arylaminoquinazoline derivatives, recently synthesized, were tested as kinase inhibitors and their citotoxicities showed potent growth inhibitory activity in breast tumor cell lines (MCF-7). The predicted complex structure of quinazoline inhibitors with EGFR protein from molecular docking provided a stereoview of the binding site correlated with structure activity, affording important information about structure-based drug design. [ABSTRACT FROM AUTHOR]

Abstract: Non-carboxylic acid containing bioisosteres of (5-arylidene-2,4-dioxothiazolidin-3-yl)acetic acids, which are active as aldose reductase (ALR2) inhibitors, were designed by replacing the carboxylic group with the trifluoromethyl ketone moiety. The in vitro evaluation of the ALR2 inhibitory effects of these trifluoromethyl substituted derivatives led to the identification of two inhibitors effective at low micromolar doses. It was further confirmed that a carboxylic chain on N-3 of the thiazolidinedione scaffold is a determining requisite to obtain the highest efficacy levels; however, it is not essential for the interaction with the target enzyme and it can be replaced by different polar groups, thus obtaining less ionised or unionised inhibitors. [Copyright &y& Elsevier]

Abstract: 17β-Oxazolinyl steroids 7a–g and 8a–g were synthesized. The Lewis acid-catalysed reactions of (20R)-3β-acetoxy-21-azidomethyl-20-hydroxypregn-5-ene with substituted aromatic aldehydes led to the formation of 3β-acetoxyandrost-5-enes substituted in position 17β with oxazolinyl residues (7a–g). Oppenauer oxidation of the 3β-hydroxy-exo-heterocyclic steroids yielded the corresponding Δ4-3-ketosteroids. The inhibitory effects (IC50) of both 3-hydroxy compounds 7a–g and their Δ4-3-keto counterparts 8a–g on rat testicular C17,20-lyase were investigated with an in vitro radioligand incubation technique. The 3-chlorophenyl- (8d), and the 4-bromophenyl-17β-(2-oxazolin-5-yl)androst-4-en-3-one derivatives (8f) were found to be modest inhibitors (IC50 =4.8 and 5.0μM, respectively). [Copyright &y& Elsevier]

Abstract: During the alkaline methanolysis of 3β-acetoxy-21-chloropregn-5-ene-20β-N-phenylurethane (4a), and its 4-monosubstituted (4b–e) and 3,5-disubstituted (4f) phenyl derivatives, cyclization occurs, in the course of which 17β-[3-(N-phenyl)-2-oxazolidon-5-yl]androst-5-en-3β-ol (5a) and its substituted phenyl derivatives (5b–f) are formed. The cyclization takes place with (N−-5) neighboring group participation. The reaction of 3β-acetoxy-21-azidopregn-5-en-20β-ol (3d) with triphenylphosphine gave 3β-acetoxy-21-phosphiniminopregn-5-en-20β-ol, which reacted in situ with carbon dioxide with the participation of the sterically favored 20β-OH to give the unsubstituted steroidal cyclic carbamate (8). Oppenauer oxidation of the 3β-hydroxy-exo-heterocyclic steroids (5a–f, 9) yielded the corresponding Δ4-3-ketosteroids (7a–f, 10). The inhibitory effects (IC50) of these compounds on rat testicular C17,20-lyase were investigated with an in vitro radioligand incubation technique. The N-unsubstituted 17β-(2-oxazolidon-5-yl)-androst-4-en-3-one derivative (10) was found to be a potent inhibitor (IC50 =3.0μM). [Copyright &y& Elsevier]

Abstract: Efficient strains of bacterial antagonists for Magnaporthe grisea were identified through laboratory dual-plate assays. Two bacterial strains of Pseudomonas fluorescens and two strains of Bacillus were tested against 30 isolates of M. grisea that cause Setaria blast for their inhibition of the fungus. On plates spread with the fungus mycelium, 12 of the isolates had a zone of inhibition caused by the bacteria that ranged between 2.5 and 3.0cm in diameter. In the field trails, the bacterial strains Pf-52 and KRU-22 suppressed disease by 86.64% and 87.87% respectively, in Setaria italica line 1, and 86.64% and 83.21% in line 2. The mixture of all four strains afforded 88.87% (line 1) and 88.80% (line 2) blast suppression and this was the highest level of biological blast control observed. In addition to disease suppression, the bacterial strains significantly increased root and shoot length when compared with untreated plants. Of the four strains, Pf-52, KRU-22 and the mixture of all four strains showed significant increases of root length of 10.02, 7.44 and 13.29cm (line 1), and 9.2, 5.7 and 13.11cm (line 2) in the root growth stage. As in the case of root length, Pf-52, KRU-22 and the mixture of all four strains showed significant increases of shoot length of 11.38, 10.42 and 11.99cm (line 1), and 9.87, 11.44 and 12.11cm (line 2) in the shoot growth stage. [Copyright &y& Elsevier]

Abstract: The inhibitory effects of four carbamate insecticides, methomyl, thiodicarb, carbofuran and carbosulfan, on acetylcholinesterase of male and female Carassius auratus were investigated in the laboratory. Kinetic constants, biomolecular rate constant (k i), carbamylation rate constant (k 2) and decarbamylation rate constant (k 3) were determined in vitro. The ratios of bimolecular rate constant (female/male) for AChE reacting with methomyl, thiodicarb, carbofuran and carbosulfan were 1.03, 2.44, 1.03 and 1.106, respectively. The k i of AChE for thiodicarb was significantly higher in female fish than in male fish (P <0.05). The ratios of carbamylation rate constant (female/male) for methomyl, thiodicarb, carbofuran and carbosulfan were 1.18, 4.29, 3.53, and 2.07, respectively. The k 2 values of AChE for the above four carbamates were significantly higher in females than in males. The ratios of the decarbamylation rate constant (female/male) for methomyl, thiodicarb, carbofuran and carbosulfan were 1.02, 1.39, 1.06, and 1.98, respectively. Only for carbosulfan, the decarbamylation rate of AChE was significantly higher in the female than in the male, indicating that AChE of females inhibited by carbosulfan recovered more quickly than that of males. The above results suggest that the female in the sensitivity of AChE to carbamates was different from the male fish. [Copyright &y& Elsevier]

During the alkaline methanolysis of 3β-acetoxy-21-chloromethyl-pregn-5-ene-20β-N-phenylurethane, and its p-substituted phenyl derivatives, cyclization occurs, in the course of which 17β-[3-(N-phenyl)tetrahydrooxazin-2-on-6-yl]androst-5-en-3β-ol and its p-substituted phenyl derivatives are formed. The cyclization takes place with (N--6) neighboring group participation. Oppenauer oxidation of the 3β-hydroxy-exo-heterocyclic steroids yielded the corresponding Δ4-3-ketosteroids. The structures of the new compounds were proved by IR, 1H and 13C NMR spectroscopy, using up-to-date measuring techniques such as 2D-COSY, HMQC, and HMBC. The inhibitory effects (CI50) of the Δ4-3-ketosteroids on 5α-reductase were studied. [Copyright &y& Elsevier]

Statine-based inhibitors of Plasmepsin II (PLMII) coupled with Primaquine have been designed using the `double-drug'' approach. The IC50 values for PLMII inhibition ranged from 0.59 to 400 nM and the best IC50 value for inhibition of Plasmodium falciparum growth in vitro was 0.4 μM, which represent a remarkable improvement compared to other statine-based PLMII inhibitors. [Copyright &y& Elsevier]

[Display omitted] • Synthesis of novel 16α,17α-oxazoline estrone derivatives. • Synthesis of 17α-hydroxy derivatives via Luche reduction. • Moderate antiproliferative activity against HeLa and MCF-7 cell lines. A simple and efficient synthesis of novel estrone 16α,17α-oxazoline derivatives substituted at the D ring (compounds 6a-g) is described. The reduction of 16α-azido-3-methoxyestra-1,3,5-trien-17-one (1) in methanol in the presence of CeCl 3 under the condition of the Luche reaction produced two epimeric azido alcohol (16α-azido-17α-hydroxy and 16α-azido-17β-hydroxy) derivatives of estra-1,3,5(10)-triene-3-methyl ether (compounds 2 and 3) in a yield of 90% and 7.6%. The reaction of the sterically unhindered 16α-azido-17α-hydroxy-estra-1,3,5(10)-triene-3-methyl ether (2) with a range of benzaldehydes under the condition of the Schmidt rearrangement yielded d -ring substituted estrone 16α,17α-oxazoline derivatives 6a-g. The in vitro antiproliferative activities of compounds 1, 2, 3, 6a-g were also determined by means of MTT assays on a panel of human cancer cell lines HeLa, SiHa, C-33 A, A2780, MCF-7, MDA-MB-231 and T47D. [ABSTRACT FROM AUTHOR]

• An in vitro protocol for mammalian systems is appropriate to marine invertebrates. • Carboxylesterase substrates adequacy differs between human and invertebrates. • The flame retardant TBBPA interferes in vitro with carboxylesterases of all groups. Carboxylesterases (CEs) are key enzymes which catalyse the hydrolysis reactions of multiple xenobiotics and endogenous ester moieties. Given their growing interest in the context of marine pollution and biomonitoring, this study focused on the in vitro sensitivity of marine invertebrate CEs to some pesticides, pharmaceuticals, personal care products and plastic additives to assess their potential interaction on this enzymatic system and its suitability as biomarkers. Three bivalves, one gastropod and two crustaceans were used and CEs were quantified following current protocols set for mammalian models. Four substrates were screened for CEs determination and to test their adequacy in the hepatic fraction measures of the selected invertebrates. Two commercial recombinant human isoforms (hCE1 and hCE2) were also included for methodological validation. Among the invertebrates, mussels were revealed as the most sensitive to xenobiotic exposures while gastropods were the least as well as with particular substrate-specific preferences. Among chemicals of environmental concern, the plastic additive tetrabromobisphenol A displayed the highest CE-inhibitory capacity in all species. Since plastic additives easily breakdown from the polymer and may accumulate and metabolise in marine biota, their interaction with the CE key metabolic/detoxification processes may have consequences in invertebrate's physiology, affect bioaccumulation and therefore trophic web transfer and, ultimately, human health as shellfish consumers. [ABSTRACT FROM AUTHOR]

• Carboxylesterases are mainly located in liver and plasma of Sparus aurata. • The same isozymes seemed to hydrolyse the three substrates studied. • Hepatic carboxylesterase could have a protective role of brain AChE. • Hepatic carboxylesterase showed its utility as biomarker of pharmaceuticals. Organophosphorus (OP) and carbamate (CB) pesticides cause inhibition of acetylcholinesterase (AChE, which is the target enzyme) and carboxylesterase (CbE). However, some studies have suggested that CbE could have a potential protective role on AChE since CbE seems to be more sensitive to the inhibition by OP and CB compounds than the target enzyme. In addition, there is a great deal of concern about the presence of pharmaceutical products in the seas, and some studies have pointed out the utility of CbE as a biomarker and scavenger of them. Thus, our main aim was to study the inhibition caused by the OPs chlorpyrifos-oxon (CP-O) and dichlorvos (DCV), and the carbamate eserine on the hepatic CbE and the brain AChE of Sparus aurata. Another goal was to determine the hepatic CbE inhibition caused by ibuprofen, fenofibrate, simvastatin, carbamazepine, and triclosan. To achieve these goals, we studied the localisation of CbE in Sparus aurata and estimated the kinetic parameters of hepatic CbE. The results of this study indicate that most CbE activity occurs in the plasma and liver. However, the kinetic parameters of hepatic CbE measured on the three substrates used appeared to be very similar. Hepatic CbE was more sensitive to DCV than brain AChE, suggesting a possible protective role of CbE on AChE. Finally, CbE was shown to be sensitive to the inhibition caused by triclosan and simvastatin, indicating its utility as a biomarker and as a scavenger of these compounds to reduce the possible adverse effects on the organisms. [ABSTRACT FROM AUTHOR]

Tetrabromobisphenol A (TBBPA), a brominated flame retardant used in synthetic polymers and electronics, is present in the aquatic environment and recent evidence suggests it can be potentially biomagnified in the marine ecosystem. However, the toxicity of TBBPA in the marine biota has not been investigated in detail. In this study we aimed to understand the role of carboxylesterases (CEs) in xenobiotic metabolism under the exposure of marine organisms to a chemical of environmental concern, TBBPA. Specifically, we tested for in vitro inhibition of CE activity in a range of marine organisms covering different ecological niches, from species from low (mussels and copepods), medium (sardines and anchovies) and high trophic levels (tuna). The results revealed that the highest inhibition of CE activity to 100 μM TBBPA was recorded in mussels (66.5% inhibition) and tunids (36.3–76.4%), whereas copepods and small pelagic fish showed comparatively lower effects (respectively, 30% and 36.5–55.6%). Our results suggest that CE-mediated detoxification and physiological processes could be compromised in TBBPA-exposed organisms and could ultimately affect humans as many of them are market species. Image 1 • TBBPA inhibits carboxylesterases in a substrate dependent manner. • Butyrate esters are more sensitive than naphthyl derived forms in mussels. • Carboxylesterase inhibition by TBBPA in marine organisms is species dependent. • High trophic level predators seem to be more sensitive to TBBPA than primary consumers. [ABSTRACT FROM AUTHOR]