Cardiac myosin-binding protein C interaction with actin is inhibited by compounds identified in a high-throughput fluorescence lifetime screen.

Cardiac myosin-binding protein C (cMyBP-C) interacts with actin and myosin to modulate cardiac muscle contractility. These interactions are disfavored by cMyBP-C phosphorylation. Heart failure patients often display decreased cMyBP-C phosphorylation, and phosphorylation in model systems has been shown to be cardioprotective against heart failure. Therefore, cMyBP-C is a potential target for heart failure drugs that mimic phosphorylation or perturb its interactions with actin/myosin. Here we have used a novel fluorescence lifetime-based assay to identify small-molecule inhibitors of actin-cMyBP-C binding. Actin was labeled with a fluorescent dye (Alexa Fluor 568, AF568) near its cMyBP-C binding sites; when combined with the cMyBP-C N-terminal fragment, C0-C2, the fluorescence lifetime of AF568-actin decreases. Using this reduction in lifetime as a readout of actin binding, a high-throughput screen of a 1280-compound library identified three reproducible hit compounds (suramin, NF023, and aurintricarboxylic acid) that reduced C0-C2 binding to actin in the micromolar range. Binding of phosphorylated C0-C2 was also blocked by these compounds. That they specifically block binding was confirmed by an actin-C0-C2 time-resolved FRET (TR-FRET) binding assay. Isothermal titration calorimetry (ITC) and transient phosphorescence anisotropy (TPA) confirmed that these compounds bind to cMyBP-C, but not to actin. TPA results were also consistent with these compounds inhibiting C0-C2 binding to actin. We conclude that the actin-cMyBP-C fluorescence lifetime assay permits detection of pharmacologically active compounds that affect cMyBP-C-actin binding. We now have, for the first time, a validated high-throughput screen focused on cMyBP-C, a regulator of cardiac muscle contractility and known key factor in heart failure.

A reactive oxygen species Ca2+ signalling pathway identified from a chemical screen for modifiers of sugar-activated circadian gene expression.

Sugars are essential metabolites for energy and anabolism that can also act as signals to regulate plant physiology and development. Experimental tools to disrupt major sugar signalling pathways are limited. We performed a chemical screen for modifiers of activation of circadian gene expression by sugars to discover pharmacological tools to investigate and manipulate plant sugar signalling. Using a library of commercially available bioactive compounds, we identified 75 confident hits that modified the response of a circadian luciferase reporter to sucrose in dark-adapted Arabidopsis thaliana seedlings. We validated the transcriptional effect on a subset of the hits and measured their effects on a range of sugar-dependent phenotypes for 13 of these chemicals. Chemicals were identified that appear to influence known and unknown sugar signalling pathways. Pentamidine isethionate was identified as a modifier of a sugar-activated Ca2+ signal that acts as a calmodulin inhibitor downstream of superoxide in a metabolic signalling pathway affecting circadian rhythms, primary metabolism and plant growth. Our data provide a resource of new experimental tools to manipulate plant sugar signalling and identify novel components of these pathways.

Biochar amendment reduced the risk associated with metal uptake and improved metabolite content in medicinal herbs.

Contaminations of heavy metals such as lead (Pb) and cadmium (Cd) in medicinal plants (MPs) not only restrict their safe consumption due to health hazards but also lower their productivity. Biochar amendments in the soil are supposed to immobilize the toxic metals, improve the soil quality and agricultural productivity. However, the impact of biochar on growth attributes, metal accumulation, pharmacologically active compounds of MPs, and health risk is less explored. An experiment was performed on three medicinal plants (Bacopa monnieri (L.), Andrographis paniculata (Burmf.) Nees, and Withaniasomnifera (L.)) grown in a greenhouse in soil co-contaminated with Pb and Cd (at two concentrations) without and with biochar amendments (2 and 4% application rates). The fractionation of Pb and Cd, plant growth parameters, stress enzymes, photosynthetic capacity, pharmacologically active compounds, nutrient content, uptake and translocation of metals, antioxidant activities, and metabolite content were examined in the three MPs. The accumulation of Pb and Cd varied from 3.25-228 mg kg1 and 1.29-20.2 mg kg-1 , respectively, in the three MPs, while it was reduced to 0.08-18 mg kg-1 and 0.03-6.05 mg kg-1 upon biochar treatments. Plants grown in Pb and Cd co-contaminated soil had reduced plant biomass (5-50% depending on the species) compared to control and a deleterious effect on photosynthetic attributes and protein content. However, biochar amendments significantly improved plant biomass (21-175%), as well as photosynthesis attributes, chlorophyll, and protein contents. Biochar amendments in Pb and Cd co-contaminated soil significantly reduced the health hazard quotient (HQ) estimated for the consumption of these medicinal herbs grown on metal-rich soil. An enhancement in secondary metabolite content and antioxidant properties was also observed upon biochar treatments. These multiple beneficial effects of biochar supplementation in Pb and Cd co-contaminated soil suggested that a biochar amendment is a sustainable approach for the safe cultivation of MPs. This article is protected by copyright. All rights reserved.

Recent Advances in the Synthesis and Biomedical Applications of Heterocyclic NO-Donors.

Nitric oxide (NO) is a key signaling molecule that acts in various physiological processes such as cellular metabolism, vasodilation and transmission of nerve impulses. A wide number of vascular diseases as well as various immune and neurodegenerative disorders were found to be directly associated with a disruption of NO production in living organisms. These issues justify a constant search of novel NO-donors with improved pharmacokinetic profiles and prolonged action. In a series of known structural classes capable of NO release, heterocyclic NO-donors are of special importance due to their increased hydrolytic stability and low toxicity. It is no wonder that synthetic and biochemical investigations of heterocyclic NO-donors have emerged significantly in recent years. In this review, we summarized recent advances in the synthesis, reactivity and biomedical applications of promising heterocyclic NO-donors (furoxans, sydnone imines, pyridazine dioxides, azasydnones). The synthetic potential of each heterocyclic system along with biochemical mechanisms of action are emphasized.

Stereoselective transport of 2-aryl propionic acid enantiomers in porous media subjected to chiral organic acids.

The study examined the transport behavior of the 2-aryl propionic acid (2-APA) chiral pharmaceutical enantiomers by means of a laboratory-scale saturated quartz sand column experiment. Four typical of 2-APA and their enantiomers were selected for the study under different types of chiral organic acids (COAs)-mediated effects. Differences in the transport of the 2-APA enantiomeric pairs have been identified in response to various pH, types of COAs, and enantiomeric structures of COAs. Redundancy analysis identified the factors responsible for the largest differences in transport of 2-APA enantiomeric pairs, while spectroscopic characterization and density function theory (DFT) studies elucidated the underlying mechanisms contributing to the differences in transport of enantiomeric pairs. Obvious correlations among homochirality or heterochirality between COAs and 2-APA enantiomeric pairs were observed for changes in the mobility of 2-APA. The results indicate widespread COAs significantly affect the transport behavior of chiral man-made chemicals, suggesting more attention is needed to fill the gap in the perception of the transport behavior of chiral compounds.

Interplay of Halogen and Hydrogen Bonding through Co-Crystallization in Pharmacologically Active Dihydropyrimidines: Insights from Crystal Structure and Energy Framework.

A solvent-assisted grinding method has been used to prepare co-crystals in substituted dihydropyrimidines (DHPM) that constitutes pharmacologically active compounds. These were characterized using FT-IR, PXRD, and single-crystal X-ray diffraction. In order to explore the possibility of formation of halogen (XB) and hydrogen bonding (HB) synthons in the solid state, co-crystallization attempts of differently substituted DHPM molecules, containing nitro, hydoxy, and chloro substituents, with different co-formers, such as 1,4-diiodo tetrafluorobenzene (1,4 DITFB) and 3-nitrobenzoic acid (3 NBA) were performed. The XB co-crystals (C2aXB, C2bXB, and C2cXB) prefer the formation of C-I⋅⋅⋅O/C-I⋅⋅⋅S XB synthon, whereas the HB co-crystal (C2dHB) is stabilized by N-H⋅⋅⋅O H-bond formation. Hirshfeld surface analysis revealed that the percentage contribution of intermolecular interactions for XB co-crystals prefer equal contribution of XB synthon along with HB synthon. Furthermore, the interaction energy was analyzed using energy frameworks, which suggests that their stability, a combination of electrostatics and dispersion, is enhanced through XB/HB in comparison to the parent DHPMs.

Synthesis of Pharmacological Relevant 1,2,3-Triazole and Its Analogues-A Review.

In this review, authors focus mostly on the various synthetic strategies developed so far for 1,2,3- triazole scaffold and its derivatives via different approaches such as metal-free, metal assisted or bimetallic. A brief overview of applications of the very important 1,2,3-triazole scaffold along with pharmacological activity is also discussed. Synthetic strategies are updated until June 2020.

Environmental risk assessment of pharmaceuticals at a seasonal holiday destination in the largest freshwater shallow lake in Central Europe.

The presence of pharmacologically active compounds (PhACs) in surface waters poses an environmental risk of chronic exposure to nontarget organisms, which is a well-established and serious concern worldwide. Our aim was to determine the temporal changes in ecological risk quotient (RQ) based on the concentrations of 42 PhACs from six sampling sites on seven sampling dates in the water of a freshwater lake in Central Europe preferentially visited by tourists. Our hypothesis was that the environmental risk increases during the summer holiday season due to the influence of tourists. Different experimental toxicological threshold concentrations and seasonal measured environmental concentrations of 16 PhACs were applied to ecological risk assessment. RQs of 4 dominant PhACs (diclofenac, estrone [E1], estradiol [E2], and caffeine) indicated high ecological risk (RQ > 1) for freshwater ecosystems. Additionally, our results confirmed the assumptions that the high tourist season had a significant impact on the calculated RQ; however, these results are mainly due to the concentration and temporal change of particular PhACs, including diclofenac (5.3-419.4 ng/L), E1 (0.1-5.5 ng/L), and E2 (0.1-19.6 ng/L). The seasonal dependent highest RQs changed as follows: 9.80 (June 2017; E2), 1.23 (August 2017; E1), 0.43 (November 2017; E1), 0.51 (April 2018; E1), 5.58 (June 2018, diclofenac), 39.50 (August 2018; diclofenac), and 30.60 (October 2018; diclofenac).

Charge-assisted hydrogen bonding in salts of 2-amino-1H-benzimidazole with 3-phenylpropynoic acid and oct-2-ynoic acid.

The 100 K structures of two salts, namely 2-amino-1H-benzimidazolium 3-phenylpropynoate, C7H8N3(+)·C9H5O2(-), (I), and 2-amino-1H-benzimidazolium oct-2-ynoate, C7H8N3(+)·C8H11O2(-), (II), both have monoclinic symmetry (space group P21/c) and display N-H...O hydrogen bonding. Both structures show packing with corrugated sheets of hydrogen-bonded molecules lying parallel to the [001] direction. Two hydrogen-bonded ring motifs can be identified and described with graph sets R(2)(2)(8) and R(4)(4)(16), respectively, in both (I) and (II). Computational chemistry calculations performed on both compounds show that the hydrogen-bonded ion pairs are more energetically favourable in the crystal structure than their hydrogen-bonded neutral molecule counterparts.

Molecular formula analysis of fragment ions by isotope-selective collision-induced dissociation tandem mass spectrometry of pharmacologically active compounds.

The purpose of this work is to explore the mass fragment characterization of commonly used drugs through a novel approach, which involves isotope-selective tandem mass spectrometry (MS/MS). Collision-induced dissociation (CID) was performed with a low-resolution linear ion trap mass spectrometer in positive electrospray ionization. Three pharmacologically active ingredients, i.e. omeprazole, meloxicam and brinzolamide, selected as model compounds in their own formulation, were investigated as a sodiated adduct [C17 H19 N3 O3 S + Na](+) (omeprazole) and as protonated adducts, [C14 H13 N3 O4 S2 + H](+) and [C12 H21 N3 O5 S3 + H](+) , meloxicam and brinzolamide, respectively. Selecting a narrow window of ±0.5 m/z units, precursor ion fragmentation by CID-MS/MS of isotopologues A + 0, A + 1 and A + 2 was found very useful to confirm the chemical formula of product ions, thus aiding the establishment of characteristic fragmentation pathways of all three examined compounds. The correctness of putative molecular formula of product ions was easily demonstrated by exploiting the isotope peak abundance ratios (i.e. IF+0 /IF+1 and IF+0 /IF+2 ) as simple constraints in low-resolution MS instrumentations.