A simple UHPLC-MS/MS method for determination of SET2, a selective antagonist of TRPV2 receptor, in rat plasma samples.

Targeting the transient receptor potential vanilloid 2 channels (TRPV2) in order to alleviate or reverse the course of several diseases including multiple cancers, cardiovascular, immunological, or neurological disorders have been a matter of focus for several years now. SET2, a selective TRPV2 inhibitor, represents an innovative molecule which came into recognition in 2019 and seems to be a promising therapeutic modality in cancer and cardiac diseases. Drug discovery and bioanalysis in clinical environment demands simple, excellent, highly reliable, fast, sensitive, and selective analytical approaches which enable unambiguous identification and quantification of demanded molecule. Here, a targeted ultra-high-performance liquid chromatography - tandem mass spectrometry with electrospray ionization was developed for the quantification of SET2 in plasma samples. The developed method enabled analysis of approx. 15 samples within one hour. Simplicity of the whole analytical procedure can be emphasized by a very simple sample pretreatment based only on the protein precipitation with organic acid (here, 2 M tricholoroacetic acid). The validation procedure was characterized by promising validation parameters and excellent sensitivity what was documented by the limit of detection value at pg.mL-1 concentration level. Analytical validation reported intra- and interday accuracy < 15 % for all quality control samples concentration levels. Similarly, excellent level of intra- (0.1 - 4.8 %) and interday (0.5 - 3.3 %) precision for the tested quality control samples was obtained. The applicability of the developed method was proven by quantifying SET2 concentration levels in plasma samples obtained from Wistar rats that were administered this drug intraperitoneally at a dose of 25 mg/kg. We expect that our new analytical method represents a very attractive tool that could be easily implemented in pharmacokinetics studies and/or therapeutic drug monitoring. Moreover, its applicability was confirmed by the new practicability evaluation metric tool.

Novel 1,3,5-Triazinyl Aminobenzenesulfonamides Incorporating Aminoalcohol, Aminochalcone and Aminostilbene Structural Motifs as Potent Anti-VRE Agents, and Carbonic Anhydrases I, II, VII, IX, and XII Inhibitors.

A series of 1,3,5-triazinyl aminobenzenesulfonamides substituted by aminoalcohol, aminostilbene, and aminochalcone structural motifs was synthesized as potential human carbonic anhydrase (hCA) inhibitors. The compounds were evaluated on their inhibition of tumor-associated hCA IX and hCA XII, hCA VII isoenzyme present in the brain, and physiologically important hCA I and hCA II. While the test compounds had only a negligible effect on physiologically important isoenzymes, many of the studied compounds significantly affected the hCA IX isoenzyme. Several compounds showed activity against hCA XII; (E)-4-{2-[(4-[(2,3-dihydroxypropyl)amino]-6-[(4-styrylphenyl)amino]-1,3,5-triazin-2-yl)amino]ethyl}benzenesulfonamide (31) and (E)-4-{2-[(4-[(4-hydroxyphenyl)amino]-6-[(4-styrylphenyl)amino]-1,3,5-triazin-2-yl)amino]ethyl}benzenesulfonamide (32) were the most effective inhibitors with KIs = 4.4 and 5.9 nM, respectively. In addition, the compounds were tested against vancomycin-resistant Enterococcus faecalis (VRE) isolates. (E)-4-[2-({4-[(4-cinnamoylphenyl)amino]-6-[(4-hydroxyphenyl)amino]-1,3,5-triazin-2-yl}amino)ethyl]benzenesulfonamide (21) (MIC = 26.33 µM) and derivative 32 (MIC range 13.80-55.20 µM) demonstrated the highest activity against all tested strains. The most active compounds were evaluated for their cytotoxicity against the Human Colorectal Tumor Cell Line (HCT116 p53 +/+). Only 4,4'-[(6-chloro-1,3,5-triazin-2,4-diyl)bis(iminomethylene)]dibenzenesulfonamide (7) and compound 32 demonstrated an IC50 of ca. 6.5 µM; otherwise, the other selected derivatives did not show toxicity at concentrations up to 50 µM. The molecular modeling and docking of active compounds into various hCA isoenzymes, including bacterial carbonic anhydrase, specifically α-CA present in VRE, was performed to try to outline a possible mechanism of selective anti-VRE activity.

Enantioseparation of citalopram enantiomers by capillary electrophoresis: Method development through experimental design and computational modeling.

Citalopram (CIT) is a frequently used modern antidepressant that inhibits selectively serotonin reuptake in the brain. It has a chiral center in its structure and is used in therapy as both racemic mixture and pure enantiomer as its pharmacological effect is almost entirely associated with S-CIT. The aim of this study was the development of a simple and rapid capillary electrophoresis (CE) method for the separation and quantification of CIT enantiomers. To establish the optimum chiral selector, several native and derivatized, neutral, and ionized cyclodextrins (CDs) were examined at different pH levels. An experimental design strategy was adopted for method optimization; a fractional factorial design was applied for screening purposes to identify significant experimental factors followed by a face-centered central composite design used for optimization purposes. Computational modeling was used to obtain information on the interaction energy and the geometry of the complexes to aid in the understanding of chiral separation mechanism. The best results were obtained when using a 25-mM phosphate buffer at pH 7.0, 3-mM CM-ß-CD as chiral selector, 17.5°C temperature, 15-kV voltage, and 50 mbar/s hydrodynamic injection. The separation time was fast, below 3 min, and the migration order was S-CIT followed by R-CIT. The analytical performance of the method was verified in terms of precision, linearity, accuracy, sensibility, and robustness, and the method was applied for the determination of CIT enantiomers from pharmaceutical preparations.

Photoswitching hydrazones based on benzoylpyridine.

The photoswitching properties of three readily accesible benzoylpyridine hydrazones were investigated. Interestingly, replacing classical stirring with ultrasound wave activation results in pure thermodynamically less stable E isomer crystallization at room temperature. The studied benzoylpyridine hydrazones exhibit both P- and T-photochromic behaviour, depending on the benzoyl substituent, and improved addressability compared to most of the previously published pyridyl based hydrazones and 2-pyridylcarboxaldehyde acylhydrazones. Low activation entropy and calculated transition state geometry favour the inversion mechanism of their thermal isomerization rather than tautomerization followed by rotation recently found for pyridyl-hydrazone ester or nitrile rotary switches. The association behaviour of the nitro derivative during its thermal E-to-Z isomerization in highly polar DMSO indicates an important role of intermolecular hydrogen bonding in the thermal kinetics of benzoylpyridine-based hydrazone photoswitches. Moreover, the addition of triethylamine significantly accelerates the rate of Z-isomer thermal isomerization from days to seconds and could thus pave the way to fast pyridyl hydrazone T-type photochromic compounds in polar solvents. This study could therefore contribute to general knowledge related to the photochromic behaviour of hydrazones as an important class of modern photoswitches.

Novel sulfonamides incorporating 1,3,5-triazine and amino acid structural motifs as inhibitors of the physiological carbonic anhydrase isozymes I, II and IV and tumor-associated isozyme IX.

A new series of thirty s-triazinyl-substituted aminoalkylbenzenesulfonamides, incorporating a symmetric pair of amino acid moieties, is reported, together with inhibition studies of physiologically relevant human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms. Specifically, against the cytosolic hCA I, II, transmembrane hCA IV and the tumor-associated, membrane-bound hCA IX. The compounds were prepared by nucleophilic substitution of chlorine atoms from cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) using environmentally friendly water-based synthetic conditions. The products yields ranged in the interval of 43-97%. Purity of the products was verified by the HPLC-DAD-ESI-Q-TOF MS method. Identity of the products was confirmed by the same method plus NMR and IR. The products showed weak inhibition of the cytosolic, off-target isozyme hCA II, but some of them were low nanomolar (i.e. strong) inhibitors of the tumor-associated hCA IX. The series offered representatives selective towards isozymes hCA I, IV and IX. 2,2'-((6-((4-sulfamoylphenethyl)amino)-1,3,5-triazine-2,4-diyl)bis(imino))disuccinic acid demonstrated highest selectivity to the tumor-associated isoform hCA IX over off-target isozymes, with impressive KI ratio (hCA II/hCA IX) 213.9 and inhibition constant equal to acetazolamide (KI = 25.8 nM). Although the selectivities of some other products, e.g. those conjugating Leu and Glu, were a bit lower (188.7 and 84.3, respectively) their inhibition constants were similar to acetazolamide too (24.0 and 27.1, respectively). The selected most impressive results from the inhibition study were interpreted via molecular modeling experiment (docking in Glide) revealing different inter-molecular enzyme-substrate interaction of 2,2'-((6-((4-sulfamoylphenethyl)amino)-1,3,5-triazine-2,4-diyl)bis(imino))disuccinic acid within specific hCA IX and hCA II microregions. Therefore, several selected compounds from this study can be considered as highly effective and selective inhibitors of hCA IX, worthy to further (preclinical) investigation.

Novel sulfonamide incorporating piperazine, aminoalcohol and 1,3,5-triazine structural motifs with carbonic anhydrase I, II and IX inhibitory action.

A new series of s-triazine derivatives incorporating sulfanilamide, homosulfanilamide, 4-aminoethyl-benzenesulfonamide and piperazine or aminoalcohol structural motifs is reported. Molecular docking was exploited to select compounds from virtual combinatorial library for synthesis and subsequent biological evaluation. The compounds were prepared by using step by step nucleophilic substitution of chlorine atoms from cyanuric chloride (2,4,6-trichloro-1,3,5-triazine). The compounds were tested as inhibitors of physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms. Specifically, against the cytosolic hCA I, II and tumor-associated hCA IX. These compounds show appreciable inhibition. hCA I was inhibited with KIs in the range of 8.5-2679.1 nM, hCA II with KIs in the range of 4.8-380.5 nM and hCA IX with KIs in the range of 0.4-307.7 nM. As other similar derivatives, some of the compounds showed good or excellent selectivity ratios for inhibiting hCA IX over hCA II, of 3.5-18.5. 4-[({4-Chloro-6-[(4-hydroxyphenyl)amino]-1,3,5-triazin-2-yl}amino)methyl] benzene sulfonamide demonstrated subnanomolar affinity for hCA IX (0.4 nM) and selectivity (18.50) over the cytosolic isoforms. This series of compounds may be of interest for the development of new, unconventional anticancer drugs targeting hypoxia-induced CA isoforms such as CA IX.

Optimization and Comparison of Synthetic Procedures for a Group of Triazinyl-Substituted Benzene-Sulfonamide Conjugates with Amino Acids.

Sulfonamides incorporating 1,3,5-triazine moieties can selectively and potently inhibit carbonic anhydrase transmembrane isoforms IX, XII, and XIV over cytosolic isoforms I and II. In the present work, a highly effective synthetic procedure was proposed for this group of potent cancerostatic drugs and compared with previously used methods. The synthesis of triazinyl-substituted benzene-sulfonamide conjugates with amino acids can be easily carried out using sodium carbonate-based water solution as a synthetic medium instead of N,N-Diisopropylethylamine/Dimethylformamide. The benefits of this synthetic procedure include: (i) high selectivity of the creation of disubstituted conjugates; (ii) several times higher yield (≥95%) than that achieved previously; (iii) elimination of organic solvents by the use of an environmental friendly water medium (green chemistry); (iv) simple and fast isolation of the product. The synthesis and resulting products were evaluated using TLC, IR, NMR, and MS methods. The present work demonstrates a significant advantage in providing shortened routes to target structures.

7-Dialkylaminocoumarin Oximates: Small Molecule Fluorescent "Turn-On" Chemosensors for Low-Level Water Content in Aprotic Organic Solvents.

The water sensing properties of two efficient two-component fluorescent "turn-on" chemo-sensors based on the 7-dialkylaminocoumarin oxime acid-base equilibrium were investigated. Interestingly, although simple frontier orbital analysis predicts an intramolecular photoinduced electron transfer quenching pathway in conjugated oximates, TD-DFT (Time-dependent density functional theory) quantum chemical calculations support non-radiative dark S1 excited state deactivation as a fluorescence quenching mechanism. Due to the acid-base sensing mechanism and sensitive "turn-on" fluorescent response, both studied coumarin aldoxime chemosensors exhibit rapid response to low-level water content in polar aprotic solvents, with detection limits comparable to chemodosimeters or chemosensors based on interpolymer π-stacking aggregation.

Synthesis and Antimicrobial Evaluation of 6-Alkylamino-N-phenylpyrazine-2-carboxamides.

This work presents synthesis and antimicrobial evaluation of nineteen 6-alkylamino-N-phenylpyrazine-2-carboxamides. Antimycobacterial activity was determined against Mycobacterium tuberculosis H37Rv, M. kansasii and two strains of M. avium. Generally, the antimycobacterial activity increased with prolongation of simple alkyl chain and culminated in compounds with heptylamino substitution (3e, 4e) with MIC = 5-10 µm against M. tuberculosis H37Rv. On the contrary, derivatives with modified alkyl chain (containing e.g. terminal methoxy or hydroxy group) as well as phenylalkylamino derivatives were mainly inactive. The most active compounds (with hexyl to octylamino substitution) were evaluated for their in vitro activity against drug-resistant strains of M. tuberculosis and possessed activity comparable to that of the reference drug isoniazid. None of the tested compounds were active against M. avium. Some derivatives exhibited activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (best MIC = 7.8 µm), while Gram-negative strains as well as tested fungal strains were completely unsusceptible. Active compounds were tested for in vitro toxicity on various cell lines and in most cases were non-toxic up to 100 µm.

Synthesis and antimycobacterial evaluation of 5-alkylamino-N-phenylpyrazine-2-carboxamides.

Substitution of chlorine in 5-chloro-N-phenylpyrazine-2-carboxamide (1) with simple n-alkylamines yielded a series of 5-alkylamino-N-phenylpyrazine-2-carboxamides (propylamino to octylamino derivatives), which possessed similar or increased activity against Mycobacterium tuberculosis H37Rv compared to parent 5-chloro derivative (1), with MIC ranging from 2.5 to 12.2 µM. 5-Butylamino to 5-heptylamino derivatives exerted similar activity also against Mycobacterium kansasii. Importantly, the substitution led also to significant decrease of in vitro cytotoxicity in HepG2 cell line. 5-Heptylamino-N-phenylpyrazine-2-carboxamide (1e) exerted MIC=2.5 µM (M.tbc) and IC50 >250 µM (HepG2). Further modification of alkylamino chain with terminal methoxy or hydroxy group lead to compounds with decreased or none activity, the decrease was proportional to the decrease of lipophilicity. 5-(2-Phenylethylamino) and 5-(3-phenylpropylamino) derivatives were also of decreased activity. On contrary to alkylamino derivatives derived from 1, alkylamino derivatives derived from 5-chloro-N-2-chlorophenylpyrazine-2-carboxamide (2) possessed substantially decreased or none activity. None of the prepared compounds was active against Mycobacterium avium.

Optimal detection of cholinesterase activity in biological samples: modifications to the standard Ellman's assay.

Ellman's assay is the most commonly used method to measure cholinesterase activity. It is cheap, fast, and reliable, but it has limitations when used for biological samples. The problems arise from 5,5-dithiobis(2-nitrobenzoic acid) (DTNB), which is unstable, interacts with free sulfhydryl groups in the sample, and may affect cholinesterase activity. We report that DTNB is more stable in 0.09 M Hepes with 0.05 M sodium phosphate buffer than in 0.1M sodium phosphate buffer, thereby notably reducing background. Using enzyme-linked immunosorbent assay (ELISA) to enrich tissue homogenates for cholinesterase while depleting the sample of sulfhydryl groups eliminates unwanted interactions with DTNB, making it possible to measure low cholinesterase activity in biological samples. To eliminate possible interference of DTNB with enzyme hydrolysis, we introduce a modification of the standard Ellman's assay. First, thioesters are hydrolyzed by cholinesterase to produce thiocholine in the absence of DTNB. Then, the reaction is stopped by a cholinesterase inhibitor and the produced thiocholine is revealed by DTNB and quantified at 412 nm. Indeed, this modification of Ellman's method increases butyrylcholinesterase activity by 20 to 25%. Moreover, high stability of thiocholine enables separation of the two reactions of the Ellman's method into two successive steps that may be convenient for some applications.

Isatinphenylsemicarbazones as efficient colorimetric sensors for fluoride and acetate anions - anions induce tautomerism.

The anion induced tautomerism of isatin-3-4-phenyl(semicarbazone) derivatives is studied herein. The interaction of F(-), AcO(-), H2PO4(-), Br(-) or HSO4(-) anions with E and Z isomers of isatin-3-4-phenyl(semicarbazone) and N-methylisatin-3-4-phenyl(semicarbazone) as sensors influences the tautomeric equilibrium of these sensors in the liquid phase. This tautomeric equilibrium is affected by (1) the inter- and intra-molecular interactions' modulation of isatinphenylsemicarbazone molecules due to the anion induced change in the solvation shell of receptor molecules and (2) the sensor-anion interaction with the urea hydrogens. The acid-base properties of anions and the difference in sensor structure influence the equilibrium ratio of the individual tautomeric forms. Here, the tautomeric equilibrium changes were indicated by "naked-eye" experiment, UV-VIS spectral and (1)H NMR titration, resulting in confirmation that appropriate selection of experimental conditions leads to a high degree of sensor selectivity for some investigated anions. Sensors' E and Z isomers differ in sensitivity, selectivity and sensing mechanism. Detection of F(-) or CH3COO(-) anions at high weakly basic anions' excess is possible.

The inhibitory potency of local anesthetics on NMDA receptor signalling depends on their structural features.

Development of postoperative hyperalgesia depends on N-methyl-d-aspartate (NMDA) receptor activation. Local anesthetics protect against those hyperalgesic pain states and inhibit NMDA receptor activation. To outline what structural features of local anesthetics are responsible for NMDA receptor inhibition we evaluated a series of experimental lidocaine analogs (carbanilic derivates). Human GluN1/GluN2A NMDA receptors were expressed recombinantly in Xenopus laevis oocytes. Peak currents were measured by voltage clamp technique. Oocytes were stimulated with glutamate/glycine (EC(50)). The responses following a 10min incubation with in total 13 experimental derivates of local anesthetics (10(-3)M-10(-7)M) were measured to obtain the IC(50). Furthermore the Comprehensive Descriptors for Structural and Statistical Analysis CODESSA software was used to design a Quantitative Structure-Activity Relationship (QSAR)-model for all substances. The IC(50) values were in the range of 2.74×10(-5)M-2.26×10(-3)M, strongly affected by the position and the length of the aliphatic side chain in the aromatic part of the local anesthetic molecule. Substance with no substituent on the aromatic ring showed the highest inhibitory activity. The obtained QSAR model predicted that lidocaine derivatives with free positions 2 and 6 on the aromatic ring had a higher efficacy than clinically used local anesthetics for inhibition of NMDA receptor signaling. Structural changes of local anesthetic molecules can alter the potency to inhibit NMDA receptor signaling and are independent of the local anesthetic (sodium-channel blocking) potency. The development of novel drugs based on local anesthetic like structures may be a new approach for the protection or treatment of NMDA receptor mediated hyperalgesia and may be associated with a low side effect profile.

Sulfonamides incorporating 1,3,5-triazine moieties selectively and potently inhibit carbonic anhydrase transmembrane isoforms IX, XII and XIV over cytosolic isoforms I and II: Solution and X-ray crystallographic studies.

Reaction of cyanuryl chloride with d,l-amino acids and amino alcohols afforded a new series of triazinyl-substituted benzenesulfonamides incorporating amino acyl/hydroxyalkyl-amino moieties. Inhibition studies of physiologically relevant human carbonic anhydrase (CA, EC 4.2.1.1) isoforms, such as CA I, II, IX, XII and XIV with these compounds are reported. They showed moderate-weak inhibition of the cytosolic, offtarget isozymes CA I and II, but many of them were low nanomolar inhibitors of the transmembrane, tumor-associated CA IX and XII (and also of CA XIV). The X-ray crystal structure of two of these compounds in adduct with CA II allowed us to understand the features associated with this strong inhibitory properties and possibly also their selectivity. Two of these compounds were also investigated for the inhibition of other human isoforms, that is, hCA IV, VA, VB, VI, VII and XIII, as well as inhibitors of the fungal pathogenic CAs Nce103 (Candida albicans) and Can2 (Cryptococcus neoformans), showing interesting activity. The 1,3,5-triazinyl-substituted benzenesulfonamides constitute thus a class of compounds with great potential for obtaining inhibitors targeting both α-class mammalian, tumor-associated, and ß-class from pathogenic organisms CAs.

Carbonic anhydrase inhibitors: novel sulfonamides incorporating 1,3,5-triazine moieties as inhibitors of the cytosolic and tumour-associated carbonic anhydrase isozymes I, II and IX.

A new series of aromatic benzenesulfonamides incorporating 1,3,5-triazine moieties in their molecules is reported. This series was obtained by reaction of cyanuric chloride with sulfanilamide, homosulfanilamide or 4-aminoethylbenzenesulfonamide. The prepared dichlorotriazinyl-benzenesulfonamides were subsequently derivatized by reacting them with various nucleophiles, such as ammonia, hydrazine, primary and secondary amines, amino acid derivatives or phenol. The library of sulfonamides incorporating triazinyl moieties was tested for the inhibition of three physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isozymes, the cytosolic hCA I and II, and the transmembrane, tumour-associated hCA IX. The new compounds inhibited hCA I with inhibition constants in the range of 31-8500 nM, hCA II with inhibition constants in the range of 14-765 nM and hCA IX with inhibition constants in the range of 1.0-640 nM. Structure-activity relationship was straightforward and rather simple in this class of CA inhibitors, with the compounds incorporating compact moieties at the triazine ring (such as amino, hydrazino, ethylamino, dimethylamino or amino acyl) being the most active ones, and the derivatives incorporating such bulky moieties (n-propyl, n-butyl, diethylaminoethyl, piperazinylethyl, pyridoxal amine or phenoxy) being less effective hCA I, II and IX inhibitors. Some of the new derivatives also showed selectivity for inhibition of hCA IX over hCA II (selectivity ratios of 23.33-32.00), thus constituting excellent leads for the development of novel approaches for the management of hypoxic tumours.

Carbonic anhydrase inhibitors: synthesis and inhibition of cytosolic/tumor-associated carbonic anhydrase isozymes I, II, and IX with sulfonamides incorporating 1,2,4-triazine moieties.

A series of benzenesulfonamide derivatives incorporating triazine moieties in their molecules was obtained by reaction of cyanuric chloride with sulfanilamide, homosulfanilamide, or 4-aminoethylbenzenesulfonamide. The dichlorotriazinyl-benzenesulfonamides intermediates were subsequently derivatized by reaction with various nucleophiles, such as water, methylamine, or aliphatic alcohols (methanol and ethanol). The library of sulfonamides incorporating triazinyl moieties was tested for the inhibition of three physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isozymes, the cytosolic hCA I and II, and the transmembrane, tumor-associated hCA IX. The new compounds reported here inhibited hCA I with K(I)s in the range of 75-136nM, hCA II with K(I)s in the range of 13-278nM, and hCA IX with K(I)s in the range of 0.12-549nM. The first hCA IX-selective inhibitors were thus detected, as the chlorotriazinyl-sulfanilamide and the bis-ethoxytriazinyl derivatives of sulfanilamide/homosulfanilamide showed selectivity ratios for CA IX over CA II inhibition in the range of 166-706. Furthermore, some of these compounds have subnanomolar affinity for hCA IX, with K(I)s in the range 0.12-0.34nM. These derivatives are interesting candidates for the development of novel unconventional anticancer strategies targeting the hypoxic areas of tumors. Clear renal cell carcinoma, which is the most lethal urologic malignancy and is both characterized by very high CA IX expression and chemotherapy unresponsiveness, could be the leading candidate of such novel therapies.