Synthesis, In Vivo Anticonvulsant Activity Evaluation and In Silico Studies of Some Quinazolin-4(3H)-One Derivatives.

Two series, "a" and "b", each consisting of nine chemical compounds, with 2,3-disubstituted quinazolin-4(3H)-one scaffold, were synthesized and evaluated for their anticonvulsant activity. They were investigated as dual potential positive allosteric modulators of the GABAA receptor at the benzodiazepine binding site and inhibitors of carbonic anhydrase II. Quinazolin-4(3H)-one derivatives were evaluated in vivo (D1-3 = 50, 100, 150 mg/kg, administered intraperitoneally) using the pentylenetetrazole (PTZ)-induced seizure model in mice, with phenobarbital and diazepam, as reference anticonvulsant agents. The in silico studies suggested the compounds act as anticonvulsants by binding on the allosteric site of GABAA receptor and not by inhibiting the carbonic anhydrase II, because the ligands-carbonic anhydrase II predicted complexes were unstable in the molecular dynamics simulations. The mechanism targeting GABAA receptor was confirmed through the in vivo flumazenil antagonism assay. The pentylenetetrazole experimental anticonvulsant model indicated that the tested compounds, 1a-9a and 1b-9b, present a potential anticonvulsant activity. The evaluation, considering the percentage of protection against PTZ, latency until the onset of the first seizure, and reduction in the number of seizures, revealed more favorable results for the "b" series, particularly for compound 8b.

Discovery of New Hydrazone-Thiazole Polyphenolic Antioxidants through Computer-Aided Design and In Vitro Experimental Validation.

Oxidative stress is linked to a series of diseases; therefore, the development of efficient antioxidants might be beneficial in preventing or ameliorating these conditions. Based on the structure of a previously reported compound with good antioxidant properties and on computational studies, we designed several catechol derivatives with enhanced antioxidant potential. The compounds were synthesized and physicochemically characterized, and their antioxidant activity was assessed through different antiradical, electron transfer and metal ions chelation assays, their electrochemical behavior and cytotoxicity were studied. The results obtained in the in vitro experiments correlated very well with the in silico studies; all final compounds presented very good antioxidant properties, generally superior to those of the reference compounds used. Similarly, the results obtained from studying the compounds' electrochemical behavior were in good agreement with the results of the antioxidant activity evaluation assays. Regarding the compounds' cytotoxicity, compound 7b had a dose-dependent inhibitory effect against all cell lines. In conclusion, through computer-aided design, we developed several catechol thiazolyl-hydrazones with excellent antioxidant properties, of which compound 7b, with two catechol moieties in its structure, exhibited the best antioxidant activity.

Application of fuzzy algorithms in conjunction with 1 H-NMR spectroscopy to differentiate alcoholic beverages.

BACKGROUND: Recent statistics from the European Commission indicate that wine is one of the commodities most commonly subject to food fraud. In this context, the development of reliable classification models to differentiate alcoholic beverages requires, besides sensitive analytical tools, the use of the most suitable data-processing methods like those based on advanced statistical tools or artificial intelligence. RESULTS: The present study aims to establish a new, innovative approach for the differentiation of alcoholic beverages (wines and fruit distillates), which is able to increase the discrimination rate of the models that have been developed. A data dimensionality reduction step was applied to proton nuclear magnetic resonance (1 H-NMR) profiles. This stage consisted of the application of fuzzy principal component analysis (FPCA) prior to the development of classification models through discriminant analysis. The enhancement of the model's classification potential by the application of FPCA in comparison with principal component analysis (PCA) was discussed. CONCLUSION: The association of 1 H-NMR spectroscopy and an appropriate statistical approach provided a very effective tool for the differentiation of alcoholic beverages. To develop reliable metabolomic approaches for the differentiation of wines and fruit distillates, 1 H-NMR spectroscopic data were exploited in conjunction with fuzzy algorithms to reduce data dimensionality. The study proved the greater efficiency of using FPCA scores in comparison with those obtained through the widely applied PCA. The proposed approach enabled wines to be distinguished perfectly according to their geographical origins, cultivar, and vintage, and this could be used for wine classification. Moreover, 100% correctly classified samples were also achieved for the botanical and geographical differentiation of fruit distillates. © 2022 Society of Chemical Industry.

Synthesis of New Phenolic Derivatives of Quinazolin-4(3H)-One as Potential Antioxidant Agents-In Vitro Evaluation and Quantum Studies.

Considering the important damage caused by the reactive oxygen (ROS) and nitrogen (RNS) species in the human organism, the need for new therapeutic agents, with superior efficacy to the known natural and synthetic antioxidants, is crucial. Quinazolin-4-ones are known for their wide range of biological activities, and phenolic compounds display an important antioxidant effect. Linking the two active pharmacophores may lead to an increase of the antioxidant activity. Therefore, we synthesized four series of new hybrid molecules bearing the quinazolin-4-one and phenol scaffolds. Their antioxidant potential was evaluated in vitro, considering different possible mechanisms of action: hydrogen atom transfer, ability to donate electrons and metal ions chelation. Theoretical quantum and thermodynamical calculations were also performed. Some compounds, especially the ortho diphenolic ones, exerted a stronger antioxidant effect than ascorbic acid and Trolox.

Novel 2,4-Disubstituted-1,3-Thiazole Derivatives: Synthesis, Anti-Candida Activity Evaluation and Interaction with Bovine Serum Albumine.

Herein we report the synthesis of two novel series of 1,3-thiazole derivatives having a lipophilic C4-substituent on account of the increasing need for novel and versatile antifungal drugs for the treatment of resistant Candida sp.-based infections. Following their structural characterization, the anti-Candida activity was evaluated in vitro while using the broth microdilution method. Three compounds exhibited lower Minimum Inhibitory Concentration (MIC) values when compared to fluconazole, being used as the reference antifungal drug. An in silico molecular docking study was subsequently carried out in order to gain more insight into the antifungal mechanism of action, while using lanosterol-C14α-demethylase as the target enzyme. Fluorescence microscopy was employed to further investigate the cellular target of the most promising molecule, with the obtained results confirming its damaging effect towards the fungal cell membrane integrity. Finally, the distribution and the pharmacological potential in vivo of the novel thiazole derivatives was investigated through the study of their binding interaction with bovine serum albumin, while using fluorescence spectroscopy.

New Phenolic Derivatives of Thiazolidine-2,4-dione with Antioxidant and Antiradical Properties: Synthesis, Characterization, In Vitro Evaluation, and Quantum Studies.

Oxidative stress has been incriminated in the physiopathology of many diseases, such as diabetes, cancer, atherosclerosis, and cardiovascular and neurodegenerative diseases. There is a great interest in developing new antioxidants that could be useful for preventing and treating conditions for which oxidative stress is suggested as the root cause. The thiazolidine-2,4-dione derivatives have been reported to possess various pharmacological activities and the phenol moiety is known as a pharmacophore in many naturally occurring and synthetic antioxidants. Twelve new phenolic derivatives of thiazolidine-2,4-dione were synthesized and physicochemically characterized. The antioxidant capacity of the synthesized compounds was assessed through several in vitro antiradical, electron transfer, and Fe2+ chelation assays. The top polyphenolic compounds 5f and 5l acted as potent antiradical and electron donors, with activity comparable to the reference antioxidants used. The ferrous ion chelation capacity of the newly synthesized compounds was modest. Several quantum descriptors were calculated in order to evaluate their influence on the antioxidant and antiradical properties of the compounds and the chemoselectivity of the radical generation reactions has been evaluated. The correlation with the energetic level of the frontier orbitals partially explained the antioxidant activity, whereas a better correlation was found while evaluating the O-H bond dissociation energy of the phenolic groups.

A Novel Series of Acylhydrazones as Potential Anti-Candida Agents: Design, Synthesis, Biological Evaluation and In Silico Studies.

In the context of an increased incidence of invasive fungal diseases, there is an imperative need of new antifungal drugs with improved activity and safety profiles. A novel series of acylhydrazones bearing a 1,4-phenylene-bisthiazole scaffold was designed based on an analysis of structures known to possess anti-Candida activity obtained from a literature review. Nine final compounds were synthesized and evaluated in vitro for their inhibitory activity against various strains of Candida spp. The anti-Candida activity assay revealed that some of the new compounds are as active as fluconazole against most of the tested strains. A molecular docking study was conducted in order to evaluate the binding poses towards lanosterol 14α-demethylase. An in silico ADMET analysis showed that the compounds possess drug-like properties and represent a biologically active framework that should be further optimized as potential hits.

Design and Synthesis of Novel 1,3-Thiazole and 2-Hydrazinyl-1,3-Thiazole Derivatives as Anti-Candida Agents: In Vitro Antifungal Screening, Molecular Docking Study, and Spectroscopic Investigation of their Binding Interaction with Bovine Serum Albumin.

In the context of there being a limited number of clinically approved drugs for the treatment of Candida sp.-based infections, along with the rapid development of resistance to the existing antifungals, two novel series of 4-phenyl-1,3-thiazole and 2-hydrazinyl-4-phenyl-1,3-thiazole derivatives were synthesized and tested in vitro for their anti-Candida potential. Two compounds (7a and 7e) showed promising inhibitory activity against the pathogenic C. albicans strain, exhibiting substantially lower MIC values (7.81 µg/mL and 3.9 µg/mL, respectively) as compared with the reference drug fluconazole (15.62 µg/mL). Their anti-Candida activity is also supported by molecular docking studies, using the fungal lanosterol C14α-demethylase as the target enzyme. The interaction of the most biologically active synthesized compound 7e with bovine serum albumin was investigated through fluorescence spectroscopy, and the obtained data suggested that this molecule might efficiently bind carrier proteins in vivo in order to reach the target site.

Design, Synthesis and Biological Evaluation of New Piperazin-4-yl-(acetyl-thiazolidine-2,4-dione) Norfloxacin Analogues as Antimicrobial Agents.

 In an effort to improve the antimicrobial activity of norfloxacin, a series of hybrid norfloxacin-thiazolidinedione molecules were synthesized and screened for their direct antimicrobial activity and their anti-biofilm properties. The new hybrids were intended to have a new binding mode to DNA gyrase, that will allow for a more potent antibacterial effect, and for activity against current quinolone-resistant bacterial strains. Moreover, the thiazolidinedione moiety aimed to include additional anti-pathogenicity by preventing biofilm formation. The resulting compounds showed promising direct activity against Gram-negative strains, and anti-biofilm activity against Gram-positive strains. Docking studies and ADMET were also used in order to explain the biological properties and revealed some potential advantages over the parent molecule norfloxacin.

New N-(oxazolylmethyl)-thiazolidinedione Active against Candida albicans Biofilm: Potential Als Proteins Inhibitors.

C. albicans is the most frequently occurring fungal pathogen, and is becoming an increasing public health problem, especially in the context of increased microbial resistance. This opportunistic pathogen is characterized by a versatility explained mainly by its ability to form complex biofilm structures that lead to enhanced virulence and antibiotic resistance. In this context, a review of the known C. albicans biofilm formation inhibitors were performed and a new N-(oxazolylmethyl)-thiazolidinedione scaffold was constructed. 16 new compounds were synthesized and characterized in order to confirm their proposed structures. A general antimicrobial screening against Gram-positive and Gram-negative bacteria, as well as fungi, was performed and revealed that the compounds do not have direct antimicrobial activity. The anti-biofilm activity evaluation confirmed the compounds act as selective inhibitors of C. albicans biofilm formation. In an effort to substantiate this biologic profile, we used in silico investigations which suggest that the compounds could act by binding, and thus obstructing the functions of, the C. albicans Als surface proteins, especially Als1, Als3, Als5 and Als6. Considering the well documented role of Als1 and Als3 in biofilm formation, our new class of compounds that target these proteins could represent a new approach in C. albicans infection prevention and management.

Design, Synthesis and Antifungal Activity Evaluation of New Thiazolin-4-ones as Potential Lanosterol 14α-Demethylase Inhibitors.

Twenty-three thiazolin-4-ones were synthesized starting from phenylthioamide or thiourea derivatives by condensation with α-monochloroacetic acid or ethyl α-bromoacetate, followed by substitution in position 5 with various arylidene moieties. All the synthesized compounds were physico-chemically characterized and the IR (infrared spectra), ¹H NMR (proton nuclear magnetic resonance), 13C NMR (carbon nuclear magnetic resonance) and MS (mass spectrometry) data were consistent with the assigned structures. The synthesized thiazolin-4-one derivatives were tested for antifungal properties against several strains of Candida and all compounds exhibited efficient anti-Candida activity, two of them (9b and 10) being over 500-fold more active than fluconazole. Furthermore, the compounds' lipophilicity was assessed and the compounds were subjected to in silico screening for prediction of their ADME-Tox properties (absorbtion, distribution, metabolism, excretion and toxicity). Molecular docking studies were performed to investigate the mode of action towards the fungal lanosterol 14α-demethylase, a cytochrome P450-dependent enzyme. The results of the in vitro antifungal activity screening, docking study and ADME-Tox prediction revealed that the synthesized compounds are potential anti-Candida agents that might act by inhibiting the fungal lanosterol 14α-demethylase and can be further optimized and developed as lead compounds.

New 2-Phenylthiazoles as Potential Sortase A Inhibitors: Synthesis, Biological Evaluation and Molecular Docking.

Sortase A inhibition is a well establish strategy for decreasing bacterial virulence by affecting numerous key processes that control biofilm formation, host cell entry, evasion and suppression of the immune response and acquisition of essential nutrients. A meta-analysis of structures known to act as Sortase A inhibitors provided the starting point for identifying a new potential scaffold. Based on this template a series of new potential Sortase A inhibitors, that contain the 2-phenylthiazole moiety, were synthesized. The physicochemical characterisation confirmed the identity of the proposed structures. Antibacterial activity evaluation showed that the new compounds have a reduced activity against bacterial cell viability. However, the compounds prevent biofilm formation at very low concentrations, especially in the case of E. faecalis. Molecular docking studies performed estimate that this is most likely due to the inhibition of Sortase A. The new compounds could be used as add-on therapies together with known antibacterial agents in order to combat multidrug-resistance enterococcal infections.

Fusing 1H NMR and Raman experimental data for the improvement of wine recognition models.

The present study proposes the development of new wine recognition models based on Artificial Intelligence (AI) applied to the mid-level data fusion of 1H NMR and Raman data. In this regard, a supervised machine learning method, namely Support Vector Machines (SVMs), was applied for classifying wine samples with respect to the cultivar, vintage, and geographical origin. Because the association between the two data sources generated an input space with a high dimensionality, a feature selection algorithm was employed to identify the most relevant discriminant markers for each wine classification criterion, before SVM modeling. The proposed data processing strategy allowed the classification of the wine sample set with accuracies up to 100% in both cross-validation and on an independent test set and highlighted the efficiency of 1H NMR and Raman data fusion as opposed to the use of a single-source data for differentiating wine concerning the cultivar and vintage.

Synthesis, characterization, and in vitro-in ovo toxicological screening of silibinin fatty acids conjugates as prodrugs with potential biomedical applications.

Silibinin (SIL), the most active phytocompound from Silybum marianum (L.), exerts many biological effects but has low stability and bioavailability. To overcome these drawbacks, the current research proposed the synthesis of silibilin oleate (SIL-O) and silibilin linoleate (SIL-L) derivatives as prodrugs with potentially optimized properties for biomedical applications, and the establishment of their in vitro-in ovo safety profiles. The physicochemical characterization of the obtained compounds using density functional theory (DFT) calculations, and Raman and 1H liquid-state nuclear magnetic resonance (NMR) spectroscopy confirmed the formation of SIL-O and SIL-L complexes. Computational predictions revealed that these lipophilic derivatives present a lower drug-likeness score (-29.96 for SIL-O and -23.55 for SIL-L) compared to SIL, but an overall positive drug score (0.07) and no risk for severe adverse effects. SIL-O and SIL-L showed no cytotoxicity or impairment in cell migration at low concentrations, but at the highest concentration (100 µM), they displayed distinct toxicological profiles. SIL-L was more cytotoxic (on cardiomyoblasts - H9c2(2-1), hepatocytes - HepaRG, and keratinocytes - HaCaT) than SIL-O or SIL, significantly inhibiting cell viability (<60%), altering cellular morphology, reducing cell confluence (<70%), and inducing prominent apoptotic-like nuclear features. At the concentration of 100 µM, SIL-O presented an irritation score (IS) of 0.61, indicating a lack of irritant effect on the chorioallantoic membrane (CAM), while SIL-L was classified as a slight irritant with an IS of 1.99. These findings outline a more favorable in vitro and in ovo biocompatibility for SIL-O compared to SIL L, whose applications are dosage limited due to potential toxicity.

Synthesis, Cytotoxicity and Antioxidant Activity Evaluation of Some Thiazolyl-Catechol Compounds.

A series of thiazolyl-catechol compounds with antioxidant and cytotoxic activities were synthesized by a Hantzsch heterocyclization, using diverse thioamides as the thiocarbonyl component and 4-chloroacetyl-catechol as haloketone. These compounds were characterized by MS, IR spectroscopy, and NMR. Their antioxidant potential was evaluated by antiradical, electron transfer, and ferrous ion chelation assays using ascorbic acid, Trolox, and EDTA-Na2 as references. The cytotoxicity of the synthesized compounds was evaluated on two different cell types, normal human foreskin fibroblasts (BJ) and human pulmonary malignant cells (A549), using gefitinib as a reference anticancer drug. The results obtained from the tests highlighted compounds 3g and 3h with significant antioxidant activities. The highest cytotoxic potency against A549 cells was exhibited by compounds 3i and 3j, while compound 3g demonstrated exceptional selectivity on malignant cells compared to gefitinib. These promising results encourage further investigation into targeted modifications on position 2 of the thiazole ring, in order to develop novel therapeutic agents.

Discovery of A Novel Series of Quinazoline-Thiazole Hybrids as Potential Antiproliferative and Anti-Angiogenic Agents.

Considering the pivotal role of angiogenesis in solid tumor progression, we developed a novel series of quinazoline-thiazole hybrids (SA01-SA07) as antiproliferative and anti-angiogenic agents. Four out of the seven compounds displayed superior antiproliferative activity (IC50 =1.83-4.24 µM) on HepG2 cells compared to sorafenib (IC50 = 6.28 µM). The affinity towards the VEGFR2 kinase domain was assessed through in silico prediction by molecular docking, molecular dynamics studies, and MM-PBSA. The series displayed a high degree of similarity to sorafenib regarding the binding pose within the active site of VEGFR2, with a different orientation of the 4-substituted-thiazole moieties in the allosteric pocket. Molecular dynamics and MM-PBSA evaluations identified SA05 as the hybrid forming the most stable complex with VEGFR2 compared to sorafenib. The impact of the compounds on vascular cell proliferation was assessed on EA.hy926 cells. Six compounds (SA01-SA05, SA07) displayed superior anti-proliferative activity (IC50 = 0.79-5.85 µM) compared to sorafenib (IC50 = 6.62 µM). The toxicity was evaluated on BJ cells. Further studies of the anti-angiogenic effect of the most promising compounds, SA04 and SA05, through the assessment of impact on EA.hy296 motility using a wound healing assay and in ovo potential in a CAM assay compared to sorafenib, led to the confirmation of the anti-angiogenic potential.

Inclusion of a Catechol-Derived Hydrazinyl-Thiazole (CHT) in ß-Cyclodextrin Nanocavity and Its Effect on Antioxidant Activity: A Calorimetric, Spectroscopic and Molecular Docking Approach.

The aim of the present research was to obtain a supramolecular complex between a strong antioxidant compound previously reported by our group, in order to extend its antioxidant activity. The formation of the inclusion complex of a catechol hydrazinyl-thiazole derivative (CHT) and ß-cyclodextrin in aqueous solution has been investigated using isothermal titration calorimetry (ITC), spectroscopic and theoretical methods. The stoichiometry of this inclusion complex was established to be equimolar (1:1) and its equilibrium constant was determined. An estimation of the thermodynamic parameters of the inclusion complex showed that it is an enthalpy and entropy-driven process. Our observations also show that hydrophobic interactions are the key interactions that prevail in the complex. 1H NMR spectroscopic method was employed to study the inclusion process in an aqueous solution. Job plots derived from the 1H NMR spectral data demonstrated 1:1 stoichiometry of the inclusion complex in a liquid state. A 2D NMR spectrum suggests the orientation of the aromatic ring of CHT inside the ß-CD cavity. The antiradical activity of the complex was evaluated and compared with free CHT, indicating a delayed activity compared with free CHT. To obtain additional qualitative and visual insight into the particularity of CHT and ß-CD interaction, molecular docking calculations have been performed.

Antioxidant Activity Evaluation and Assessment of the Binding Affinity to HSA of a New Catechol Hydrazinyl-Thiazole Derivative.

Polyphenols have attained pronounced attention due to their ability to provide numerous health benefits and prevent several chronic diseases. In this study, we designed, synthesized and analyzed a water-soluble molecule presenting a good antioxidant activity, namely catechol hydrazinyl-thiazole (CHT). This molecule contains 3',4'-dihydroxyphenyl and 2-hydrazinyl-4-methyl-thiazole moieties linked through a hydrazone group with very good antioxidant activity in the in vitro evaluations performed. A preliminary validation of the CHT developing hypothesis was performed evaluating in silico the bond dissociation enthalpy (BDE) of the phenol O-H bonds, compared to our previous findings in the compounds previously reported by our group. In this paper, we report the binding mechanism of CHT to human serum albumin (HSA) using biophysical methods in combination with computational studies. ITC experiments reveal that the dominant forces in the binding mechanism are involved in the hydrogen bond or van der Waals interactions and that the binding was an enthalpy-driven process. NMR relaxation measurements were applied to study the CHT-protein interaction by changing the drug concentration in the solution. A molecular docking study added an additional insight to the experimental ITC and NMR analysis regarding the binding conformation of CHT to HSA.

Antioxidant and Cytotoxic Activity of New Polyphenolic Derivatives of Quinazolin-4(3H)-one: Synthesis and In Vitro Activities Evaluation.

The development of hybrid molecules with significant human therapeutic properties is one of the main approaches of pharmaceutical research. One of the most important pharmacophores is the quinazolin-4(3H)-one heterocycle moiety, due to its wide range of biological activities. By its derivatization with polyphenolic compounds, in our previous research, it proved to possess a good antiradical activity of ortho-diphenolic derivatives of quinazolin-4(3H)-one. In this study, we developed two new series of compounds, with an additional phenolic group or with a methyl group on the thioacetohydrazone fragment. The methods used to evaluate the activity of the compounds were radical scavenging, reduction of oxidizing reagents and transition metals' ions chelation assays. Quantum descriptors were also calculated in order to evaluate the influence of substituents and their position on the activity of the compounds. The cytotoxic activity was evaluated using normal human foreskin fibroblast cells (BJ) and two cancerous cell lines, lung adenocarcinoma cells (A549) and prostate carcinoma cells (LNCaP). The results obtained for the pyrogallol derivatives showed a high antioxidant activity compared to ascorbic acid and Trolox. All the synthesized compounds displayed a higher cytotoxicity against the cancerous cell types and a high cytocompatibility with the normal cells. The antioxidant activity was deeply influenced by the addition of the third phenolic group in the synthesized molecules.

Authentication of Transylvanian Spirits Based on Isotope and Elemental Signatures in Conjunction with Statistical Methods.

The potential association between stable isotope ratios of light elements and mineral content, in conjunction with unsupervised and supervised statistical methods, for differentiation of spirits, with respect to some previously defined criteria, is reviewed in this work. Thus, based on linear discriminant analysis (LDA), it was possible to differentiate the geographical origin of distillates in a percentage of 96.2% for the initial validation, and the cross-validation step of the method returned 84.6% of correctly classified samples. An excellent separation was also obtained for the differentiation of spirits producers, 100% in initial classification, and 95.7% in cross-validation, respectively. For the varietal recognition, the best differentiation was achieved for apricot and pear distillates, a 100% discrimination being obtained in both classifications (initial and cross-validation). Good classification percentages were also obtained for plum and apple distillates, where models with 88.2% and 82.4% in initial and cross-validation, respectively, were achieved for plum differentiation. A similar value in the cross-validation procedure was reached for the apple spirits. The lowest classification percent was obtained for quince distillates (76.5% in initial classification followed by 70.4% in cross-validation). Our results have high practical importance, especially for trademark recognition, taking into account that fruit distillates are high-value commodities; therefore, the temptation of "fraud", i.e., by passing regular distillates as branded ones, could occur.