Urolithin A and B Derivatives as ON-OFF Selective Fluorescent Sensors for Iron(III).

The detection and sensing of environmentally crucial metal ions has always been of great significance in various fields such as biological and environmental cycles. Our previous studies have indicated a new coumarin based lactone, Urolithin B (i.e., 3-Hydroxy[c]chromen-6-one) as a potent fluorescent probe for the selective detection of Iron (III). In order to question the extension of this application to other urolithins, we have synthesized the major urolithins that humans are exposed to through regular diet. Following the structure identifying studies, the compounds were tested in fluorescence titration to investigate their interaction with various metals. The results have indicated that each title compound is selective to interact with Iron (III) in ON-OFF mode, independent from the presence of another metal. Similar to the previous findings, the Job's plots displaying the ratio of complex formation 3:2 UROs:Fe3+ have indicated the significance of the lactone group solely.

Synthesis, Characterization, Molecular Docking, and Biological Activities of Some Natural and Synthetic Urolithin Analogs.

Urolithins (that is, hydroxy substituted benzo[c]chromen-6-one derivatives) are formed within the gastrointestinal tract following to the exposure to various ellagitannin rich diet, particularly involving pomegranate, nuts, and berries. Regarding the bioavailability deficiency of ellagitannins, the biological activities obtained through the extracts of these dietaries are attributed to the urolithin compounds, since they are bioavailable. Particularly, there are studies indicating the importance of ellagitannin-rich food for protective and alternative treatment of Alzheimer's Disease (AD). From this perspective, within this study, the major urolithins (that is, urolithins A and B), their methyl ether metabolites, as well as some synthetic urolithin analogs have been synthesized and screened for their biological activities in various enzyme inhibition (acetylcholinesterase, butyrylcholinesterase, monoamine oxidase B, cyclooxygenase 1, and cyclooxygenase 2) and antioxidant (DPPH radical scavenging) assay systems. The results pointed out the potential of urolithins to act as inhibitors on these receptors. Docking studies were also performed to investigate the possible interactions.

Urolithin B as a Simple, Selective, Fluorescent Probe for Sensing Iron(III) in Semi-Aqueous Solution.

The development of simple, environmental friendly, and cheap reagents with metal binding properties are quite important not only for the treatment of environmental pollution but also for their application in medicine. Within this study, for the first time, we displayed a natural chromen analogue, Urolithin B, as a simple, selective, fluorescent iron (III) sensing probe. Following the synthesis and structure identification studies, the selective metal binding property of the compound was displayed employing fluorescence techniques. Accordingly, urolithin B has the capacity to coordinate selectively to iron (III) with a 3:2 stoichiometry.

Design, synthesis and biological evaluation of novel 6H-benzo[c]chromen-6-one, and 7,8,9,10-tetrahydro-benzo[c]chromen-6-one derivatives as potential cholinesterase inhibitors.

Hydroxylated 6H-benzo[c]chromen-6-one derivatives (i.e., urolithins) are the main bioavailable metabolites, and biomarkers of ellagitannins present in various nutrition. Although these dietaries, the sources of urolithins, are employed in folk medicine as cognitive enhancer in the treatment of Alzheimer's Disease, urolithins have negligible potential to inhibit acetylcholinesterase and butyrylcholinesterase enzymes, the validated targets of Alzheimer's Disease. Therefore, within this research, a series of 6H-benzo[c]chromen-6-one, and 7,8,9,10-tetrahydro-benzo[c]chromen-6-one derivatives has been designed, synthesized, and their biological activities were evaluated as potential acetylcholinesterase and butyrylcholinesterase inhibitors. The compounds synthesized exerted comparable activity in comparison to rivastigmine, galantamine, and donepezil both in in vitro and in vivo studies.

Synthesis of benzylidene-benzofuranone derivatives as probes for detection of amyloid fibrils in cells.

Aggregated protein is the common cause of a wide variety of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease, etc. It is proven that protein aggregation like amyloid ß (Aß) is one of the critical factors causing AD and, its diagnosis in the early stages of the disease is important for the treatment or prevention of AD. To have a better understanding of protein aggregation and its pathologies, there is a huge need to design and develop new and more trustworthy probe molecules for in vitro amyloid quantification and in vivo amyloid imaging. In this study, 17 new biomarker compounds, have been synthesized from benzofuranone derivatives, to detect and identify amyloid in vitro (dye-binding assay) as well as in the cell by staining method. According to the results, some of these synthetic derivatives can be considered suitable identifiers and quantifiers to detect amyloid fibrils in vitro. Compared to thioflavin T, 4 probes out of 17 probes have shown good results in selectivity and detectability of Aß depositions, and their binding properties were also confirmed with in silico analysis. The drug-likeness prediction results for selected compounds by the Swiss ADME server show a satisfactory percentage of blood-brain barrier (BBB) permeability and gastrointestinal (GI) absorption. Among all of them, compound 10 was able to show better binding properties than others, and in vivo study showed that this compound was capable of detecting intracellular amyloid.Communicated by Ramaswamy H. Sarma.

Selected Natural and Synthetic Agents Effective against Parkinson's Disease with Diverse Mechanisms.

Similar to other neurodegenerative diseases, Parkinson's disease (PD) has been extensively investigated with respect to its neuropathological background and possible treatment options. Since the symptomatic outcomes are generally related to dopamine deficiency, the current treatment strate-gies towards PD mainly employ dopaminergic agonists as well as the compounds acting on dopamine metabolism. These drugs do not provide disease modifying properties; therefore alternative drug dis-covery studies focus on targets involved in the progressive neurodegenerative character of PD. This study has aimed to present the pathophysiology of PD concomitant to the representation of drugs and promising molecules displaying activity against the validated and non-validated targets of PD.

The Hybrid Compounds as Multi-target Ligands for the Treatment of Alzheimer's Disease: Considerations on Donepezil.

The strategies to combat Alzheimer's Disease (AD) have been changing with respect to the failures of many drug candidates assessed in clinical studies, the complex pathophysiology of AD, and the limitations of the current drugs employed. So far, none of the targets, either validated or nonvalidated, have been shown to be purely causative in the generation and development of AD. Considering the progressive and the neurodegenerative characteristics of the disease, the main strategy has been based on the design of molecules capable of showing activity on more than one receptor, and it is defined as multi-target ligand design strategy. The hybrid molecule concept is an outcome of this approach. Donepezil, as one of the currently employed drugs for AD therapy, has also been utilized in hybrid drug design studies. This review has aimed to present the promising donepezil-like hybrid molecules introduced in the recent period. Particularly, multi-target ligands with additional activities concomitant to cholinesterase inhibition are preferred.

The investigation of fluorescence and metal interaction properties of racemic 7,8,9,10-tetrahydro-3-hydroxy-4-(1-hydroxyethyl)benzo[c]chromen-6-one.

The design or investigation of fluorescence probes continues to receive attention with respect to the diverse applications of spectrofluorometry. Depending on the highly sensitive character, fluorescence spectroscopy-based methodologies have been widely used in recent years in different sciences, including analytical, environmental, and medicinal chemistry areas. In our previous works, we have shown the iron (III) selective on-off sensor properties of benzo[c]chromen-6-one derivatives. In this study, we have extrapolated this research to 4-substituted analogues and investigated both fluorescent and metal interaction properties. Following the synthesis and structure identification studies, (±)-7,8,9,10-tetrahydro-3-hydroxy-4-(1-hydroxyethyl)benzo[c]chromen-6-one was found as a fluorescent molecule displaying fluorescence enhancement in the presence of metals. This feature has been found quite different in comparison to the previous urolithins investigated. This finding suggested the substituent dependent effects and variations on the fluorescent properties of benzo[c]chromen-6-one system.

Discovery of Potent Cholinesterase Inhibition-Based Multi-Target-Directed Lead Compounds for Synaptoprotection in Alzheimer's Disease.

Drug development efforts that focused on single targets failed to provide effective treatment for Alzheimer's disease (AD). Therefore, we designed cholinesterase inhibition (ChEI)-based multi-target-directed ligands (MTDLs) to simultaneously target AD-related receptors. We built a library of 70 compounds, sequentially screened for ChEI, and determined σ1R, σ2R, NMDAR-GluN2B binding affinities, and P2X7R antagonistic activities. Nine fulfilled in silico drug-likeness criteria and did not display toxicity in three cell lines. Seven displayed cytoprotective activity in two stress-induced cellular models. Compared to donepezil, six showed equal/better synaptic protection in a zebrafish model of acute amyloidosis-induced synaptic degeneration. Two P2X7R antagonists alleviated the activation state of microglia in vivo. Permeability studies were performed, and four did not inhibit CYP450 3A4, 2D6, and 2C9. Therefore, four ChEI-based lead MTDLs are promising drug candidates for synaptic integrity protection and could serve as disease-modifying AD treatment. Our study also proposes zebrafish as a useful preclinical tool for drug discovery and development.

Substrate inhibition in human hydroxysteroid sulfotransferase SULT2A1: studies on the formation of catalytically non-productive enzyme complexes.

The cytosolic sulfotransferase hSULT2A1 is the major hydroxysteroid (alcohol) sulfotransferase in human liver, and it catalyzes the 3'-phosphoadenosine-5'-phosphosulfate (PAPS)-dependent sulfation of various endogenous hydroxysteroids as well as many xenobiotics that contain alcohol and phenol functional groups. The hSULT2A1 often displays substrate inhibition, and we have hypothesized that a key element in this response to increasing substrate concentration is the formation of non-productive ternary dead-end enzyme complexes involving the nucleotide product, adenosine 3',5'-diphosphate (PAP). One of these substrates for hSULT2A1 is dehydroepiandrosterone (DHEA), a major circulating steroid hormone in humans that serves as precursor to both androgens and estrogens. We have utilized DHEA in both initial velocity studies and equilibrium binding experiments in order to evaluate the potential role of ternary complexes in substrate inhibition of the enzyme. Our results indicate that hSULT2A1 forms non-productive ternary complexes that involve either DHEA or dehydroepiandrosterone sulfate, and the formation of these ternary complexes displays negative cooperativity in the binding of DHEA.

3-Hydroxy-7,8,9,10-tetrahydro-6H-benzo[c]chromen-6-one and 3-hydroxy-6H-benzo[c]chromen-6-one act as on-off selective fluorescent sensors for Iron (III) under in vitro and ex vivo conditions.

Regarding the abundant use of metals for different purposes, it becomes more critical from various scientific and technological perspectives to discover novel agents as selective probes for the detection of specific metals. In our previous studies, we have shown that aqueous solutions of natural urolithins (i.e., hydroxyl-substituted benzo[c]chromen-6-one derivatives) are selective Iron (III) sensors in fluorescence assays. In this study, we have extrapolated these findings to another coumarine compound (i.e., 3-Hydroxy-7,8,9,10-tetrahydro-6H-benzo[c]chromen-6-one) and compared the selective metal binding properties with Urolithin B (i.e., 3-Hydroxy-6H-benzo[c]chromen-6-one). Following the synthesis and structure identification studies, the fluorometric studies pointed out that the lactam group in the structure still persists to be the important scaffold for maintaining selective on-off sensor capacity that renders the compound a selective Iron (III) binding probe. Moreover, for the first time, fluorescence cellular imaging studies concomitant to cytotoxicity assays with the title compounds were also performed and the results displayed the cell-penetrative, safe, and fluorescent detectable characteristics of the compounds in neuroblastoma and glioblastoma cells through servings as intracellular Iron (III) on-off sensors.

Prioritizing potential ACE2 inhibitors in the COVID-19 pandemic: Insights from a molecular mechanics-assisted structure-based virtual screening experiment.

Angiotensin-converting enzyme 2 (ACE2) is a membrane-bound zinc metallopeptidase that generates the vasodilatory peptide angiotensin 1-7 and thus performs a protective role in heart disease. It is considered an important therapeutic target in controlling the COVID-19 outbreak, since SARS-CoV-2 enters permissive cells via an ACE2-mediated mechanism. The present in silico study attempted to repurpose existing drugs for use as prospective viral-entry inhibitors targeting human ACE2. Initially, a clinically approved drug library of 7,173 ligands was screened against the receptor using molecular docking, followed by energy minimization and rescoring of docked ligands. Finally, potential binders were inspected to ensure molecules with different scaffolds were engaged in favorable contacts with both the metal cofactor and the critical residues lining the receptor's active site. The results of the calculations suggest that lividomycin, burixafor, quisinostat, fluprofylline, pemetrexed, spirofylline, edotecarin, and diniprofylline emerge as promising repositionable drug candidates for stabilizing the closed (substrate/inhibitor-bound) conformation of ACE2, thereby shifting the relative positions of the receptor's critical exterior residues recognized by SARS-CoV-2. This study is among the rare ones in the relevant scientific literature to search for potential ACE2 inhibitors. In practical terms, the drugs, unmodified as they are, may be introduced into the therapeutic armamentarium of the ongoing fight against COVID-19 now, or their scaffolds may serve as rich skeletons for designing novel ACE2 inhibitors in the near future.

Porous magnetic resin-g-chitosan beads for adsorptive removal of phenolic compounds.

In this study, porous magnetic resin grafted chitosan (R-g-Ch) beads were prepared for removal of 4-chlorophenol and phenol from aqueous solutions. The R-g-Ch beads were characterized by vibrating sample magnetometer, Fourier-transform infrared spectroscopy, scanning electron microscopy and thermogravimetry methods. The removal of the phenolic compounds was optimized by varying the experimental conditions. Results herein are well fitted to the pseudo-second order kinetic and Langmuir isotherm. The maximum adsorption capacity of phenol and 4-chlorophenol were found to be 188.6 and 99 mg/g, respectively. The thermodynamic studies suggested that the adsorption process was exothermic, irreversible and feasible within the range of 298-318 K.

Benzimidazole-derived Compounds Designed for Different Targets of Alzheimer's Disease.

Benzimidazole scaffold has been efficiently used for the design of various pharmacologically active molecules. Indeed, there are various benzimidazole drugs, available today, employed for the treatment of different diseases. Although there is no benzimidazole moiety containing a drug used in clinic today for the treatment of Alzheimer's Disease (AD), there have been many benzimidazole derivative compounds designed and synthesized to act on some of the validated and non-validated targets of AD. This paper aims to review the literature to describe these benzimidazole containing molecules designed to target some of the biochemical cascades shown to be involved in the development of AD.

Pentachlorophenol and other chlorinated phenols are substrates for human hydroxysteroid sulfotransferase hSULT2A1.

Pentachlorophenol (PCP) is a persistent chemical contaminant that has been extensively investigated in terms of its toxicology and metabolism. Similar to PCP, other chlorinated phenol derivatives are also widely present in the environment from various sources. Even though some of the chlorine-substituted phenols, and particularly PCP, are well-known inhibitors of phenol sulfotransferases (SULTs), these compounds have been shown to undergo sulfation in humans. To investigate the enzymatic basis for sulfation of PCP in humans, we have studied the potential for PCP as well as the mono-, di-, tri-, and tetra-chlorinated phenols to serve as substrates for human hydroxysteroid sulfotransferase, hSULT2A1. Our results show that all of these compounds are substrates for this isoform of sulfotransferase, and the highest rates of sulfation are obtained with PCP, trichlorophenols, and tetrachlorophenols. Much lower rates of sulfation were obtained with isomers of monochlorophenol and dichlorophenol as substrates for hSULT2A1. Thus, the sulfation of polychlorinated phenols catalyzed by hSULT2A1 may be a significant component of their metabolism in humans.

Traditional Techniques Applied in Olive Oil Production Results in Lower Quality Products in Northern Cyprus.

OBJECTIVES: Olive oil production and its consumption is one of the traditional characteristics of Northern Cyprus. To date, no research has been conducted to analyze the quality of traditionally produced olive oil. Therefore, within this study, we aimed to analyze the olive oil produced within the island concomitant to the determination and comparison of its quality indices. MATERIALS AND METHODS: The standard olive oil analysis techniques acknowledged by the IOOC and ISO were employed. Accordingly, the fatty acid content, peroxide level, total phenol content, the levels of carotenoids and chlorophyll, as well as status of oxidation were all tested concomitant to statistical analysis. RESULTS: In contrast to the regional belief and consideration, the results indicated that the olive oil produced locally is highly exposed to oxidation and therefore, it is of lower quality according to the ISO guidelines. CONCLUSION: The traditional techniques employed for the production, distribution, and storage of olive oil within Northern Cyprus must be re-evaluated and controlled to satisfy the current standards required and employed globally.

Assessment of Aflatoxin M1 and Heavy Metal Levels in Mothers Breast Milk in Famagusta, Cyprus.

Breast milk contributes towards optimal nutrition for infants. However, studies showed that it can also contain different toxins and heavy metals, which reduce its health benefits. The aim of this study is to determine the level of contaminants such as aflatoxin M1 (AFM1), Pb, Cd, As, and Hg in breast milk samples from Famagusta, Cyprus. Correlations between moldy food consumption, smoking habits of the mothers, and contaminant levels in breast milk were also investigated. Breast milk samples from 50 lactating mothers in rural and urban areas of Famagusta District were analyzed for AFM1 by ELISA. Eighty percent of them were found to be contaminated with AFM1 with the mean measurement of 7.84 ± 1.72 ng/l. Socio-demographic status, moldy food consumption habits, and smoking status do not have any effect on the AFM1 levels observed in breast milk. Heavy metal levels in breast milk were examined by inductively coupled plasma mass spectrometry, and the mean measurements were1.19 ± 1.53 ppm for Pb, 0.73 ± 0.58 ppm for As, 0 ± 0.20 ppm for Hg, and 0.45 ± 0.23 ppm for Cd. This study indicates that the levels of these contaminants in breast milk samples obtained in Famagusta District are well within the acceptable levels. However, the presence of AFM1 and heavy metals still may pose risks for infant health.

Synthesis of Novel Benzothiazole-Piperazine Derivatives and Their Biological Evaluation as Acetylcholinesterase Inhibitors and Cytotoxic Agents.

OBJECTIVE AND METHOD: A new series of benzothiazole-piperazine derivatives was synthesized and a complete chemical characterization of the novel compounds was provided. In vitro cytotoxic activities were screened against colorectal (HCT-116), breast (MCF-7) and hepatocellular (Huh7) cancer cell lines by Sulforhodamine B assay. RESULT AND DISCUSSION: All compounds showed cytotoxic activity against hepatocellular (Huh7) and breast (MCF-7) cancer cell lines. Dihalo substituted benzylpiperazine derivatives (2a, 2e) had the highest cytotoxic activities in all the tested cell lines. In addition, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities of synthesized compounds were investigated by in vitro Ellman's method. Compound 2j led to moderate and selective inhibition against AChE. Docking study was utilized to understand the binding mode of compound 2j in comparision with donepezil on AChE. The other tested compounds showed weak or no inhibition against AChE as promising anticancer agents.

4-(5-chloro-2(3H)-benzoxazolon-3-yl) butanoic acid derivatives: synthesis, antinociceptive and anti-inflammatory properties.

In this study, 4-(5-chloro-2(3H)-benzoxazolone-3-yl)butanoic acid and its ethyl ester as well as its ten new amide derivatives have been synthesized. Their structures have been elucidated by IR, (1)H-NMR spectra and elemental analysis. The compounds were screened for antinociceptive and anti-inflammatory activities. The highest antinociceptive and anti-inflammatory activities were exhibited by Compound 11 which has carboxylic acid structure. A various decrease in antinociceptive and anti-inflammatory activity was observed by amidation of the carboxylic acid moiety of this compound.