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Coreopsis tinctoria Nutt. is an important medicinal plant in traditional Uyghur medicine. The skin-lightening potential of the flower has been recognized recently; however, the active compounds responsible for that are not clear. In this work, tyrosinase, a target protein for regulating melanin synthesis, was immobilized on the Whatman paper for the first time to screen skin-lightening compounds present in the flower. Quercetagetin-7- O -glucoside ( 1 ), marein ( 2 ), and okanin ( 3 ) were found to be the enzyme inhibitors. The IC 50 values of quercetagetin-7- O -glucoside ( 1 ) and okanin ( 3 ) were 79.06 ± 1.08 μM and 30.25 ± 1.11 μM, respectively, which is smaller than 100.21 ± 0.11 μM of the positive control kojic acid. Enzyme kinetic analysis and molecular docking were carried out to investigate their inhibition mechanism. Although marein ( 2 ) showed a weak inhibition effect in vitro, it inhibited the intracellular tyrosinase activity and diminished melanin production in melanoma B16 cells as did the other two inhibitors. The paper-based ligand fishing method developed in this work makes it effective to quickly screen tyrosinase inhibitors from natural products. This is the first report on the tyrosinase inhibitory effect of those three compounds, showing the promising potential of Coreopsis tinctoria for the development of herbal skin-lightening products.

Paper sludge (PS) from paper mills has a significant potential for bioethanol production. In this study, waste-paper-containing PS is used as the raw material for bioethanol production because the annual waste paper utilization rate has increased globally. Although PS does not require delignification, the antiseptics and deinking agents in waste paper-containing PS inhibit enzymatic reactions such as saccharification and fermentation. Their removal is important, but it has not yet been reported. Using subcritical water pretreatment, the selective decomposition of enzyme inhibitors in PS is examined without the generation of other enzyme inhibitors. The optimum pretreatment conditions are identified as 240 °C, 3.3 MPa, 3 min, and pH 4.5. Glucose was obtained in 71% yield from pretreated 5 wt% PS using cellulase, which is 5.5 times higher than that from unpretreated PS. This is because the reactivity of the pretreated PS increases with increasing surface area of the cellulose fibers, and the cellulase inhibitors are decomposed by subcritical water. Next, semi-simultaneous saccharification and fermentation treatments are performed to produce bioethanol from waste-paper-containing PS. The bioethanol yield based on cellulose after 96 h is 68% for PS pretreated with subcritical water, whereas the bioethanol yield is 6% for unpretreated PS. Therefore, subcritical water pretreatment increases the bioethanol yield by 11 times. The proposed method may enable the use of large amounts of PS as ethanol feedstock in future. [ABSTRACT FROM AUTHOR]

In this study, xanthine oxidase was immobilized for the first time using a novel magnetic metal-organic framework material (Fe 3 O 4 -SiO 2 -NH 2 @MnO 2 @ZIF-8-NH 2 ). A ligand fishing method was established to rapidly screen XOD inhibitors from Ligusticum wallichii based on the immobilized XOD. Characterization and properties of the immobilized enzyme revealed its excellent stability and reusability. A ligand was screened from Ligusticum wallichii and identified as ligustilide by ultra-high performance liquid chromatography tandem mass spectrometry. The IC 50 value of ligustilide was determined to be 27.70 ± 0.13 μM through in vitro inhibition testing. Furthermore, molecular docking verified that ligustilide could bind to amino acid residues at the active site of XOD. This study provides a rapid and effective method for the preliminary screening of XOD inhibitors from complex natural products and has great potential for further discovery of anti-hyperuricemic compounds., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Microbial metabolites are an important source of tyrosinase (TYR) inhibitors because of their rich chemical diversity. However, because of the complex metabolic environment of microbial products, it is difficult to rapidly locate and identify natural TYR inhibitors. Affinity-based ligand screening is an important method for capturing active ingredients in complex samples, but ligand immobilization is an important factor affecting the screening process. In this paper, TYR was used as ligand, and the SpyTag/SpyCatcher coupling system was used to rapidly construct affinity chromatography vectors for screening TYR inhibitors and separating active components from complex samples. We successfully expressed SpyTag-TYR fusion protein and SpyCatcher protein, and incubated SpyCatcher protein with epoxy-activated agarose. The SpyTag-TYR protein was spontaneously coupled with SpyCatcher to obtain an affinity chromatography filler for immobilization of TYR, and the performance of the packaging material was characterized. Finally, compound 1 with enzyme inhibitory activity was successfully obtained from the fermentation product of marine microorganism C. Through HPLC, MS, 1 H NMR and 13 C NMR analyses, its structure was deduced as azelaic acid, and its activity was analyzed. The results showed that this is a feasible method for screening TYR inhibitors in complex systems., (© 2024 John Wiley & Sons Ltd.)

Covalent organic frameworks (COFs) with large specific surface areas, high porosity, good stability, and designable structure are promising carriers for immobilized enzymes. It is important to explore lipase inhibitors from natural foods as lipase inhibitors are closely related to the treatment of obesity. In this work, a carboxyl functionalized covalent organic framework (TpBD-3COOH) was prepared by solvothermal method for covalent immobilization of porcine pancreatic lipase (PPL) and obtained the enzyme-decorated COF (PPL@COF). The immobilized lipase showed wider pH and temperature tolerance with the same optimal pH and temperature of 7.5 and 50 ℃ compared to free lipase. After 6 successive reuses, the PPL@COF maintained 53.0% of its original activity. Immobilized lipase also displayed enhanced storage stability (55.4% after 14 days at 4 ℃). When p-nitrophenyl acetate was applied as the substrate, the calculated Michaelis constant was 3.57 mM and the half maximal inhibitory concentration of orlistat was 3.20 μM. Finally, the PPL@COF was used for enzyme inhibitors screening from natural foods combined with UV spectrophotometry, and Hawthorn was screened for excellent lipase inhibitory activity., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

On-site multi-enzymes detection and inhibitors screening are still challenging and particularly urgent. Here, dual-channel foldable microfluidic paper (μPAD)-based parallel enzymatic reaction systems were fabricated for simultaneous visual colorimetric detecting acetylcholinesterase (AChE) and α-glucosidase (α-Glu) together with screening inhibitors. μPAD composing of two layers with dual channels was designed and prepared facilely by a permanent marker. AChE and α-Glu catalyze pre-loaded substrates into products (thiocholine (TCh), ascorbic acid (AA)) on the 1st layer. Parallelly, oxidase-like MnO 2 nanosheets oxidize pre-dropped colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB) on the 2nd layer. After simple folding μPAD, TCh and AA can reduce oxTMB to TMB, resulting in color fading. Obviously, bioenzyme and nanozyme reactions under different pH can simultaneously occur on the μPAD. Furthermore, colorimetric results can be easily captured and on-site quantitatively analyzed by smartphone. As a result, a convenient, efficient, sensitive, and specific platform has been constructed for simultaneous detecting AChE and α-Glu in human serum samples (recoveries, 92.1–105.0%; relative standard deviations, < 3.6%), and screening inhibitors from synthesized compounds and natural products. The developed platform provides constructive insights for exploitation of visual detecting strategies for simultaneous sensing muti-targets for point-of-care testing of disease and development of drugs. [Display omitted] • Visual colorimetric detection of AChE and α-Glu and screening of inhibitors. • Dual-channel foldable μ PAD for on-site simultaneous visual detection. • Parallel enzymatic reaction strategy matches different working pH. • The proposed platform had facile, portable, and visual advantages in POCT. [ABSTRACT FROM AUTHOR]

We report the screening of angiotensin converting enzyme (ACE) inhibitors on an origami microfluidic paper-based analytical device (μPAD) using colorimetric detection. The hydrolysis product reacts with ninhydrin, resulting in a purple color at the detection zones. Images of the μPADs are captured using a common cell phone and analyzed with Photoshop software. This platform allows six independent colorimetric reactions to take place simultaneously, and the IC 50 values can be obtained in a single run within 22 min. The relative standard deviations of inhibition efficiencies are generally lower than 4.0 % (n = 5). The IC 50 values of captopril and five products from natural plants were obtained and corresponded well with UV methods. The relative deviations between the two methods are within the range of −5 % to +5 %. This work is a proof-of-concept successfully demonstrating the use of μPADs technology to screen enzyme inhibitors from natural products. • An enzyme-based drug screening method based on origami microfluidic paper-based analytical devices (μPADs) was developed. • The system allows for simultaneous performance of six independent reactions. IC 50 of an inhibitor can be rapidly obtained. • It allows a rapid confirmation of the presence of potential ACEIs in the sample simply by judgment with naked eye. • The μPAD requires minimal use of reagents and supporting equipment. The IC 50 values corresponded well with UV methods. [ABSTRACT FROM AUTHOR]

Simple Summary: This review discusses the enzymatic processes governing the initial stages of the synthesis of glycerophospholipids (phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine) and triacylglycerol. The key enzymes analyzed include glycerol-3-phosphate acyltransferases (GPAT) and 1-acylglycerol-3-phosphate acyltransferases (AGPAT). Additionally, because most AGPATs have lysophospholipid acyltransferase (LPLAT) activity, enzymes involved in the Lands cycle with similar functions were also included. The review further explores the potential therapeutic implications of inhibiting these enzymes in the treatment of metabolic diseases and cancer. By elucidating the enzymatic pathways involved in lipid synthesis and their impact on various pathological conditions, the article contributes to the understanding of these processes and their potential as therapeutic targets. This review delves into the enzymatic processes governing the initial stages of glycerophospholipid (phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine) and triacylglycerol synthesis. The key enzymes under scrutiny include GPAT and AGPAT. Additionally, as most AGPATs exhibit LPLAT activity, enzymes participating in the Lands cycle with similar functions are also covered. The review begins by discussing the properties of these enzymes, emphasizing their specificity in enzymatic reactions, notably the incorporation of polyunsaturated fatty acids (PUFAs) such as arachidonic acid and docosahexaenoic acid (DHA) into phospholipids. The paper sheds light on the intricate involvement of these enzymes in various diseases, including obesity, insulin resistance, and cancer. To underscore the relevance of these enzymes in cancer processes, a bioinformatics analysis was conducted. The expression levels of the described enzymes were correlated with the overall survival of patients across 33 different types of cancer using the GEPIA portal. This review further explores the potential therapeutic implications of inhibiting these enzymes in the treatment of metabolic diseases and cancer. By elucidating the intricate enzymatic pathways involved in lipid synthesis and their impact on various pathological conditions, this paper contributes to a comprehensive understanding of these processes and their potential as therapeutic targets. [ABSTRACT FROM AUTHOR]

Src Homology 2-containing Inositol 5'-Phosphatase-1 (SHIP-1), encoded by INPP5D, has been identified as an Alzheimer's disease (AD) risk-associated gene through recent genetic and epigenetic studies. SHIP-1 confers AD risk by inhibiting the TREM2 cascade and reducing beneficial microglial cellular processes, including phagocytosis. While several small molecules have been reported to modulate SHIP-1 activity, their limited selectivity and efficacy in advanced models restricted their potential as therapeutic agents or probes for biological studies. Herein, we validated and implemented a high-throughput screening platform to explore new chemotypes that can modulate the phosphatase activity of SHIP-1. We screened 49,260 central nervous system (CNS)-penetrate compounds sourced from commercial vendors using the malachite green-based assay for anti-SHIP-1 activity. Through analysis, prioritization, and validation of the screening hits, we identified three novel types of scaffolds that inhibit the SHIP-1 phosphatase activity with IC 50 s as low as 46.6 µM. To improve the inhibitory activity of these promising hits, we carried out structure-activity relationship (SAR) studies, resulting in a lead molecule SP3-12 that inhibits SHIP-1 with an IC 50 value of 6.1 μM. Kinetic analyses of SP3-12 revealed that its inhibition mechanism is competitive, with a K i value of 3.2 µM for SHIP-1 and a 7-fold selectivity over SHIP-2. Furthermore, results from testing in a microglial phagocytosis/cell health high content assay indicated that SP3-12 could effectively activate phagocytosis in human microglial clone 3 (HMC3) cells, with an EC 50 of 2.0 µM, without cytotoxicity in the dose range. Given its potency, selectivity, and cellular activity, SP3-12 emerges as a promising small molecule inhibitor with potential for investigating the biological functions of SHIP-1., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Inhibition of tyrosinase by gallic acid, epigallocatechin, and epigallocatechin-3-gallate has been recently described in several publications. However, oxidation of these compounds by this enzyme was demonstrated long time ago. Gallic acid also reduced tyrosinase-generated o-quinones. We have shown that epigallocatechin and epigallocatechin-3-gallate are also rapidly oxidized by o-quinones generated from catechols by tyrosinase or by treatment with sodium periodate. Smaller changes of absorbance at 475 nm during oxidation of l-dopa in the presence of gallic acid, epigallocatechin, and epigallocatechin-3-gallate result from reduction of dopaquinone by these compounds. This reaction prevents formation of dopachrome giving an effect of inhibition, which is only apparent. The actual reaction rates measured by oxygen consumption did not decrease in the presence of these compounds. The standard spectrophotometric assay cannot therefore be used to monitor tyrosinase activity with compounds possessing strong reducing properties, particularly flavonoids, because their influence on dopachrome formation does not result from inhibition of this enzyme. Such compounds should be considered antimelanogenic or antibrowning agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is a key enzyme in the folate biosynthesis pathway. It catalyzes the pyrophosphoryl transfer from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP). HPPK is essential for microorganisms but is absent in mammals. Yet, it is not the target of any existing antibiotics. Hence, this enzyme is an attractive target for developing novel antimicrobial agents. A wealth of structural and mechanistic information has provided solid basis for structure-based design of HPPK inhibitors. Our bisubstrate inhibitors were initially created by linking 6-hydroxymethylpterin to adenosine through 2, 3, or 4 phosphate groups (HP n A, n = 2, 3, or 4), among which HP 4 A exhibited the highest binding affinity (K d  = 0.47 ± 0.04 μM). Further development was carried out based on high-resolution structures of HPPK in complex with HP 4 A. Replacing the phosphate bridge with a piperidine linked thioether eliminated multiple negative charges of the bridge. Substituting the pterin moiety with 7,7-dimethyl-7,8-dihydropterin improved the binding affinity. Arming the piperidine ring with a carboxyl group and oxidizing the thioether further enhanced the potency, resulting in a druglike inhibitor of HPPK (K d  = 0.047 ± 0.007 μM). None of these inhibitors, however, exhibits bacterial cell permeability. It is most likely due to the lack of active folate transporters in bacteria. Replacing the pterin moiety with a 7-deazagaunine moiety, we have obtained a novel bisubstrate inhibitor (HP-101) showing observable cell permeability toward a Gram-positive bacterium. Here, we report the in vitro activity of HP-101 and its structure in complex with HPPK, providing a framework for structure-based further development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

DHODH inhibition represents an attractive approach to overcome differentiation blockade for the treatment of AML. In a previous communication, we described our efforts leading to the discovery of compound 3 (JNJ-74856665), an orally bioavailable, potent, and selective DHODH inhibitor for clinical development. Guided by the co-crystal structures bound to human DHODH, other fused six-membered constructs were explored as isosteric replacements of the isoquinolinone central core. The correct positioning of the nitrogen in these core systems proved to be essential in modulating potency. Herein is described the synthesis of these complexly functionalized cores and their profiling, leading to DHODH inhibitors that possess favorable properties suitable for further development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study evaluates vacuum drying (VD), microwave drying (MD), hot air drying (HAD), and freeze drying (FD), on the color and microstructure changes of Ascophyllum nodosum (A. nodosum), which affect the extraction of polyphenols and flavonoids. During drying, VD and FD show slight color change and looser structure, aiding in active compound preservation and extraction. Polyphenols extracted from A. nodosum (PEAn) using these methods show higher anti-tyrosinase activity, with VD treatment exhibiting the strongest inhibition. Kinetic studies demonstrate competitive inhibition between PEAn and tyrosinase. The binding constant (K i ) values indicate that PEAn treated with VD exhibits the most effective inhibition on tyrosinase, and the Zeta potential suggests the formation of the most stable complex. Circular dichroism (CD) spectroscopy shows significant enzyme rearrangement with VD-treated PEAn. Molecular docking confirms strong binding affinity. This study aims to enhance the utility of A. nodosum and develop novel uses for tyrosinase inhibitors in food., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The present study found for the first time that phenolic glycosides were an important material basis for mulberry leaves to inhibit lipase. The corresponding IC 50 for hyperoside, rutin, astragalin and quercetin were 68, 252, 385 and 815 μg/mL respectively. The inhibitory effect was ranked as monoglycosides > phenolic hydroxyl groups > disaccharides on the benzone ring. Hyperoside bound to lipase in competitive inhibition type with one binding site, while the others bound to lipase in a mixed inhibition type by two similar sites. All four compounds altered the microenvironment and secondary conformation of lipase through static quenching. The docking score, stability, and binding energy were consistent with the compound inhibitory activity. The main binding between compounds and lipase amino acid residues were spontaneously though hydrophobic interactions and hydrogen bonding. The strong hydrogen bonds formed with SER-152 inside the lipase pocket, might be important for the strong inhibitory activity of hyperoside., Competing Interests: Declaration of competing interest The authors declare that they have no financial interest or personal relationships which influenced the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Neuraminidase (NA) has been well-studied as a therapeutic target for Influenza. However, resistance to the influenza virus has been observed recently. Out of special interest in the utilization of dietary antivirals from citrus, in vitro inhibition activity against NA and in silico studies including molecular docking, molecular dynamic simulation, and a predictive ADMET study, were performed on five citrus-derived flavanones. Encouragingly, citrus-derived flavanones displayed comparable or even more potent in vitro inhibitory activity than oseltamivir carboxylate against NA. Orange peel extract exhibited higher activity than hesperidin. Among the tested compounds, neohesperidin, forming strong hydrogen-bonding interactions with key arginine residues, exhibited the most effective inhibitory activity against NAs from C. perfringens, consistent with the results of molecular dynamics simulations. Although the molecular docking results were inconsistent with the in vitro activity, the binding energy was identical against the wild-type and mutant, suggesting a lower likelihood of developing drug resistance. Moreover, predictive ADMET studies showed favorable pharmacokinetic properties for the tested compounds. Overall, citrus fruit peel emerges as a promising dietary supplement for prevention and treatment of influenza. These findings elucidate the impact of flavanones on NA activity, and the analysis of their binding modes provides valuable insights into the mechanism of NA inhibition., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Siming Zhu reports financial support was provided by the Science and Technology Innovation Strategy Special Project in Guangdong Province, P.R. China. Siming Zhu reports financial support was provided by the Science and Technology Planning Project of Agricultural Division 9 in Xinjiang Production and Construction Corps., P.R. China. Siming Zhu reports financial support was provided by the Science and Technology Planning Project in Guangdong, P.R. China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Masson SAS.)

Influenza viruses that cause seasonal and pandemic flu are a permanent health threat. The surface glycoprotein, neuraminidase, is crucial for the infectivity of the virus and therefore an attractive target for flu drug discovery campaigns. We have designed and synthesized more than 40 3-indolinone derivatives. We mainly investigated the role of substituents at the 2 position of the core as well as the introduction of substituents or a nitrogen atom in the fused phenyl ring of the core for inhibition of influenza virus neuraminidase activity and replication in vitro and in vivo. After evaluating the compounds for their ability to inhibit the viral neuraminidase, six potent inhibitors 3c, 3e, 7c, 12o, 12v, 18d were progressed to evaluate for cytotoxicity and inhibition of influenza virus A/PR/8/34 replication in in MDCK cells. Two hit compounds 3e and 12o were tested in an animal model of influenza virus infection. Molecular mechanism of the 3-indolinone derivatives interactions with the neuraminidase was revealed in molecular dynamic simulations. Proposed inhibitors bind to the 430-cavity that is different from the conventional binding site of commercial compounds. The most promising 3-indolinone inhibitors demonstrate stronger interactions with the neuraminidase in molecular models that supports proposed binding site., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Excessive tyrosinase expression leads to pigmented diseases in humans and browning in plants, necessitating effective tyrosinase inhibitors. This study investigated the inhibitory effect and mechanism of 7-hydroxycoumarin-3-carboxylic acid (7-HC-3-CA) on tyrosinase. Using UV-visible absorption spectroscopy, we found that 7-HC-3-CA effectively inhibited tyrosinase activity, with an IC 50 value of 364 ± 1.3 μM. Enzyme kinetics, fluorescence methods and molecular simulation techniques revealed that 7-HC-3-CA acted as a reversible and competitive inhibitor, forming a stable complex with tyrosinase through hydrophobic interactions and hydrogen bonding. This altered the microenvironment of Tyr and Trp residues, causing the structural stretching and conformational changes that diminish catalytic activity. Preservation experiments demonstrated that 0.5 mM 7-HC-3-CA significantly reduced mass loss and decreased browning of fresh-sliced apples. It also lowered polyphenol oxidase activity from 0.22 to 0.18 and delayed phenolic oxidation, enhancing total phenolic content from 0.34 to 0.54, thereby controlling browning and extending storage life. Cell assays indicated that 0.5 mM 7-HC-3-CA had no significant impact on cell proliferation, with viability over 80 %. Acute toxicity tests proved that 0.5 mM of 7-HC-3-CA is completely non-lethal to KM mice. In conclusion, this study confirmed 7-HC-3-CA was a viable and safe antibrowning agent and revealed its potential application in the field of food preservation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Bisdemethoxycurcumin (BDMC), a demethoxy derivative of curcumin, has garnered interest for its potential anti-tyrosinase properties, which are crucial for applications in food preservation and cosmetic industries. Despite its recognized bioactive effects, the detailed inhibitory action and interaction of BDMC on tyrosinase and its application in anti-browning processes remain unclear. This study aims to dissect the molecular interactions of BDMC with tyrosinase, elucidate its inhibition mechanism, and assess its efficacy in preventing browning, thereby underpinning its potential as a natural anti-browning agent. Employing a battery of spectroscopic techniques, we characterized the interaction of BDMC with tyrosinase. The anti-browning properties of BDMC were evaluated on fresh-cut apples, and its effect on enzymatic activities related to browning was also investigated. The results indicate that BDMC interacts with tyrosinase in a reversible mixed-type inhibition manner with an IC 50 value of 12.5 ± 0.2 μM. Surface Plasmon Resonance (SPR) results indicated that BDMC presented good binding affinity toward tyrosinase. Fluorescence quenching results showed that BDMC could quench the fluorescence of tyrosinase in a static process. Synchronous fluorescence, circular dichroism spectra, and three-dimensional fluorescence results indicated that interaction of BDMC against tyrosinase resulted in changes of tyrosinase on microenvironment and conformation, thus causing decrease of tyrosinase activity. Copper-chelating results presented that BDMC could chelate to copper with stoichiometric ratio of 1: 2. Molecular docking provided intricate details of how BDMC interacted with tyrosinase. Moreover, BDMC exhibited anti-browning capability on fresh cut apples, and could regulate PPO, POD, and APX activities. The comprehensive analysis proposed in this study consolidated the theoretical basis of BDMC as a tyrosinase inhibitor and supported its potential anti-browning application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Catechins compounds from tea have demonstrated significant inhibitory effects on xanthine oxidase (XOD). However, the precise inhibitory mechanisms of the main catechins on XOD remain to be fully elucidated. This study explored the inhibition mechanisms and binding characteristics of five catechins (GC, EGC, EC, EGCG, and ECG) on XOD through a combination of inhibition kinetics, multi-spectroscopy analysis, molecular docking, and dynamics simulations. Among the catechins, EGCG and ECG exhibited the most potent inhibitory activities against XOD. All five catechins were found to exhibit mixed inhibition, affecting the hydrophobic groups and secondary structure of XOD predominantly through hydrophobic interactions and hydrogen bonding. Molecular dynamics simulations revealed that a 3,4,5-trihydroxybenzoic acid moiety at C 3 position significantly enhances the binding affinity of EGCG and ECG to XOD. Additionally, the decrease of β-sheet and random coil induced by EGCG and ECG was found to be crucial for enhancing inhibitory activity of XOD. In vitro cell experiments showed that EGCG and ECG significantly reduced high uric acid levels of BRL-3A cell. This study elucidates the inhibitory mechanisms of catechins on XOD, paving the way for their application as XOD inhibitors to combat hyperuricemia., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Xanthine oxidase (XO), which plays a key role in purine metabolism, is an important target enzyme for the prevention and treatment of hyperuricemia. Inhibitory activity against XO is a common criterion for the screening of compounds with potential anti-hyperuricemic activity. In this study, 22 XO inhibitors were used to construct a 3D-QSAR pharmacophore model. Subsequently, molecular docking and in vitro activity evaluations were used to identify strong XO inhibitors from a list of 2000 natural compounds. The interaction mechanisms of these compounds with XO were analyzed based on inhibition kinetics and multi-spectral analyses. The pharmacophore model was composed of three hydrogen bond receptors and a hydrophobic center. The screened compounds - Diosmetin, Fisetin, and Genistein - all showed good XO inhibitory activity, with IC 50 values of 1.86 ± 0.11 μM, 5.83 ± 0.08 μM, and 7.56 ± 0.10 μM, respectively. Kinetic analysis, fluorescence quenching assays, and molecular docking experiments showed that Diosmetin, Fisetin, and Genistein docked near the same active site of XO, mainly affecting the microenvironment of tryptophan residues. These molecules showed static binding to XO via hydrogen bonds, hydrophobic interactions, and van der Waals forces. Diosmetin and Genistein were competitive inhibitors, whereas Fisetin was a mixed inhibitor. Infrared spectroscopy showed that Diosmetin, Fisetin, and Genistein increased the α-helix content of XO from 7.4 % to 16.6 %, 21.4 %, and 11.2 %, respectively, thereby enhancing its stability. In summary, the pharmacophore model constructed in this study was accurate. The flavonoids Diosmetin, Fisetin, and Genistein effectively inhibited the activity of XO, and the amino acid residues LEU257, ILE353, and VAL259 played a key role in the interaction between the flavonoids and XO. These findings are of great significance for the screening and development of new XO inhibitors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Diabetes mellitus significantly increases mortality and morbidity rates due to complications like neuropathy and nephropathy. It also leads to retinopathy and cataract formation, which is a leading cause of vision disability. The polyol pathway emerges as a promising therapeutic target among the various pathways associated with diabetic complications. This review focuses on the development of natural and synthetic aldose reductase inhibitors (ARIs), along with recent discoveries in diabetic complication treatment. AR, pivotal in the polyol pathway converting glucose to sorbitol, plays a key role in secondary diabetes complications' pathophysiology. Understanding AR's function and structure lays the groundwork for improving ARIs to mitigate diabetic complications. New developments in ARIs open up exciting possibilities for treating diabetes-related complications. However, it is still challenging to get preclinical successes to clinical effectiveness because of things like differences in how the disease starts, drug specificity, and the complexity of the AR's structure. Addressing these challenges is crucial for developing targeted and efficient ARIs. Continued research into AR's structural features and specific ARIs is essential. Overcoming these challenges could revolutionize diabetic complication treatment, enhance patient outcomes, and reduce the global burden of diabetes-related mortality and morbidity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

High levels of extracellular adenosine in tumor microenvironment (TME) has extensive immunosuppressive effect. CD73 catalyzes the conversion of AMP into adenosine and regulates its production. Inhibiting CD73 can reduce the level of adenosine and reverse adenosine-mediated immune suppression. Therefore, CD73 has emerged as a valuable target for cancer immunotherapy. Here, a new series of malonic acid non-nucleoside derivatives were designed, synthesized and evaluated as CD73 inhibitors. Among them, compounds 18 and 19 exhibited significant inhibition activities against hCD73 with IC 50 values of 0.28 μM and 0.10 μM, respectively, suggesting the feasibility of replacing the benzotriazole moiety in the lead compound. This study explored the novelty and structural diversity of CD73 inhibitors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study reports the Design Hypothesis of a novel series of 1,3-diphenyl pyrazole-thiosemicarbazone as novel tyrosinase inhibitors (TYRI). The designed compounds were prepared and their TYRI activity and mechanisms were studied. The results showed that the selected compounds exhibited potent tyrosinase inhibitory activities greater than that of kojic acid (KA). Lead candidates, denoted as 6g and 6n, with a para-hydroxyphenyl group attached to the 3-position of the pyrazole ring demonstrated IC 50 values of 2.09 and 3.18 µM, respectively. The potency of these compounds was approximately 5-8 times higher than that of KA. The in vitro melanin content of 6g or 6n-treated melanoma cells resulted in significant efficacy in melanin reduction. The DPPH assay result revealed that the tyrosinase inhibition mechanism for these derivatives was independent of a redox effect and corresponded to the interaction with tyrosinase. According to the Lineweaver-Burk plot, the most potent compounds, 6g and 6n, exhibit a mixed type of inhibition, primarily noncompetitive inhibition. In silico molecular docking studies were employed to determine the binding mode and explore the Design Hypothesis in detail. The results suggested that these compounds could be considered promising leads for the further development of novel inhibitors to treat disorders related to tyrosinase., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Urease is a metalloenzyme that contains two Ni(II) ions in its active site and catalyzes the hydrolysis of urea into ammonia and carbon dioxide. The development of effective urease inhibitors is crucial not only for mitigating nitrogen losses in agriculture but also for offering an alternative treatment against infections caused by resistant pathogens that utilize urease as a virulence factor. This study focuses on synthesizing and investigating the urease inhibition potential of Biginelli Adducts bearing a boric acid group. An unsubstituted or hydroxy-substituted boronic group in the Biginelli adducts structure enhances the urease inhibitory activity. Biophysical and kinetics studies revealed that the best Biginelli adduct (4e; IC 50  = 132 ± 12 µmol/L) is a mixed inhibitor with higher affinity to the urease active site over an allosteric one. Docking studies confirm the interactions of 4e with residues essential for urease activity and demonstrate its potential to coordinate with the nickel atoms through the oxygen atoms of carbonyl or boronic acid groups. Overall, the Biginelli adduct 4e shows great potential as an additive for developing enhanced efficiency fertilizers and/or for medical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Mimicking the transition state of tryptophan (Trp) and O 2 in the enzymatic reaction is an effective approach to design indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors. In this study, we firstly assembled a small library of 2-substituted benzo-fused five membered heterocycles and found 2-sulfinyl-benzoxazoles with interesting IDO1 inhibitory activities. Next the inhibitory activity toward IDO1 was gradually improved. Several benzoxazoles showed potent IDO1 inhibitory activity with IC 50 of 82-91 nM, and exhibited selectivity between IDO1 and tryptophan 2,3-dioxygenase (TDO2). Enzyme binding studies showed that benzoxazoles are reversible type II IDO1 inhibitors, and modeling studies suggested that the oxygen atom of the sulfoxide in benzoxazoles interacts with the iron atom of the heme group, which mimics the transition state of Fe-O-O-Trp complex. Especially, 10b can effectively inhibit the NO production in lipopolysaccharides (LPS) stimulated RAW264.7 cells, and it also shows good anti-inflammation effect on mice acute inflammation model of croton oil induced ear edema., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Tyrosinase inhibitors are studied in the cosmetics and pharmaceutical sectors as tyrosinase enzyme is involved in the biosynthesis and regulation of melanin, hence these inhibitors are beneficial for the management of melanogenesis and hyperpigmentation-related disorders. In the current work, a novel series of diphenyl urea derivatives containing a halo-pyridine moiety (5a-t) was synthesized via a multi-step synthesis. In vitro, tyrosinase inhibitory assay results showed that, except for two compounds, the derivatives were excellent inhibitors of human tyrosinase. The average IC 50 value of the inhibitors (15.78 μM) is lower than that of kojic acid (17.3 μM) used as the reference compound, indicating that, on average, these molecules are more potent than the reference. Derivative 5a was identified as the most potent human tyrosinase inhibitor of the series, with an IC 50 value of 3.5 ± 1.2  μM, approximately 5 times more potent than kojic acid. To get further insights into the nature of binding site interactions, molecular docking and molecular dynamics simulation studies were carried out. Moreover, the evaluation of in silico ADME properties showed a highly favorable profile for the synthesized compounds. These findings suggested that the further development of this class of compounds could be useful to get potent drug-like compounds that can target hyperpigmentation-related disorders., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

The development of natural inhibitors of polyphenol oxidase (PPO) is crucial in the prevention of enzymatic browning in fresh foods. However, few studies have focused on the effect of subsequent sterilization on their inhibition efficiency. This study investigated the influence and mechanism of high hydrostatic pressure (HHP) on the inhibition of PPO by epigallocatechin gallate (EGCG), cyanidin-3-O-glucoside (C3G), and ferulic acid. Results showed that under the conditions of 550 MPa/30 min, the activity of EGCG-PPO decreased to 55.92%, C3G-PPO decreased to 81.80%, whereas the activity of FA-PPO remained stable. Spectroscopic experiments displayed that HHP intensified the secondary structure transformation and fluorescence quenching of PPO. Molecular dynamics simulations revealed that at 550 MPa, the surface interaction between PPO with EGCG or C3G increased, potentially leading to a reduction in their activity. In contrast, FA-PPO demonstrated conformational stability. This study can provide a reference for the future industrial application of natural inhibitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Despite recent advances in the treatment of cancer, the issue of therapy resistance remains one of the most significant challenges in the field. In this context, signaling molecules, such as cytokines have emerged as promising targets for drug discovery. Examples of cytokines include macrophage migration inhibitory factor (MIF) and its closely related analogue D-dopachrome tautomerase (D-DT). In this study we aim to develop a new chemical class of D-DT binders and subsequently create a dual-targeted inhibitor that can potentially trigger D-DT degradation via the Proteolysis Targeting Chimera (PROTAC) technology. Here we describe the synthesis of a novel library of 1,2,3-triazoles targeting D-DT. The most potent derivative 19c (IC 50 of 0.5 ± 0.04 μM with high selectivity toward D-DT) was attached to a cereblon (CRBN) ligand through aliphatic amides, which were synthesized by a remarkably convenient and effective solvent-free reaction. Enzyme inhibition experiments led to the discovery of the compound 10d, which exhibited moderate inhibitory potency (IC 50 of 5.9 ± 0.7 μM), but unfortunately demonstrated no activity in D-DT degradation experiments. In conclusion, this study offers valuable insight into the SAR of D-DT inhibition, paving the way for the development of novel molecules as tools to study D-DT functions in tumor proliferation and, ultimately, new therapeutics for cancer treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

DNA methyltransferases (DNMTs) play a crucial role in genomic DNA methylation. In mammals, DNMTs regulate the dynamic patterns of DNA methylation in embryonic and adult cells. Abnormal functions of DNMTs are often indicative of cancers, including overall hypomethylation and partial hypermethylation of tumor suppressor genes (TSG), which accelerate the malignancy of tumors, worsen the condition of patients, and significantly exacerbate the difficulty of cancer treatment. Currently, nucleoside DNMT inhibitors such as Azacytidine and Decitabine have been approved by the FDA and EMA for the treatment of acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), and myelodysplastic syndrome (MDS). Therefore, targeting DNMTs is a very promising anti-tumor strategy. This review mainly summarizes the therapeutic effects of DNMT inhibitors on cancers. It aims to provide more possibilities for the treatment of cancers by discovering more DNMT inhibitors with high activity, high selectivity, and good drug-like properties in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

SHP2 (Src homology-2-containing protein tyrosine phosphatase 2) plays an important role in cell proliferation, survival, migration by affecting RAS-ERK, PI3K-AKT, JAK-STAT signaling pathways and so on. Overexpression or gene mutation of SHP2 is closely linked with a variety of cancers, making it a potential therapeutic target for cancer disease. In this paper, 30 target compounds bearing pyrido[1,2-a]pyrimidin-4-one core were synthesized via two-round design strategy by means of scaffold hopping protocol. It was evaluated the in vitro enzymatic inhibition and cell antiproliferation assay of these targets. 13a, designed in the first round, presented relatively good inhibitory activity, but its molecular rigidity might limit further improvement by hindering the formation of the desired "bidentate ligand", as revealed by molecular docking studies. In our second-round design, S atom as a linker was inserted into the core and the 7-aryl group to enhance the flexibility of the structure. The screening result revealed that 14i could exhibit high enzymatic activity against full-length SHP2 (IC 50  = 0.104 μM), while showing low inhibitory effect on SHP2-PTP (IC 50  > 50 μM). 14i also demonstrated high antiproliferative activity against the Kyse-520 cells (IC 50  = 1.06 μM) with low toxicity against the human brain microvascular endothelial cells HBMEC (IC 50  = 30.75 μM). 14i also displayed stronger inhibitory activities on NCI-H358 and MIA-PaCa2 cells compared to that of SHP099. Mechanistic studies revealed that 14i could induce cell apoptosis, arrest the cell cycle at the G0/G1 phase and downregulate the phosphorylation levels of Akt and Erk1/2 in Kyse-520 cells. Molecular docking and molecular dynamics studies displayed more detailed information on the binding mode and binding mechanism of 14i and SHP2. These data suggest that 14i has the potential to be a promising lead compound for our further investigation of SHP2 inhibitors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Human glutaminyl cyclase (hQC) inhibitors have great potential to be used as anti- Alzheimer's disease (AD) agents by reducing the toxic pyroform of β-amyloid in the brains of AD patients. The four-dimensional quantitative structure activity relationship (4D-QSAR) model of N-substituted urea/thioureas was established with satisfying predictive ability and statistical reliability (Q 2 = 0.521, R 2 = 0.933, R 2 prep = 0.619). By utilizing the developed 4D-QSAR model, a set of new N-substituted urea/thioureas was designed and evaluated for their Absorption Distribution Metabolism Excretion and Toxicity (ADMET) properties. The results of molecular dynamics (MD) simulations, Principal component analysis (PCA), free energy landscape (FEL), dynamic cross-correlation matrix (DCCM) and molecular mechanics generalized Born Poisson-Boltzmann surface area (MM-PBSA) free energy calculations, revealed that the designed compounds were remained stable in protein binding pocket and compounds b ∼ f (-35.1 to -44.55 kcal/mol) showed higher binding free energy than that of compound 14 (-33.51 kcal/mol). The findings of this work will be a theoretical foundation for further research and experimental validation of urea/thiourea derivatives as hQC inhibitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The mycobacterial F-ATP synthase is responsible for the optimal growth, metabolism and viability of Mycobacteria, establishing it as a validated target for the development of anti-TB therapeutics. Herein, we report the discovery of an N-acyl phenothiazine derivative, termed PT6, targeting the mycobacterial F-ATP synthase. PT6 is bactericidal and active against the drug sensitive, Rifampicin-resistant as well as Multidrug-resistant tuberculosis strains. Compound PT6 showed noteworthy inhibition of F-ATP synthesis, exhibiting an IC 50 of 0.788 µM in M. smegmatis IMVs and was observed that it could deplete intracellular ATP levels, exhibiting an IC 50 of 30 µM. PT6 displayed a high selectivity towards mycobacterial ATP synthase compared to mitochondrial ATP synthase. Compound PT6 showed a minor synergistic effect in combination with Rifampicin and Isoniazid. PT6 demonstrated null cytotoxicity as confirmed by assessing its toxicity against VERO cell lines. Further, the binding mechanism and the activity profile of PT6 were validated by employing in silico techniques such as molecular docking, Prime MM/GBSA, DFT and ADMET analysis. These results suggest that PT6 presents an attractive lead for the discovery of a novel class of mycobacterial F-ATP synthase inhibitors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Sporadically and periodically, influenza outbreaks threaten global health and the economy. Antigen drift-induced influenza virus mutations hamper antiviral drug development. Thus, a novel antiviral agent is urgently needed to address medication inefficacy issues. Herein, sixteen new quinoline-triazole hybrids 6a-h and 9a-h were prepared and evaluated in vitro against the H1N1 virus. In particular, 6d, 6e, and 9b showed promising H1N1 antiviral activity with selective index (SI) CC 50 /IC 50 values of 15.8, 37, and 29.15. After that, the inhibition rates for various mechanisms of action (virus replication, adsorption, and virucidal activity) were investigated for the most efficient candidates 6d, 6e, and 9b. Additionally, their ability to inhibit neuraminidase was evaluated. With an IC 50 value of 0.30 µM, hybrid 6d demonstrated effective and comparable inhibitory activity to Oseltamivir. Ultimately, molecular modeling investigations, encompassing molecular docking and molecular dynamic simulations, were conducted to provide a scientific basis for the observed antiviral results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Design and virtual screening of a set of non-acidic 4-methyl-4-phenyl-benzenesulfonate-based aldose reductase 2 inhibitors had been developed followed by chemical synthesis. Based on the results, the synthesized compounds 2, 4a,b, 7a-c, 9a-c, 10a-c, 11b,c and 14a-c inhibited the ALR2 enzymatic activity in a submicromolar range (99.29-417 nM) and among them, the derivatives 2, 9b, 10a and 14b were able to inhibit ALR2 by IC 50 of 160.40, 165.20, 99.29 and 120.6 nM, respectively. Moreover, kinetic analyses using Lineweaver-Burk plot revealed that the most active candidate 10a inhibited ALR2 potently via a non-competitive mechanism. In vivo studies showed that 10 mg/kg of compound 10a significantly lowered blood glucose levels in alloxan-induced diabetic mice by 46.10 %. Moreover, compound 10a showed no toxicity up to a concentration of 50 mg/kg and had no adverse effects on liver and kidney functions. It significantly increased levels of GSH and SOD while decreasing MDA levels, thereby mitigating oxidative stress associated with diabetes and potentially attenuating diabetic complications. Furthermore, the binding mode of compound 10a was confirmed through MD simulation. Noteworthy, compounds 2 and 14b showed moderate antimicrobial activity against the two fungi Aspergillus fumigatus and Aspergillus niger. Finally, we report the thiazole derivative 10a as a new promising non-acidic aldose reductase inhibitor that may be beneficial in treating diabetic complications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Alismatis Rhizoma (AR), a traditional Chinese medicine for treating obesity in traditional Chinese medicine clinic, is recognized as a promising source of lead compounds of lipase inhibitors. Ultrafiltration centrifugal combined with liquid chromatography-mass spectrometry (UF-LC-MS) was used for screening potential lipase inhibitors from AR, and the result indicated the binding capacity between compound 7 and lipase (92.3 ± 1.28 %) was significantly higher than other triterpenoids, and was identified as alisol C 23-acetate. It exhibited a mixed-type inhibitory behavior with an IC 50 value of 84.88 ± 1.03 μM. Subsequently, the binding pockets of alisol C 23-acetate to lipase were predicted, and their binding mechanism was explored with molecular simulation. Pocket 1 (active center) and pocket 4 might be the orthosteric and allosteric binding sites of alisol C 23-acetate to lipase, respectively. The interaction between alisol C 23-acetate and lipase was identified to involve key amino acid residues such as GLY-77, PHE-78, TYR-115, LEU-154, PRO-181, PHE-216, LEU-264, ASP-278, GLN-306, ARG-313, and VAL-426. Meanwhile, alisol C 23-acetate remained stable during the intestinal digestive but degraded in the gastric digestion. Overall, alisol C 23-acetate is expected to be the lead compound of lipase inhibitors for treating obesity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Diabetic vascular complication including diabetic retinopathy is a major morbidity in Saudia Arabia. The polyol pathway aka aldose reductase (AR) pathway has gained significant association with diabetic retinopathy with regard to chronically enhanced glucose metabolism. Considerable research has been put forth to develop more effective therapeutic strategies to overcome the overwhelming challenges of vascular complications associated with diabetes. In this regard, constituents of Cichorium intybus can offer strong AR inhibitory potential because of their strong antidiabetic properties. Therefore, aim of this study was to investigate the AR inhibitory as well as antiglycation potential of C. intybus extract/compounds. The preliminary in vitro results showed that methanolic extract of C. intybus could significantly inhibit AR enzyme and advanced glycation end product formation. Eventually, based on previous studies and reviews, we selected one hundred fifteen C. intybus root constituents and screened them through Lipinski's rule of five and ADMET analysis. Later, after molecular docking analysis of eight compounds, five best were selected for molecular dynamics simulation to deduce their binding affinity with the AR enzyme. Finally, three out of five compounds were further tested in vitro for their AR inhibitory potential and antiglycation properties. Enzyme assay and kinetic studies showed that all the three tested compounds were having potent AR inhibitory properties, although to a lesser extent than ellagic acid and tolrestat. Similarly, kaempferol showed strong antiglycation property equivalent to ellagic acid, but greater than aminoguanidine. Intriguingly, significant reduction in sorbitol accumulation in RBCs by the tested compounds substantiated strong AR inhibition by these compounds. Moreover, decrease in sorbitol accumulation under high glucose environment also signifies the potential application of these compounds in diabetic retinopathy and other vascular complications. Thus, in sum, the in silico and in vitro studies combinedly showed that C. intybus root is a treasure for therapeutic compounds and can be explored further for drug development against diabetic retinopathy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The increasing prevalence of drug-resistant Mycobacterium tuberculosis strains stimulates the discovery of new drug candidates. Among them are 8-hydroxyquinoline (8HQ) derivatives that exhibited antimicrobial properties. Unfortunately, there is a lack of data assessing possible targets for this class mainly against Mycobacterium tuberculosis enoyl-acyl carrier protein reductase (MtInhA), a validated target in this field. Thus, the main purpose of this study was to identify 8HQ derivatives that are active against M. tuberculosis and MtInhA. Initially, the screening against the microorganism of a small antimicrobial library and its new derivatives that possess some structural similarity with MtInhA inhibitors identified four 7-substituted-8HQ (series 5 - 5a, 5c, 5d and 5i) and four 5-substituted-8HQ active derivatives (series 7 - 7a, 7c, 7d and 7j). In general, the 7-substituted 8-HQs were more potent and, in the enzymatic assay, were able to inhibit MtInhA at low micromolar range. However, the 5-substituted-8-HQs that presented antimycobacterial activity were not able to inhibit MtInhA. These findings indicate the non-promiscuous nature of 8-HQ derivatives and emphasize the significance of selecting appropriate substituents to achieve in vitro enzyme inhibition. Finally, 7-substituted-8HQ series are promising new derivatives for structure-based drug design and further development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Dysregulation of peptidyl arginine deiminase 4 (PAD4) is involved in a variety of diseases including rheumatoid arthritis (RA) and Alzheimer's disease (AD), and it has emerged as potential and promising therapeutic target. However, no PAD4 inhibitor is ready for clinical use. Immobilized enzyme screening technology has gained increasing attention due to its low cost, reusability, easy separation from the reaction mixture, and resistance to changes in environmental conditions. In this study, PAD4 was immobilized on the magnetic nanoparticles (MNP) to prolong its activity stability, and a simple and rapid screening strategy of traditional Chinese medicine inhibitors based on immobilized PAD4 was established. The PAD4 enzyme was immobilized on magnetic nanoparticles (MNP) via Schiff base reaction using glutaraldehyde (GA) as crosslinking agent. Compared with free PAD4, the resulting MNP@GA@PAD4 exhibited an enhanced tolerance to temperature and storage stability, and its reusability was greatly improved with 66 % of initial enzyme activity after being recycled 10 times. The inhibitory activity of the immobilized PAD4 was assessed using two known PAD4 inhibitors GSK484 and BB-Cl-amidine. The semi-maximum inhibitory concentrations (IC 50 ) of GSK484 and BB-Cl-amidine for MNP@GA@PAD4 were 1.00 and 0.97 μM, respectively, for free PAD4 were 0.64 and 0.85 μM, respectively. Finally, the MNP@GA@PAD4 was employed to rapid screen of natural PAD4 inhibitors from forty traditional Chinese medicines (TCMs). Under the same conditions, the controlled experiment was conducted with free PAD4. The screening results of TCMs inhibitors on MNP@GA@PAD4 and free PAD4 were similar, the alcohol extracts of Cinnamomi Cortex and Caryophylli Flos had significant inhibitory effects on PAD4 enzyme activity. The IC 50 values of Cinnamomi Cortex extract for MNP@GA@PAD4 and free PAD4 were determined as 27 and 48 μg/mL, respectively. The IC 50 values of Caryophylli Flos extracts for MNP@GA@PAD4 and free PAD4 were determined as 48 and 32 μg/mL, respectively. For the first time, this study proposed a method to immobilize PAD4 on magnetic materials, and developed a rapid, reusable and feasible strategy to screening natural PAD4 inhibitors from TCMs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Acetyl-coenzyme A carboxylase (ACC) and diacylglycerol acyltransferase 2 (DGAT2) are recognized as potential therapeutic targets for nonalcoholic fatty liver disease (NAFLD). Inhibitors targeting ACC and DGAT2 have exhibited the capacity to reduce hepatic fat in individuals afflicted with NAFLD. However, there are no reports of dual inhibitors targeting ACC and DGAT2 for the treatment of NAFLD. Here, we aimed to identify potential dual inhibitors of ACC and DGAT2 using an integrated in silico approach. Machine learning-based virtual screening of commercial molecule databases yielded 395,729 hits, which were subsequently subjected to molecular docking aimed at both the ACC and DGAT2 binding sites. Based on the docking scores, nine compounds exhibited robust interactions with critical residues of both ACC and DGAT2, displaying favorable drug-like features. Molecular dynamics simulations (MDs) unveiled the substantial impact of these compounds on the conformational dynamics of the proteins. Furthermore, binding free energy assessments highlighted the notable binding affinities of specific compounds (V003-8107, G340-0503, Y200-1700, E999-1199, V003-6429, V025-4981, V006-1474, V025-0499, and V021-8916) to ACC and DGAT2. The compounds proposed in this study, identified using a multifaceted computational strategy, warrant experimental validation as potential dual inhibitors of ACC and DGAT2, with implications for the future development of novel drugs targeting NAFLD., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

During the search for protein tyrosine phosphatase 1B (PTP1B) inhibitory compounds from the natural resources, two new serratane triterpenes, 3-O-dihydro-p-coumaroyltohogenol (1) and 21-O-acetyltohogenol (2), along with four known serratane triterpenes (3-6), were isolated from the whole plant of Huperzia serrata. The chemical structures of compounds 1 and 2 were determined by NMR study, HRMS analysis, and chemical modification. All isolates were evaluated for their PTP1B inhibitory activities. Among the isolates, compounds 1, 3, 5 and 6 exhibit moderate inhibitory activities against PTP1B. Kinetic studies demonstrated that they are competitive inhibitors. Molecular docking studies support these experimental results by showing that compounds 1, 3, 5 and 6 interact with the active site of PTP1B, clarifying the structure-activity relationship. This study suggests that serratane triterpenes from H. serrata have potential as starting skeletons for anti-diabetes or anti-obesity agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The discovery of enzyme inhibitors from natural products is a crucial aspect in the development of therapeutic drugs. However, the complexity of natural products presents a challenge in developing simple and efficient methods for inhibitor screening. Herein, we have developed an integrated analytical model for screening xanthine oxidase (XOD) inhibitors that combines simplicity, accuracy, and efficiency. This model utilizes a colorimetric sensor and affinity chromatography technology with immobilized XOD. The colorimetric sensor procedure can quickly identify whether there are active components in complex samples. Subsequently, the active components in the samples identified by the colorimetric sensor procedure were further captured, separated, and identified through affinity chromatography. The integrated analytical model can significantly enhance the efficiency and accuracy of inhibitor screening. The proposed method was applied to screen for an activity inhibitor of XOD in five natural medicines. As a result, a potential active ingredient for XOD, polydatin, was successfully identified from Polygoni Cuspidati Rhizoma et Radix. This work is anticipated to offer new insights for the screening of enzyme inhibitors from natural medicines., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Glutamate dehydrogenases (GDHs) are key enzymes at the crossroads of N and C metabolism in plants. Legumes, whose N metabolism is particularly intricate, possess a unique type of GDH. This study presents an analysis of a legume-type GDH (isoform 2) from Medicago truncatula (MtGDH2). We measured MtGDH2 activity in both the Glu → 2-oxoglutarate (2OG) and 2OG → Glu reaction directions and obtained kinetic parameters for Glu, 2OG, NAD + , and NADH. Inhibition assays revealed that compounds possessing di- or tricarboxylates act as inhibitors of plant GDHs. Interestingly, 2,6-pyridinedicarboxylate (PYR) weakly inhibits MtGDH2 compared to Arabidopsis thaliana homologs. Furthermore, we explored tetrazole derivatives to discover 3-(1H-tetrazol-5-yl)benzoic acid (TBA) as an MtGDH2 inhibitor. The kinetic experiments are supported by six crystal structures, solved as: (i) unliganded enzyme, (ii) trapping the reaction intermediate 2-amino-2-hydroxyglutarate and NAD + , and also complexed with NAD + and inhibitors such as (iii) citrate, (iv) PYR, (v) isophthalate, and (vi) TBA. The complex with TBA revealed a new mode of action that, in contrast to other inhibitors, prevents domain closure. This discovery points to TBA as a starting point for the development of novel GDH inhibitors to study the functions of GDH in plants and potentially boost biomass production., Competing Interests: Declaration of competing interest Milosz Ruszkowski reports financial support was provided by National Science Centre Poland. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In 1958, the presence of citrulline in the structure of the proteins was discovered for the first time. Several years later they found that Arginine converted to citrulline during a post-translational modification process by PAD enzyme. Each PAD is expressed in a certain tissue developing a series of diseases such as inflammation and cancers. Among these, PAD2 and PAD4 play a role in the development of rheumatoid arthritis (RA) by producing citrullinated autoantigens and increasing the production of inflammatory cytokines. PAD4 is also associated with the formation of NET structures and thrombosis. In the crystallographic structure, PAD has several calcium binding sites, and the active site of the enzyme consists of different amino acids. Various PAD inhibitors have been developed divided into pan-PAD and selective PAD inhibitors. F-amidine, Cl-amidine, and BB-Cl-amidine are some of pan-PAD inhibitors. AFM-30a and JBI589 are selective for PAD2 and PAD4, respectively. There is a need to evaluate the effectiveness of existing inhibitors more accurately in the coming years, as well as design and production of novel inhibitors targeting highly specific isoforms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The discovery and development of structurally distinct lysine methyltransferase G9a inhibitors have been the subject of intense research in epigenetics. Structure-based optimization was conducted, starting with the previously reported seed compound 7a and lead to the identification of a highly potent G9a inhibitor, compound 7i (IC 50  = 0.024 μM). X-ray crystallography for the ligand-protein interaction and kinetics study, along with surface plasmon resonance (SPR) analysis, revealed that compound 7i interacts with G9a in a unique binding mode. In addition, compound 7i caused attenuation of cellular H3K9me2 levels and induction of γ-globin mRNA expression in HUDEP-2 cells in a dose-dependent manner., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Y.N., T. Su., N.H., R.N., M.Y., A.I., and F.S. are listed as inventors on a PCT international patent application (WO/2021/106988) that covers compound 7i, a compound studied in this paper. The remaining authors declare no conflicts of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Broussonetine S (9), its C-1' and C-10' stereoisomers, and their corresponding enantiomers have been synthesized from enantiomeric arabinose-derived cyclic nitrones, with cross metathesis (CM), epoxidation and Keck asymmetric allylation as key steps. Glycosidase inhibition assays showed that broussonetine S (9) and its C-10' epimer (10'-epi-9) were nanomolar inhibitors of bovine liver β-galactosidase and β-glucosidase; while their C-1' stereoisomers were 10-fold less potent towards these enzymes. The glycosidase inhibition results and molecular docking calculations revealed the importance of the configurations of pyrrolidine core and C-1' hydroxyl for inhibition potency and spectra. Together with the docking calculations we previously reported for α-1-C-alkyl-DAB derivatives, we designed and synthesized a series of 6-C-alkyl-DMDP derivatives with very simple alkyl chains. The inhibition potency of these derivatives was enhanced by increasing the length of the side chain, and maintained at nanomolar scale inhibitions of bovine liver β-glucosidase and β-galactosidase after the alkyl groups are longer than eight or ten carbons for the (6R)-C-alkyl-DMDP derivatives and their 6S epimers, respectively. Molecular docking calculations indicated that each series of 6-C-alkyl-DMDP derivatives resides in the same active site of β-glucosidase or β-galactosidase with basically similar binding conformations, and their C-6 long alkyl chains extend outwards along the hydrophobic groove with similar orientations. The increasing inhibitions of β-glucosidase and β-galactosidase with the number of carbon atoms in the side chains may be explained by improved adaptability of longer alkyl chains in the hydrophobic grooves. In addition, the lower β-glucosidase and β-galactosidase inhibitions of (6S)-C-alkyl-DMDP derivatives than their C-6 R stereoisomers can be attributed to the misfolding of their alkyl chains and resulted decreased adaptability in the hydrophobic groove. The work reported herein is valuable for design and development of more potent and selective inhibitors of β-galactosidase and β-glucosidase, which have potential in treatment of lysosomal storage diseases. Furthermore, part of the 6-C-alkyl-DMDP derivatives and their enantiomers were also tested as potential anti-cancer agents; all the compounds tested were found with moderate cytotoxic effects on MKN45 cells, which would indicate potential applications of these iminosugars in development of novel anticancer agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

SHP2 is a non-receptor tyrosine phosphatase encoded by PTPN11, which performs the functions of regulating cell proliferation, differentiation, apoptosis, and survival through removing tyrosine phosphorylation and modulating various signaling pathways. The overexpression of SHP2 or its mutations is related to developmental diseases and several cancers. Numerous allosteric inhibitors with striking inhibitory potency against SHP2 allosteric pockets have recently been identified, and several SHP2 tunnel allosteric inhibitors have been applied in clinical trials to treat cancers. However, based on clinical results, the efficacy of single-agent treatments has been proven to be suboptimal. Most clinical trials involving SHP2 inhibitors have adopted drug combination strategies. This review briefly discusses the research progress on SHP2 allosteric inhibitors and pathway-dependent drug combination strategies for SHP2 in cancer therapy. In addition, we summarize the current bifunctional molecules of SHP2 and elaborate on the design and structural optimization strategies of these bifunctional molecules in detail, offering further direction for the research on novel SHP2 inhibitors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Mutations in IDH1 are commonly observed across various cancers, causing the conversion of α-KG to 2-HG. Elevated levels of 2-HG disrupt histone and DNA demethylation processes, promoting tumor development. Consequently, there is substantial interest in developing small molecule inhibitors targeting the mutant enzymes. Herein, we report a structure-based high-throughput virtual screening strategy using a natural products library, followed by hit-to-lead optimization. Through this process, we discover a potent compound, named 11s, which exhibited significant inhibition to IDH1 R132H and IDH1 R132C with IC 50 values of 124.4 and 95.7 nM, respectively. Furthermore, 11s effectively reduced 2-HG formation, with EC 50 values of 182 nM in U87 R132H cell, and 84 nM in HT-1080 cell. In addition, 11s significantly reduced U87 R132H and HT-1080 cell proliferation with GC 50 values of 3.48 and 1.38 μM, respectively. PK-PD experiments further confirmed that compound 11s significantly decreased 2-HG formation in an HT-1080 xenograft mouse model, resulting in notable suppression of tumor growth without apparent loss in body weight., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Background: As a significant biomarker of melanocytic lesions, tyrosinase (TYR) plays an essential role in the clinical diagnosis and treatment of melanin-related diseases. Thus, it is important to develop robust methods for assessing TYR activity. Covalent organic frameworks (COFs) have garnered considerable attention owing to their unique properties, including high chemical stability, good biocompatibility, and large surface area compared with organic dyes, noble metal nanoclusters, and semiconductor quantum dots. However, most COFs are insoluble in water and exhibit weak or no fluorescence emission. Therefore, the development of a water-soluble fluorescent COF for detecting TYR activity in biological samples remains highly desired., Results: In this work, a sensitive and facile fluorometric method based on fluorescent COF was constructed for the detection of TYR activity in human serum samples. The water-soluble COF was fabricated through the condensation polymerization of 4',4‴,4''''',4'''''''-(1,2-ethene-diylidene) tetrakis [1,1'-biphenyl]-4-carboxaldehyde and 2,4,6-tris-(4-aminophenyl)-triazine. The resulting COF displayed yellow-green fluorescence with a maximum emission peak at 560 nm. Tyrosine was catalyzed by TYR to produce melanin-like polymers which formed a coating on the surface of COF and effectively quenched its fluorescence due to fluorescence resonance energy transfer. The proposed approach demonstrated a strong linear correlation in the range of 0.5-80 U/L with a low detection limit of 0.09 U/L. Additionally, the limit of detection for kojic acid, serving as a representative TYR inhibitor, was determined to be 0.0004 μg/mL., Significance: Our proposed fluorometric sensing platform exhibited exceptional selectivity, sensitivity, and satisfactory recoveries in human serum samples, which is of paramount importance for the clinical diagnostics of melanin-related diseases. Furthermore, the proposed approach was further employed for the screening of TYR inhibitors, suggesting the potential applications in clinical treatment and pharmaceutical research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

DNA methylation can deactivate tumor suppressor genes thus causing cancers. Two DNA methylation inhibitors have been approved by the Food and Drug Administration (FDA) and have entered clinical use. However, these inhibitors are nucleoside analogues that can be incorporated into DNA or RNA and induce significant side effects. DNMT1 and DNMT3 are key enzymes involved in DNA methylation. In the acute myeloid leukemia model, a non-nucleoside DNMT1-specific inhibitor has shown lower toxicity and improved pharmacokinetics compared to traditional nucleoside drugs. DNMT3 is also implicated in certain specific cancers. Thus, developing non-nucleoside inhibitors for DNMT1 or DNMT3 can help in understanding their roles in carcinogenesis and provide targeted treatment options in certain cancers. Although no non-nucleoside inhibitors have yet entered clinical trials, in this review, we focus on DNMT1 or DNMT3 selective inhibitors. For DNMT1 selective inhibitors, we have compiled information on the repurposed drugs, derivative compounds and selective inhibitors identified through virtual screening. Additionally, we have outlined potential targets for DNMT1, including protein-protein complex, RNA mimics and aptamers. Compared to DNMT1, research on DNMT3-specific inhibitors has been less extensive. In this context, our exploration has identified a limited number of molecular inhibitors, and we have proposed specific long non-coding RNAs (lncRNAs) as potential contributors to the selective inhibition of DNMT3. This collective effort aims to offer valuable insights into the development of non-nucleoside inhibitors that selectively target DNMT1 or DNMT3., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)