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This study focused on identifying and characterizing 1,3-diphenylpropane derivatives from flavonoids that inhibit human indoleamine 2,3-dioxygenase 1 (hIDO1) enzymes, which play a role in immune regulation and are associated with various diseases. A series of isolated metabolites (1–7) demonstrated modest to high inhibition of hIDO1, with binding degree values ranging from 26.31 to 72.17%. In particular, during a target-based screening of natural products using hIDO1, kazinol J (6, a 1,3-diphenylpropane derivative) was found to potently inhibit hIDO1, with a binding degree of 72.17% at 1 ppm. Kazinol J (6) showed concentration-dependent and mixed inhibition kinetics and achieved slow and time-dependent inhibition of hIDO1. Additionally, docking simulations were performed to evaluate the inhibitory potential and binding interactions of the compounds with hIDO1. These findings suggest that these 1,3-diphenylpropane derivatives can serve as therapeutic agents for conditions involving hIDO1 dysregulation, such as cancer, autoimmune disorders, and infectious diseases. [ABSTRACT FROM AUTHOR]

The interaction between linamarin (LIN), a cyanogenic glycoside, and human serum albumin (HSA) was studied by multiple spectroscopic techniques and molecular docking simulation. All measurements were performed under physiological conditions. The obtained results (including the binding constants, effective quenching constant and a number of binding sites) showed that the complex of HSA‐LIN is formed. The values of Stern‐Volmer constants (6.70×103, 5.53×103 and 1.95×103) indicate that fluorescence quenching of HSA was static. Results of site marker experiments showed that the binding site of LIN is mainly located in site I (subdomain IIA) of HSA. The thermodynamic parameters showed that binding process occurs spontaneously through hydrophobic interactions. Molecular docking results are in good agreement with experimental data. Furthermore, computational results revealed LIN binds in the cavity of TRP 214, that is, subdomain IIA (site I) of HSA. This comprehensive study provides a deeper insight into ligand binding in HSA which may be useful in drug design and pharmacology. [ABSTRACT FROM AUTHOR]

Currently, one-third of global food production, accounting for 1.3 billions tons, goes wasted due to major humanitarian and environmental challenges. In such a scenario, the circular bioeconomy model stands as an innovative solution by promoting sustainable production, utilizing agri-food waste, and converting non-renewable products into valuable resources. Here, the circular bioeconomy concept was applied on a previously obtained chestnut burr extract (agri-food waste) composed of gallic acid, quinic acid, protocatechuic acid, brevifolin carboxylic acid, and ellagic acid to evaluate its antimicrobial activity against four bacterial opportunistic pathogens (Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli). Our results evidenced a modest but measurable antibacterial activity against Enterococcus faecalis, with a minimum inhibitory concentration (MIC) of 64 μg/mL. In silico studies allowed for identifying the potential molecular target, supporting the underlying antibacterial activity of the active principle and providing useful molecular findings regarding their interaction. In this study, we show a robust and comprehensive in vitro and in silico pipeline aimed at the identification of novel antibacterial scaffolds taking advantage of agri-food waste. [ABSTRACT FROM AUTHOR]

Researchers are increasingly interested in discovering new pancreatic lipase inhibitors as anti-obesity ingredients. Medicine-and-food homology plants contain a diverse set of natural bioactive compounds with promising development potential. This study screened and identified potent pancreatic lipase inhibitors from 20 commonly consumed medicine-and-food homology plants using affinity ultrafiltration combined with spectroscopy and docking simulations. The results showed that turmeric exhibited the highest pancreatic lipase-inhibitory activity, and curcumin, demethoxycurcumin, and bisdemethoxycurcumin were discovered to be potent pancreatic lipase inhibitors within the turmeric extract, with IC50 values of 0.52 ± 0.04, 1.12 ± 0.05, and 3.30 ± 0.08 mg/mL, respectively. In addition, the enzymatic kinetics analyses demonstrated that the inhibition type of the three curcuminoids was the reversible competitive model, and curcumin exhibited a higher binding affinity and greater impact on the secondary structure of pancreatic lipase than found with demethoxycurcumin or bisdemethoxycurcumin, as observed through fluorescence spectroscopy and circular dichroism. Furthermore, docking simulations supported the above experimental findings, and revealed that the three curcuminoids might interact with amino acid residues in the binding pocket of pancreatic lipase through non-covalent actions, such as hydrogen bonding and π-π stacking, thereby inhibiting the pancreatic lipase. Collectively, these findings suggest that the bioactive compounds of turmeric, in particular curcumin, can be promising dietary pancreatic lipase inhibitors for the prevention and management of obesity. [ABSTRACT FROM AUTHOR]

Abstract This study focused on identifying and characterizing 1,3-diphenylpropane derivatives from flavonoids that inhibit human indoleamine 2,3-dioxygenase 1 (hIDO1) enzymes, which play a role in immune regulation and are associated with various diseases. A series of isolated metabolites (1–7) demonstrated modest to high inhibition of hIDO1, with binding degree values ranging from 26.31 to 72.17%. In particular, during a target-based screening of natural products using hIDO1, kazinol J (6, a 1,3-diphenylpropane derivative) was found to potently inhibit hIDO1, with a binding degree of 72.17% at 1 ppm. Kazinol J (6) showed concentration-dependent and mixed inhibition kinetics and achieved slow and time-dependent inhibition of hIDO1. Additionally, docking simulations were performed to evaluate the inhibitory potential and binding interactions of the compounds with hIDO1. These findings suggest that these 1,3-diphenylpropane derivatives can serve as therapeutic agents for conditions involving hIDO1 dysregulation, such as cancer, autoimmune disorders, and infectious diseases.

The concept of a "circular bioeconomy" holds great promise for the health, cosmetic, and nutrition sectors by re-using Castanea sativa (Mill.) by-products. This sustainable resource is rich in bioactive secondary metabolites with antioxidant and anti-inflammatory properties. By transforming these by-products into high-value products for human health, we can promote sustainable economic growth and reduce the environmental impact of traditional waste disposal, adding value to previously underutilized resources. In the present study, we investigated the antioxidant capacity, phytochemical composition, and in vitro antioxidant and anti-inflammatory activity of C. sativa burr (CSB) aqueous extract. The spectrophotometric study revealed high total phenolic content (TPC) values with significant antioxidant and anti-radical properties. Using UPLC-MS/MS techniques, the phytochemical investigation identified 56 metabolites, confirming the presence of phenolic compounds in CSBs. In addition, CSBs significantly downregulated pro-inflammatory mediators in LPS-stimulated RAW 264.7 macrophage cells without significant cell toxicity. Lastly, in silico studies pinpointed three kinases from RAW 264.7 cells as binding partners with ellagic acid, the predominant compound found in our extract. These findings strongly advocate for the recycling and valorization of C. sativa by-products, challenging their conventional classification as mere "waste". [ABSTRACT FROM AUTHOR]

The emergence of multi-drug-resistant autoimmune diseases poses a significant risk to human health and has garnered global attention. In this study, metformin and sulfasalazine have been used as starting materials or control. This research has successfully designed a hundred compounds, to assess their efficacy against two autoimmune disease pathogens: type 1 diabetes and rheumatoid arthritis. The DFT method was engaged to calculate the vibrational frequencies and Frontier Molecular orbitals (FMOs) of the selected compounds. The reactivity and selectivity of the selected compounds are analyzed using parameters like MEP and global reactivity descriptors, which are calculated and interpreted. The Density of state (DOS) of the molecule has been plotted and interpreted. Furthermore, docking results showed favorable interactions of the designed compound D385 with catalytically important amino acid residues. The interactions of the best active D385 when compared with the template and the standard drugs show similar binding sites. DFT studies further confirm the presence of HOMO orbital centered on the isoxazole ring further highlighting its importance for receptor-ligand hydrogen and hydrophobic interactions. The molecular dynamics simulations and MM/GBSA analysis reveal that the inhibitory nature of the designed compound D385 is a proven inhibitor of diabetes type 1 and rheumatoid arthritis inhibitor activities. Our study suggested that the designed compounds showed comparable results to that of metformin and sulfasalazine and may be used for further experimental studies. It can also be used as a pipeline to search for and design new potential autoimmune disease inhibitors. The most promising candidates from computational trials can be examined in a wet laboratory experiment before moving on to clinical trials. [ABSTRACT FROM AUTHOR]

Molecular docking of a large set of thiosemicarbazide-based ligands resulted in obtaining compounds that inhibited both human DNA topoisomerase IIα and indoleamine-2,3-dioxygenase-1 (IDO1). To the best of our knowledge, these compounds are the first dual inhibitors targeting these two enzymes. As both of them participate in the anticancer response, the effect of the compounds on a panel of cancer cell lines was examined. Among the cell lines tested, lung cancer (A549) and melanoma (A375) cells were the most sensitive to compounds 1 (IC50=0.23 µg/ml), 2 (IC50=0.83 µg/ml) and 3 (IC50=0.25 µg/ml). The observed activity was even 90-fold higher than that of etoposide, with selectivity index values reaching 125. In-silico simulations showed that contact between 1-3 and human DNA topoisomerase II was maintained through aromatic moieties located at limiting edges of ligand molecules and intensive interactions of the thiosemicarbazide core with the DNA fragments present in the catalytic site of the enzyme.

Researchers are increasingly interested in discovering new pancreatic lipase inhibitors as anti-obesity ingredients. Medicine-and-food homology plants contain a diverse set of natural bioactive compounds with promising development potential. This study screened and identified potent pancreatic lipase inhibitors from 20 commonly consumed medicine-and-food homology plants using affinity ultrafiltration combined with spectroscopy and docking simulations. The results showed that turmeric exhibited the highest pancreatic lipase-inhibitory activity, and curcumin, demethoxycurcumin, and bisdemethoxycurcumin were discovered to be potent pancreatic lipase inhibitors within the turmeric extract, with IC50 values of 0.52 ± 0.04, 1.12 ± 0.05, and 3.30 ± 0.08 mg/mL, respectively. In addition, the enzymatic kinetics analyses demonstrated that the inhibition type of the three curcuminoids was the reversible competitive model, and curcumin exhibited a higher binding affinity and greater impact on the secondary structure of pancreatic lipase than found with demethoxycurcumin or bisdemethoxycurcumin, as observed through fluorescence spectroscopy and circular dichroism. Furthermore, docking simulations supported the above experimental findings, and revealed that the three curcuminoids might interact with amino acid residues in the binding pocket of pancreatic lipase through non-covalent actions, such as hydrogen bonding and π-π stacking, thereby inhibiting the pancreatic lipase. Collectively, these findings suggest that the bioactive compounds of turmeric, in particular curcumin, can be promising dietary pancreatic lipase inhibitors for the prevention and management of obesity.

Marine compounds constitute a diverse and invaluable resource for the discovery of bioactive substances with promising applications in the pharmaceutical development of anti-inflammatory and antibacterial agents. In this study, a comprehensive methodology was employed, encompassing pharmacophore modeling, virtual screening, in silico ADMET assessment (encompassing aspects of absorption, distribution, metabolism, excretion, and toxicity), and molecular dynamics simulations. These methods were applied to identify new inhibitors targeting the Hsp90 protein (heat shock protein 90), commencing with a diverse assembly of compounds sourced from marine origins. During the virtual screening phase, an extensive exploration was conducted on a dataset comprising 31,488 compounds sourced from the CMNPD database, characterized by a wide array of molecular structures. The principal objective was the development of structure-based pharmacophore models, a valuable approach when the pool of known ligands is limited. The pharmacophore model DDRRR was successfully constructed within the active sites of the Hsp90 crystal structure. Subsequent docking studies led to the identification of six compounds (CMNPD 22591, 9335, 10015, 360799, 15115, and 20988) demonstrating substantial binding affinities, each with values below −8.3 kcal/mol. In the realm of in silico ADMET predictions, five of these compounds exhibited favorable pharmacokinetic properties. Furthermore, molecular dynamics simulations and total binding energy calculations using MM-PBSA indicated that these marine-derived compounds formed exceptionally stable complexes with the Hsp90 receptor over a 100-nanosecond simulation period. These findings underscore the considerable potential of these novel marine compounds as promising candidates for anticancer and antimicrobial drug development. [ABSTRACT FROM AUTHOR]

Molecular docking of a large set of thiosemicarbazide-based ligands resulted in obtaining compounds that inhibited both human DNA topoisomerase IIα and indoleamine-2,3-dioxygenase-1 (IDO1). To the best of our knowledge, these compounds are the first dual inhibitors targeting these two enzymes. As both of them participate in the anticancer response, the effect of the compounds on a panel of cancer cell lines was examined. Among the cell lines tested, lung cancer (A549) and melanoma (A375) cells were the most sensitive to compounds 1 (IC50=0.23 µg/ml), 2 (IC50=0.83 µg/ml) and 3 (IC50=0.25 µg/ml). The observed activity was even 90-fold higher than that of etoposide, with selectivity index values reaching 125. In-silico simulations showed that contact between 1-3 and human DNA topoisomerase II was maintained through aromatic moieties located at limiting edges of ligand molecules and intensive interactions of the thiosemicarbazide core with the DNA fragments present in the catalytic site of the enzyme. [ABSTRACT FROM AUTHOR]

Currently, one-third of global food production, accounting for 1.3 billions tons, goes wasted due to major humanitarian and environmental challenges. In such a scenario, the circular bioeconomy model stands as an innovative solution by promoting sustainable production, utilizing agri-food waste, and converting non-renewable products into valuable resources. Here, the circular bioeconomy concept was applied on a previously obtained chestnut burr extract (agri-food waste) composed of gallic acid, quinic acid, protocatechuic acid, brevifolin carboxylic acid, and ellagic acid to evaluate its antimicrobial activity against four bacterial opportunistic pathogens (Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli). Our results evidenced a modest but measurable antibacterial activity against Enterococcus faecalis, with a minimum inhibitory concentration (MIC) of 64 μg/mL. In silico studies allowed for identifying the potential molecular target, supporting the underlying antibacterial activity of the active principle and providing useful molecular findings regarding their interaction. In this study, we show a robust and comprehensive in vitro and in silico pipeline aimed at the identification of novel antibacterial scaffolds taking advantage of agri-food waste.

The LC3 proteins play a crucial role in autophagy by participating to the formation of the autophagosome. Modulation of autophagy by molecular interference with LC3 proteins could help to understand this complex fundamental biological process and how it is involved in several pathologies. Identifying new LC3 ligands is a useful contribution to this aim. In the present study, we created a PubChem library of 749 compounds having a structure based on the central scaffold of novobiocin, a reported LC3A ligand. A robust, rapid and exhaustive algorithm was used for docking each compound of this database as ligands within the dihydronovobiocin binding site, providing a docking score. Remarkable reliability and consistency between docking scores and the reported binding efficiencies of known ligands was observed, validating the machine leaning protocol used in this study. Investigation of the binding mode of the ligands having the best docking score provides additional insights in possible mode of actions of the LC3 identified ligands.

N-ferrocenylmethylaniline (FA) and its N-acetylated derivative (NFA) have been synthesized and fully characterized by various physicochemical techniques such as 1H and 13C NMR spectroscopy, their interactions with chicken blood DNA (CB-DNA) were studied by cyclic voltammetry (CV) and molecular docking (MD). The obtained results suggested that both FA and NFA bind strongly via electrostatic interactions to the minor groove of double helix DNA, these electrostatic interactions were evidenced by the findings like a negative formal potential shift in CV and ionic strength effect. The results further show that the obtained binding constants and free binding energies by MD analysis are matched roughly to those obtained from CV. Furthermore, the binding site size was evaluated from voltametric data.

Background: Specific interactions between G protein-coupled receptors (GPCRs) and G proteins play a key role in mediating signaling events. While there is little doubt regarding receptor preference for Gα subunits, the preferences for specific Gβ and Gγ subunits and the effects of different Gβγ dimer compositions on GPCR signaling are poorly understood. In this study, we aimed to investigate the subcellular localization and functional response of Gαi3-based heterotrimers with different combinations of Gβ and Gγ subunits. Methods: Live-cell imaging microscopy and colocalization analysis were used to investigate the subcellular localization of Gαi3 in combination with Gβ1 or Gβ2 heterotrimers, along with representative Gγ subunits. Furthermore, fluorescence lifetime imaging microscopy (FLIM-FRET) was used to investigate the nanoscale distribution of Gαi3-based heterotrimers in the plasma membrane, specifically with the dopamine D2 receptor (D2R). In addition, the functional response of the system was assessed by monitoring intracellular cAMP levels and conducting bioinformatics analysis to further characterize the heterotrimer complexes. Results: Our results show that Gαi3 heterotrimers mainly localize to the plasma membrane, although the degree of colocalization is influenced by the accompanying Gβ and Gγ subunits. Heterotrimers containing Gβ2 showed slightly lower membrane localization compared to those containing Gβ1, but certain combinations, such as Gαi3β2γ8 and Gαi3β2γ10, deviated from this trend. Examination of the spatial arrangement of Gαi3 in relation to D2R and of changes in intracellular cAMP level showed that the strongest functional response is observed for those trimers for which the distance between the receptor and the Gα subunit is smallest, i.e. complexes containing Gβ1 and Gγ8 or Gγ10 subunit. Deprivation of Gαi3 lipid modifications resulted in a significant decrease in the amount of protein present in the cell membrane, but did not always affect intracellular cAMP levels. Conclusion: Our studies show that the composition of G protein heterotrimers has a significant impact on the strength and specificity of GPCR-mediated signaling. Different heterotrimers may exhibit different conformations, which further affects the interactions of heterotrimers and GPCRs, as well as their interactions with membrane lipids. This study contributes to the understanding of the complex signaling mechanisms underlying GPCR-G-protein interactions and highlights the importance of the diversity of Gβ and Gγ subunits in G-protein signaling pathways. C8a11hmRuxdWs3DubYRKG2 Video Abstract [ABSTRACT FROM AUTHOR]

The affinity of specific phenolic compounds (PCs) and capsaicinoids (CAPs) present in three Capsicum annuum varieties (Friariello, Cayenne and Dzuljunska Sipka) to the transient receptor potential vanilloid member 1 (TRPV1) was investigated by integrating an analytic approach for the simultaneous extraction and analysis through high-performance liquid chromatography coupled with ion trap mass spectrometry (HPLC/ITMS) and UV detection (HPLC-UV) of PCs and CAPs and structural bioinformatics based on the protein modelling and molecular simulations of protein–ligand docking. Overall, a total of 35 compounds were identified in the different samples and CAPs were quantified. The highest content of total polyphenols was recorded in the pungent Dzuljunska Sipka variety (8.91 ± 0.05 gGAE/Kg DW) while the lowest was found in the non-pungent variety Friariello (3.58 ± 0.02 gGAE/Kg DW). Protein modelling generated for the first time a complete model of the homotetrameric human TRPV1, and it was used for docking simulations with the compounds detected via the analytic approach, as well as with other compounds, as an inhibitor reference. The simulations indicate that different capsaicinoids can interact with the receptor, providing details on the molecular interaction, with similar predicted binding energy values. These results offer new insights into the interaction of capsaicinoids with TRPV1 and their possible actions. [ABSTRACT FROM AUTHOR]

Pentagalloyl glucose (PGG) is currently being investigated as a non-surgical treatment for abdominal aortic aneurysms (AAAs); however, the molecular mechanisms of action of PGG on the AAA matrix components and the intra-luminal thrombus (ILT) still need to be better understood. To assess these interactions, we utilized peptide fingerprinting and molecular docking simulations to predict the binding of PGG to vascular proteins in normal and aneurysmal aorta, including matrix metalloproteinases (MMPs), cytokines, and fibrin. We performed PGG diffusion studies in pure fibrin gels and human ILT samples. PGG was predicted to bind with high affinity to most vascular proteins, the active sites of MMPs, and several cytokines known to be present in AAAs. Finally, despite potential binding to fibrin, PGG was shown to diffuse readily through thrombus at physiologic pressures. In conclusion, PGG can bind to all the normal and aneurysmal aorta protein components with high affinity, potentially protecting the tissue from degradation and exerting anti-inflammatory activities. Diffusion studies showed that thrombus presence in AAAs is not a barrier to endovascular treatment. Together, these results provide a deeper understanding of the clinical potential of PGG as a non-surgical treatment of AAAs. [ABSTRACT FROM AUTHOR]

Marine compounds constitute a diverse and invaluable resource for the discovery of bioactive substances with promising applications in the pharmaceutical development of anti-inflammatory and antibacterial agents. In this study, a comprehensive methodology was employed, encompassing pharmacophore modeling, virtual screening, in silico ADMET assessment (encompassing aspects of absorption, distribution, metabolism, excretion, and toxicity), and molecular dynamics simulations. These methods were applied to identify new inhibitors targeting the Hsp90 protein (heat shock protein 90), commencing with a diverse assembly of compounds sourced from marine origins. During the virtual screening phase, an extensive exploration was conducted on a dataset comprising 31,488 compounds sourced from the CMNPD database, characterized by a wide array of molecular structures. The principal objective was the development of structure-based pharmacophore models, a valuable approach when the pool of known ligands is limited. The pharmacophore model DDRRR was successfully constructed within the active sites of the Hsp90 crystal structure. Subsequent docking studies led to the identification of six compounds (CMNPD 22591, 9335, 10015, 360799, 15115, and 20988) demonstrating substantial binding affinities, each with values below −8.3 kcal/mol. In the realm of in silico ADMET predictions, five of these compounds exhibited favorable pharmacokinetic properties. Furthermore, molecular dynamics simulations and total binding energy calculations using MM-PBSA indicated that these marine-derived compounds formed exceptionally stable complexes with the Hsp90 receptor over a 100-nanosecond simulation period. These findings underscore the considerable potential of these novel marine compounds as promising candidates for anticancer and antimicrobial drug development.

In this work we synthesized new monofunctional gold(III) complex [Au(Cl‐Ph‐tpy)Cl]Cl2 (Cl‐Ph‐tpy = 4′‐[4‐chlorophenyl]‐2,2′:6′, 2″‐terpyridine). This complex was characterized by UV–Vis, NMR, IR, and ESI‐MS spectrometry. The kinetic study of the substitution reactions of the Au‐Cl‐Ph‐tpy complex with biomolecules showed that the rate constants depend on the nature of the entering nucleophile. Based on the calculated values of entropy (∆H≠ > 0) and enthalpy (∆S≠ < 0) the proposed substitution mechanism is associative. Additionally, the relative stability and thermodynamic properties of Au‐Cl‐Ph‐tpy complex were compared with the analogue Au‐tpy complex by the B3LYP/def2‐svp method. DNA/BSA binding studies showed that Au‐Cl‐Ph‐tpy complex interacts with CT DNA through the intercalation and moderately quenches the fluorescence of tryptophan residues in serum albumin (BSA). Molecular docking confirmed results obtained by spectroscopic experiments and suggested site I (subdomain IIA) for binding of Au complex to BSA. We demonstrated that the Au chlorophenyl terpyridine complex possessed significant in vitro cytotoxic activity against human oral squamous carcinoma cells (CAL‐27), induced apoptosis, inhibited proliferation of CAL‐27 cells, and induced cell cycle disturbance. Treatment of CAL‐27 cells with the Au complex enhanced expression of cyclin‐dependent kinase inhibitors p21 and p27, resulting in cell cycle arrest in the G1 phase, reduced the percentage of CAL‐27 cells in S phase and decreased expression of Ki‐67. Additionally, Au complex reduced expression of phosphorylated STAT3 and downstream regulated molecules associated with cancer stemness, NANOG, and Sox2 protein. [ABSTRACT FROM AUTHOR]

In this study, the stereoisomers of two tetracyclic quinolines previously discovered as Pregnane X Receptor ligands were stereodiscriminated with a Chiralcel OD‐H column under normal‐phase conditions. The two compounds are characterized by a C/D cis ring junction and the co‐existence of four diastereoisomers for the presence of a further chiral center at the ring C. A mobile phase made‐up of n‐hexane/2‐PrOH – 99:1 (v/v) allowed to obtain the four peaks of each stereoisomer fully resolved with enantioseparation and enantioresolution factor values up to 2.98 and 11.16, respectively. Due to the lack of pure enantiomeric standards of known stereochemistry, an indirect protocol was successfully applied to define the enantiomeric elution order (EEO) under the identified optimal eluent conditions. This was possible by comparing experimental and theoretical Time‐Dependent Density Functional Theory (TD‐DFT) electronic circular dichroism spectra. In order to confirm the EEOs established through the ab initio calculations, molecular docking simulations were successfully performed with a nonameric model structure of the chiral selector. The results from the docking simulations were in perfect accordance with the results from the TD‐DFT study, thereby confirming the importance of performing multiple methods in the case of indirect attribution of the absolute configuration. [ABSTRACT FROM AUTHOR]

Pentagalloyl glucose (PGG) is currently being investigated as a non-surgical treatment for abdominal aortic aneurysms (AAAs); however, the molecular mechanisms of action of PGG on the AAA matrix components and the intra-luminal thrombus (ILT) still need to be better understood. To assess these interactions, we utilized peptide fingerprinting and molecular docking simulations to predict the binding of PGG to vascular proteins in normal and aneurysmal aorta, including matrix metalloproteinases (MMPs), cytokines, and fibrin. We performed PGG diffusion studies in pure fibrin gels and human ILT samples. PGG was predicted to bind with high affinity to most vascular proteins, the active sites of MMPs, and several cytokines known to be present in AAAs. Finally, despite potential binding to fibrin, PGG was shown to diffuse readily through thrombus at physiologic pressures. In conclusion, PGG can bind to all the normal and aneurysmal aorta protein components with high affinity, potentially protecting the tissue from degradation and exerting anti-inflammatory activities. Diffusion studies showed that thrombus presence in AAAs is not a barrier to endovascular treatment. Together, these results provide a deeper understanding of the clinical potential of PGG as a non-surgical treatment of AAAs.

Background: Tissue plasminogen activator (tPA) is one of the most widely used drugs in thrombolytic therapy. However, due to the inactivation of tPA in the bloodstream and increased risk of bleeding with increasing tPA dosages, the development of targeted delivery systems of tPA is required. For these purposes, it is possible to use fucoidan. The aim of the work was to study the possibility of forming of tPA-fucoidan conjugates and maintaining the activity of the enzyme using molecular docking. Methods: Docking simulations between tPA and fucoidan were performed by use of a docking software AutoDock tools version 1.5.7 and AutoDock 4.2.6. Using “blind docking” to identify the centers of molecular docking approaches of the enzyme (tPA) with the ligand (the active part of the fucoidan structure), as well as to establish the influence of the ligand on the active site of the enzyme. Results: Two “hot spots” of fucoidan binding to the enzyme were found: the region containing SER85-CYS97 residues and the region containing PHE217-TYR223 residues. This interaction can lead to the successful binding of the enzyme and polysaccharide to form a protein-polysaccharide complex. In this case, there may be a lack of suppression of the action of tPA. The interaction with the ligand was found to occur on the surface of the protein molecule. Conclusions: In this study, coupling simulations of interactions of tPA with fucoidan were conducted. The resulting conjugate can be used in the development of systems for the targeted delivery of a thrombolytic agent. This study predicts that the formation of tPA-fucoidan conjugate is a promising approach for optimizing treatment strategies for thrombosis.

The rapid and global propagation of the novel human coronavirus that causes severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has produced an immediate urgency to discover promising targets for the treatment of this virus. In this paper, we studied the spike protein S2 domain of SARS-CoV-2 as it is the most conserved component and controls the crucial fusion process of SARS-CoV-2 as a target for different databases of small organic compounds. Our in silico methodology, based on pharmacophore modeling, docking simulation and molecular dynamics simulations, was first validated with ADS-J1, a potent small-molecule HIV fusion inhibitor that has already proved effective in binding the HR1 domain and inhibiting the fusion core of SARS-CoV-1. It then focused on finding novel small molecules and new peptides as fusion inhibitors. Our methodology identified several small molecules and peptides as potential inhibitors of the fusion process. Among these, NF 023 hydrate (MolPort-006-822-583) is one of the best-scored compounds. Other compounds of interest are ZINC00097961973, Salvianolic acid, Thalassiolin A and marine_160925_88_2. Two interesting active peptides were also identified: AP00094 (Temporin A) and AVP1227 (GBVA5). The inhibition of the spike protein of SARS-CoV-2 is a valid target to inhibit the virus entry in human cells. The discussed compounds reported in this paper led to encouraging results for future in vitro tests against SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Background: Pulse crops are considered the major sources of proteins, dietary fiber, micronutrients, and bioactive phytochemicals. Among the numerous pulse crops, broad beans (Vicia faba L.) have received particular attention due to their nutraceutical, functional and economic importance. Our attention was mainly focused on the broad bean pods (VFs), which are the primary by-product of the domestic and industrial processing of broad beans and an attractive source of valuable ingredients. Methods: In order to investigate the VFs properties, the flours from broad beans of three different harvest periods were extracted with acetone, methanol and 70% aqueous ethanol and the dried extracts were analyzed, qualitatively and quantitatively, and tested for their antioxidant through DPPH and ABTS assay and anticancer activities using the MTT assay and immunofluorescence analysis. Results: The VF extracts demonstrated a good in vitro radical scavenging activity from the first stage of collection of all the V. faba L. extracts. Additionally, the extracts were tested for their cytotoxicity against a panel of cancer and normal cells and the outcomes indicated the ethanol extract as the most active against the melanoma cell line Sk-Mel-28, without affecting the viability of the normal cells. Finally, we found out that the ethanol extract interfered with the microtubules organization, leading to the cancer cells death by apoptosis. [ABSTRACT FROM AUTHOR]

Sesquiterpenes such as leucodin and the labdane-type diterpene manool are natural compounds endowed with remarkably in vitro vasorelaxant and in vivo hypotensive activities. Given their structural similarity with the sesquiterpene lactone (+)-sclareolide, this molecule was selected as a scaffold to develop novel vasoactive agents. Functional, electrophysiology, and molecular dynamics studies were performed. The opening of the five-member lactone ring in the (+)-sclareolide provided a series of labdane-based small molecules, promoting a significant in vitro vasorelaxant effect. Electrophysiology data identified 7 as a CaV1.2 channel blocker and a KCa1.1 channel stimulator. These activities were also confirmed in the intact vascular tissue. The significant antagonism caused by the CaV1.2 channel agonist Bay K 8644 suggested that 7 might interact with the dihydropyridine binding site. Docking and molecular dynamic simulations provided the molecular basis of the CaV1.2 channel blockade and KCa1.1 channel stimulation produced by 7. Finally, 7 reduced coronary perfusion pressure and heart rate, while prolonging conduction and refractoriness of the atrioventricular node, likely because of its Ca2+ antagonism. Taken together, these data indicate that the labdane scaffold represents a valuable starting point for the development of new vasorelaxant agents endowed with negative chronotropic properties and targeting key pathways involved in the pathophysiology of hypertension and ischemic cardiomyopathy. [ABSTRACT FROM AUTHOR]

Background Pulse crops are considered the major sources of proteins, dietary fiber, micronutrients, and bioactive phytochemicals. Among the numerous pulse crops, broad beans (Vicia faba L.) have received particular attention due to their nutraceutical, functional and economic importance. Our attention was mainly focused on the broad bean pods (VFs), which are the primary by-product of the domestic and industrial processing of broad beans and an attractive source of valuable ingredients. Methods In order to investigate the VFs properties, the flours from broad beans of three different harvest periods were extracted with acetone, methanol and 70% aqueous ethanol and the dried extracts were analyzed, qualitatively and quantitatively, and tested for their antioxidant through DPPH and ABTS assay and anticancer activities using the MTT assay and immunofluorescence analysis. Results The VF extracts demonstrated a good in vitro radical scavenging activity from the first stage of collection of all the V. faba L. extracts. Additionally, the extracts were tested for their cytotoxicity against a panel of cancer and normal cells and the outcomes indicated the ethanol extract as the most active against the melanoma cell line Sk-Mel-28, without affecting the viability of the normal cells. Finally, we found out that the ethanol extract interfered with the microtubules organization, leading to the cancer cells death by apoptosis.

(1) Background: carbonic anhydrases (CAs) are attractive targets for the development of new anticancer therapies; in particular, CAs IX and XII isoforms are overexpressed in numerous tumors. (2) Methods: following the tail approach, we have appended a hydrophobic aromatic tail to a pharmacophore responsible for the CA inhibition (aryl sulfonamide, coumarin). As a linker, we have used squaramides, featured with strong hydrogen bond acceptor and donor capacities. (3) Results: Starting from easily accessible dimethyl squarate, the title compounds were successfully obtained as crystalline solids, avoiding the use of chromatographic purifications. Interesting and valuable SARs could be obtained upon modification of the length of the hydrocarbon chain, position of the sulfonamido moiety, distance of the aryl sulfonamide scaffold to the squaramide, stereoelectronic effects on the aromatic ring, as well as the number and type of substituents on C-3 and C-4 positions of the coumarin. (4) Conclusions: For sulfonamides, the best profile was achieved for the m-substituted derivative 11 (Ki = 29.4, 9.15 nM, CA IX and XII, respectively), with improved selectivity compared to acetazolamide, a standard drug. Coumarin derivatives afforded an outstanding selectivity (Ki > 10,000 nM for CA I, II); the lead compound (16c) was a strong CA IX and XII inhibitor (Ki = 19.2, 7.23 nM, respectively). Docking simulations revealed the key ligand-enzyme interactions. [ABSTRACT FROM AUTHOR]

Background: Tissue plasminogen activator (tPA) is one of the most widely used drugs in thrombolytic therapy. However, due to the inactivation of tPA in the bloodstream and increased risk of bleeding with increasing tPA dosages, the development of targeted delivery systems of tPA is required. For these purposes, it is possible to use fucoidan. The aim of the work was to study the possibility of forming of tPA-fucoidan conjugates and maintaining the activity of the enzyme using molecular docking. Methods: Docking simulations between tPA and fucoidan were performed by use of a docking software AutoDock tools version 1.5.7 and AutoDock 4.2.6. Using "blind docking" to identify the centers of molecular docking approaches of the enzyme (tPA) with the ligand (the active part of the fucoidan structure), as well as to establish the influence of the ligand on the active site of the enzyme. Results: Two "hot spots" of fucoidan binding to the enzyme were found: the region containing SER85-CYS97 residues and the region containing PHE217-TYR223 residues. This interaction can lead to the successful binding of the enzyme and polysaccharide to form a protein-polysaccharide complex. In this case, there may be a lack of suppression of the action of tPA. The interaction with the ligand was found to occur on the surface of the protein molecule. Conclusions: In this study, coupling simulations of interactions of tPA with fucoidan were conducted. The resulting conjugate can be used in the development of systems for the targeted delivery of a thrombolytic agent. This study predicts that the formation of tPA-fucoidan conjugate is a promising approach for optimizing treatment strategies for thrombosis. [ABSTRACT FROM AUTHOR]

An attractive drug target to combat COVID‐19 is the main protease (Mpro) because of its key role in the viral life cycle by processing the polyproteins translated from the viral RNA. Studying the crystal structures of the protease is important to enhance our understanding of its mechanism of action at the atomic‐level resolution, and consequently may provide crucial structural insights for structure‐based drug discovery. In the current study, we report a comparative structural analysis of the Mpro substrate binding site for both apo and holo forms to identify key interacting residues and conserved water molecules during the ligand‐binding process. It is shown that in addition to the catalytic dyad residues (His41 and Cys145), the oxyanion hole residues (Asn142–Ser144) and residues His164–Glu166 form essential parts of the substrate‐binding pocket of the protease in the binding process. Furthermore, we address the issue of the substrate‐binding pocket flexibility and show that two adjacent loops in the Mpro structures (residues Thr45–Met49 and Arg188–Ala191) with high flexibility can regulate the binding cavity' accessibility for different ligand sizes. Moreover, we discuss in detail the various structural and functional roles of several important conserved and mobile water molecules within and around the binding site in the proper enzymatic function of Mpro. We also present a new docking protocol in the framework of the ensemble docking strategy. The performance of the docking protocol has been evaluated in predicting ligand binding pose and affinity ranking for two popular docking programs; AutoDock4 and AutoDock Vina. Our docking results suggest that the top‐ranked poses of the most populated clusters obtained by AutoDock Vina are the most important representative docking runs that show a very good performance in estimating experimental binding poses and affinity ranking. [ABSTRACT FROM AUTHOR]

2,4,5-Triaryl-1H-imidazole hybrids were synthesized from substituted benzil and indole-3-aldehyde which on subsequent treatment with aryl azides converted to 1,2,3-triazoles by employing click chemistry. All the synthesized hybrids were characterized by FTIR, 1H-NMR, 13C-NMR spectroscopy and HRMS. These scaffolds were tested in vitro for their antifungal evaluation against different candida species. Screening against the used fungal strains, the results outcome that imidazole-indole hybrids bearing antifungals more effectively reduced than imidazole-indole-1,2,3-triazole hybrids with their MIC80 values in the range of 2–128 µg/mL. Among all the synthesized hybrids, 2a and 2b were found to be the most potent against fungal strains as a result of different methods like, time kill assays, effect on fungal membrane and antibiofilm activity. The docking simulations of the most active hybrids, 2a, 2b and 2c were carried out in the active site of sterol 14-alpha demethylase enzyme of Candida albicans. [ABSTRACT FROM AUTHOR]

Human serum albumin (HSA) has a very significant role in the transport of drugs, in their pharmacokinetic and pharmacodynamic properties, as well as the unbound concentration of drugs in circulating plasma. The aim of this study was to look into the competition between tigecycline (TGC) and alkaloid (ALK) (caffeine (CAF)), and flavonoids (FLAVs) (catechin (CAT), quercetin (QUE), and diosmin (DIO)) in binding to HSA in simulated physiological conditions using multiple spectroscopic measurements and docking simulations. Fluorescence analysis was used to find the binding and quenching properties of double HSA-TGC and triple HSA-TGC-CAF/FLAV systems. The conformational change of the HSA was analyzed using synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism. Obtained results of spectroscopic analyses indicate that triple complexes of HSA-TGC-CAF/FLAVs are formed without problems and have higher binding affinities than double HSA-TGC. In addition, TGC does not change the microenvironments around the tryptophan (Trp) and tyrosine (Tyr) residues in the presence of ALK and FLAVs. Ultimately, the binding affinity, competition, and interaction nature were explored by docking modeling. Computational outcomes are in good accordance with experimentally obtained results. Accordingly, concluding remarks may be very useful for potential interactions between common food components and drugs. [ABSTRACT FROM AUTHOR]

We have designed unprecedented cholinesterase inhibitors based on 1-deoxynojirimycin as potential anti-Alzheimer’s agents. Compounds are comprised of three key structural motifs: the iminosugar, for interaction with cholinesterase catalytic anionic site (CAS); a hydrocarbon tether with variable lengths, and a fragment derived from 2-phenylethanol for promoting interactions with peripheral anionic site (PAS). Title compounds exhibited good selectivity towards BuChE, strongly depending on the substitution pattern and the length of the tether. The lead compounds were found to be strong mixed inhibitors of BuChE (IC50 = 1.8 and 1.9 µM). The presumptive binding mode of the lead compound was analysed using molecular docking simulations, revealing H-bond interactions with the catalytic subsite (His438) and CAS (Trp82 and Glu197) and van der Waals interactions with PAS (Thr284, Pro285, Asn289). They also lacked significant antiproliferative activity against tumour and non-tumour cells at 100 µM, making them promising new agents for tackling Alzheimer’s disease through the cholinergic approach.

The hydrogen/deuterium exchange (HDX) is a reliable method to survey the dynamic behavior of proteins and epitope mapping. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) is a quantifying tool to assay for HDX in the protein of interest. We combined HDX-MALDI-TOF MS and molecular docking/MD simulation to identify accessible amino acids and analyze their contribution into the structural changes of profilin-1 (PFN-1). The molecular docking/MD simulations are computational tools for enabling the analysis of the type of amino acids that may be involved via HDX identified under the lowest binding energy condition. Glycine to valine amino acid (G117V) substitution mutation is linked to amyotrophic lateral sclerosis (ALS). This mutation is found to be in the actin-binding site of PFN-1 and prevents the dimerization/polymerization of actin and invokes a pathologic toxicity that leads to ALS. In this study, we sought to understand the PFN-1 protein dynamic behavior using purified wild type and mutant PFN-1 proteins. The data obtained from HDX-MALDI-TOF MS for PFN-1WT and PFN-1G117V at various time intervals, from seconds to hours, revealed multiple peaks corresponding to molecular weights from monomers to multimers. PFN-1/Benzaldehyde complexes identified 20 accessible amino acids to HDX that participate in the docking simulation in the surface of WT and mutant PFN-1. Consistent results from HDX-MALDI-TOF MS and docking simulation predict candidate amino acid(s) involved in the dimerization/polymerization of PFNG117V. This information may shed critical light on the structural and conformational changes with details of amino acid epitopes for mutant PFN-1s' dimerization, oligomerization, and aggregation. [ABSTRACT FROM AUTHOR]

We have designed unprecedented cholinesterase inhibitors based on 1-deoxynojirimycin as potential anti-Alzheimer's agents. Compounds are comprised of three key structural motifs: the iminosugar, for interaction with cholinesterase catalytic anionic site (CAS); a hydrocarbon tether with variable lengths, and a fragment derived from 2-phenylethanol for promoting interactions with peripheral anionic site (PAS). Title compounds exhibited good selectivity towards BuChE, strongly depending on the substitution pattern and the length of the tether. The lead compounds were found to be strong mixed inhibitors of BuChE (IC50 = 1.8 and 1.9 µM). The presumptive binding mode of the lead compound was analysed using molecular docking simulations, revealing H-bond interactions with the catalytic subsite (His438) and CAS (Trp82 and Glu197) and van der Waals interactions with PAS (Thr284, Pro285, Asn289). They also lacked significant antiproliferative activity against tumour and non-tumour cells at 100 µM, making them promising new agents for tackling Alzheimer's disease through the cholinergic approach. [ABSTRACT FROM AUTHOR]

Breast cancer is still considered a high-incidence disease, and numerous are the research efforts for the development of new useful and effective therapies. Among anticancer drugs, carbazole compounds are largely studied for their anticancer properties and their ability to interfere with specific targets, such as microtubule components. The latter are involved in vital cellular functions, and the perturbation of their dynamics leads to cell cycle arrest and subsequent apoptosis. In this context, we report the anticancer activity of a series of carbazole analogues 1–8. Among them, 2-nitrocarbazole 1 exhibited the best cytotoxic profile, showing good anticancer activity against two breast cancer cell lines, namely MCF-7 and MDA-MB-231, with IC50 values of 7 ± 1.0 and 11.6 ± 0.8 μM, respectively. Furthermore, compound 1 did not interfere with the growth of the normal cell line MCF-10A, contrarily to Ellipticine, a well-known carbazole derivative used as a reference molecule. Finally, in vitro immunofluorescence analysis and in silico studies allowed us to demonstrate the ability of compound 1 to interfere with tubulin organization, similarly to vinblastine: a feature that results in triggering MCF-7 cell death by apoptosis, as demonstrated using a TUNEL assay. [ABSTRACT FROM AUTHOR]

The interaction between human serum transferrin (hTf) and three promising organometallic Ru (II)- (η5-C5H5) derived complexes, that have already shown strong in vitro cytotoxicity towards human cancer cell lines, has been investigated using fluorescence spectroscopic techniques. The results suggested that the formation of Ru-hTf systems involves a dynamic collision. The binding process occurs spontaneously (ΔG < 0), mainly driven by hydrophobic interactions. Additional docking studies show that all complexes bind preferably to a specific hydrophobic pocket in the C2-subdomain as already observed for other metal-cyclopentadienyl (MCp) complexes and are in agreement with the experimental results. With these studies we hope to contribute to the understanding of the mechanism of action of these promising cytotoxic agents, thus providing clues for a more rational design. [ABSTRACT FROM AUTHOR]

The rapid and global propagation of the novel human coronavirus that causes severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has produced an immediate urgency to discover promising targets for the treatment of this virus. In this paper, we studied the spike protein S2 domain of SARS-CoV-2 as it is the most conserved component and controls the crucial fusion process of SARS-CoV-2 as a target for different databases of small organic compounds. Our in silico methodology, based on pharmacophore modeling, docking simulation and molecular dynamics simulations, was first validated with ADS-J1, a potent small-molecule HIV fusion inhibitor that has already proved effective in binding the HR1 domain and inhibiting the fusion core of SARS-CoV-1. It then focused on finding novel small molecules and new peptides as fusion inhibitors. Our methodology identified several small molecules and peptides as potential inhibitors of the fusion process. Among these, NF 023 hydrate (MolPort-006-822-583) is one of the best-scored compounds. Other compounds of interest are ZINC00097961973, Salvianolic acid, Thalassiolin A and marine_160925_88_2. Two interesting active peptides were also identified: AP00094 (Temporin A) and AVP1227 (GBVA5). The inhibition of the spike protein of SARS-CoV-2 is a valid target to inhibit the virus entry in human cells. The discussed compounds reported in this paper led to encouraging results for future in vitro tests against SARS-CoV-2.

(1) Background: carbonic anhydrases (CAs) are attractive targets for the development of new anticancer therapies; in particular, CAs IX and XII isoforms are overexpressed in numerous tumors. (2) Methods: following the tail approach, we have appended a hydrophobic aromatic tail to a pharmacophore responsible for the CA inhibition (aryl sulfonamide, coumarin). As a linker, we have used squaramides, featured with strong hydrogen bond acceptor and donor capacities. (3) Results: Starting from easily accessible dimethyl squarate, the title compounds were successfully obtained as crystalline solids, avoiding the use of chromatographic purifications. Interesting and valuable SARs could be obtained upon modification of the length of the hydrocarbon chain, position of the sulfonamido moiety, distance of the aryl sulfonamide scaffold to the squaramide, stereoelectronic effects on the aromatic ring, as well as the number and type of substituents on C-3 and C-4 positions of the coumarin. (4) Conclusions: For sulfonamides, the best profile was achieved for the m-substituted derivative 11 (Ki = 29.4, 9.15 nM, CA IX and XII, respectively), with improved selectivity compared to acetazolamide, a standard drug. Coumarin derivatives afforded an outstanding selectivity (Ki > 10,000 nM for CA I, II); the lead compound (16c) was a strong CA IX and XII inhibitor (Ki = 19.2, 7.23 nM, respectively). Docking simulations revealed the key ligand-enzyme interactions.

The recently emerged COVID-19 virus caused hundreds of thousands of deaths and instigated a widespread fear, threatening the world’s most advanced health security. In 2020, chloroquine derivatives are among the drugs tested against the coronavirus pandemic and showed an apparent efficacy. In the present work, the chloroquine and the chloroquine phosphate molecules have been proposed as potential antiviral for the treatment of COVID-19 diseases combining DFT and molecular docking calculations. Molecular geometries, electronic properties and molecular electrostatic potential were investigated using density functional theory (DFT) at the B3LYP/6-31G* method. As results, we found a good agreement between the theoretical and the experimental geometrical parameters (bond lengths and bond angles). The frontier orbitals analysis has been calculated at the same level of theory to determine the charge transfer within the molecule. In order to perform a better description of the FMOs, the density of states was determined. The molecular electrostatic potential maps were calculated to provide information on the chemical reactivity of molecule and also to describe the intermolecular interactions. All these studies help us a lot in determining the reactivity of the mentioned compounds. Finally, docking calculations were carried out to determine the pharmaceutical activities of the chloroquine derivatives against coronavirus diseases. The choice of these ligands was based on their antiviral activities.

Human serum albumin (HSA) has a very significant role in the transport of drugs, in their pharmacokinetic and pharmacodynamic properties, as well as the unbound concentration of drugs in circulating plasma. The aim of this study was to look into the competition between tigecycline (TGC) and alkaloid (ALK) (caffeine (CAF)), and flavonoids (FLAVs) (catechin (CAT), quercetin (QUE), and diosmin (DIO)) in binding to HSA in simulated physiological conditions using multiple spectroscopic measurements and docking simulations. Fluorescence analysis was used to find the binding and quenching properties of double HSA-TGC and triple HSA-TGC-CAF/FLAV systems. The conformational change of the HSA was analyzed using synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism. Obtained results of spectroscopic analyses indicate that triple complexes of HSA-TGC-CAF/FLAVs are formed without problems and have higher binding affinities than double HSA-TGC. In addition, TGC does not change the microenvironments around the tryptophan (Trp) and tyrosine (Tyr) residues in the presence of ALK and FLAVs. Ultimately, the binding affinity, competition, and interaction nature were explored by docking modeling. Computational outcomes are in good accordance with experimentally obtained results. Accordingly, concluding remarks may be very useful for potential interactions between common food components and drugs.

Objectives: To develop of new class of selective and reversible MAO‐B inhibitors from enamides. Methods: Syntheses of the titled derivatives (AD1–AD11) were achieved by reacting cinnamoyl chloride and various primary and secondary amines in basic medium. All eleven compounds were investigated for in vitro inhibitory activities against recombinant human MAO‐A and MAO‐B. The reversibilities of lead compound inhibitions were analysed by dialysis. MTT assays of lead compounds were performed using normal VERO cell lines. Key findings: Compounds AD3 and AD9 exhibited the greatest inhibitory activity against MAO‐B with IC50 values of 0.11 and 0.10 µm, respectively, and were followed by AD2 and AD1 (0.51 and 0.71 µm, respectively). Most of the compounds weakly inhibited MAO‐A, with the exceptions AD9 and AD7, which had IC50 values of 4.21 and 5.95 µm, respectively. AD3 had the highest selectivity index (SI) value for MAO‐B (>363.6) and was followed by AD9 (SI 42.1). AD3 and AD9 were found to be competitive inhibitors of MAO‐B with Ki values of 0.044 ± 0.0036 and 0.039 ± 0.0047 µm, respectively. Reversibility experiments showed AD3 and AD9 were reversible inhibitors of MAO‐B; dialysis restored the activity of MAO‐B to the reference level. MTT assays revealed AD3 and AD9 were non‐toxic to normal VERO cell lines with IC50 values of 153.96 and 194.04 µg/ml, respectively. Computational studies provided hypothetical binding modes for AD3 and AD9 in the binding cavities of MAO‐A and MAO‐B. Conclusions: These results encourage further studies on the enamide scaffold as potential drug candidates for the treatment of Alzheimer's and Parkinson's diseases. [ABSTRACT FROM AUTHOR]

Carboxypeptidase A (CPA) (EC 3.4.17.1) is one of the main members of the M14 family that release one amino acid from the C-terminal region of the polypeptides at each time. The purpose of the present study was to study the effect of spermidine (NH 2 (CH 2) 3 NH (CH 2) 4 NH 2) on the conformation, thermal stability, and activity of native CPA from bovine pancreas, by employing ultraviolet–visible (UV–Vis) spectroscopy, intrinsic fluorescence, thermal stability, circular dichroism (CD), kinetic techniques and molecular docking. It was found that the decrease in the CPA, UV–Vis absorption could be due to the formation of the CPA–spermidine complexes. The results of fluorescence spectroscopic measurements at the temperatures of 308 and 318 K also revealed that spermidine had the capability to quench the intrinsic fluorescence of CPA with the static mode. Further, the thermodynamic parameters, (Gibbs free-energy, enthalpy and entropy changes) showed that the binding process of spermidine to CPA was spontaneous and the main force in stabilizing the complex was the van der Waals and hydrogen interactions, along with the molecular docking results. In addition, CD spectra and fluorescence results revealed that spermidine had a partial effect on the CPA structure, leading to some changes in its secondary structure. The T m studies of the CPA–spermidine complex also indicated that the T m values were enhanced with increasing the spermidine concentration. Kinetic studies further showed that by spermidine binding, the V max value and activity of the enzyme were increased. [ABSTRACT FROM AUTHOR]

OXER1, the receptor for the oxidized arachidonic acid metabolite 5-oxo-ETE has been reported to play a significant role in inflammatory responses, being responsible for leucocyte chemotactic responses. Recently, we have identified OXER1 (GPR170) as a membrane receptor for androgens in prostate and breast cancer cells. Testosterone action via OXER1 induces specific Ca2+ release from intracellular organelles, modifies polymerized actin distribution induces apoptosis and decreases cancer cell migration. These actions are antagonized by 5-oxo-ETE. In addition, 5-oxo-ETE through a G αi protein decreases cAMP, an action antagonized by testosterone. In this work, we mined the ZINC15 database, using QSAR, for natural compounds able to signal through G αi and G βγ simultaneously, mimicking testosterone actions, as well as for specific G βγ interactors, inhibiting 5-oxo-ETE tumor promoting actions. We were able to identify four druggable G αβγ and seven G βγ specific OXER1 interactors. We further confirmed by bio-informatic methods their binding to the 5-oxo-ETE/testosterone binding groove of the receptor, their ADME properties and their possible interaction with other receptor and/or enzyme targets. Two compounds, ZINC04017374 (Naphthofluorescein) and ZINC08589130 (Puertogaline A) were purchased, tested in vitro and confirmed their OXER1 G βγ and G αβγ activity, respectively. The methodology followed is useful for a better understanding of the mechanism by which OXER1 mediates its actions, it has the potential to provide structural insights, in order to design small molecular specific interactors and ultimately design new anti-inflammatory and anti-cancer agents. Finally, the methodology may also be useful for identifying specific agonists/antagonists of other GPCRs. [ABSTRACT FROM AUTHOR]

Breast cancer is still considered a high-incidence disease, and numerous are the research efforts for the development of new useful and effective therapies. Among anticancer drugs, carbazole compounds are largely studied for their anticancer properties and their ability to interfere with specific targets, such as microtubule components. The latter are involved in vital cellular functions, and the perturbation of their dynamics leads to cell cycle arrest and subsequent apoptosis. In this context, we report the anticancer activity of a series of carbazole analogues 1–8. Among them, 2-nitrocarbazole 1 exhibited the best cytotoxic profile, showing good anticancer activity against two breast cancer cell lines, namely MCF-7 and MDA-MB-231, with IC50 values of 7 ± 1.0 and 11.6 ± 0.8 μM, respectively. Furthermore, compound 1 did not interfere with the growth of the normal cell line MCF-10A, contrarily to Ellipticine, a well-known carbazole derivative used as a reference molecule. Finally, in vitro immunofluorescence analysis and in silico studies allowed us to demonstrate the ability of compound 1 to interfere with tubulin organization, similarly to vinblastine: a feature that results in triggering MCF-7 cell death by apoptosis, as demonstrated using a TUNEL assay.

A series of sixteen 1-(4-arylthiazol-2-yl)-1′-(aryl/heteroaryl)-3,3′-dimethyl-[ 4,5′-bi-1H-pyrazol]-5-ols (7a–p) was synthesized starting from dehydroacetic acid (DHA, 1) via the stepwise formation of thiosemicarbazone (2), 3-(1-(2-(4-arylthiazol-2-yl)hydrazono)ethyl)-4-hydroxy-6-methyl-2H-pyran- -2-ones (4a–d) and 1-(1-(4-arylthiazol-2-yl)-5-hydroxy-3-methyl-1H-pyrazol- -4-yl)butane-1,3-diones (5a–d) in high yields. The in vitro antibacterial and antifungal activities of the synthesized bipyrazoles 7a–p were investigated against two Gram-positive bacterial strains, viz. Bacillus subtilis (MTCC 441) and Staphylococcus aureus (MTCC 7443), one Gram-negative bacterial strain, viz. Escherichia coli (MTCC 42), and two fungal strains, viz. Candida albicans (MTCC 183) and Aspergillus niger (MTCC 282). The compounds 7a and 7e were found to exhibit better inhibitory activity against A. niger than the reference fluconazole. Moreover, the antifungal activities of the title compounds were more prolific than their antibacterial activities. Furthermore, in order to study binding interactions, docking simulations of compounds 7a, 7m and 7o were performed into the active site of S. aureus 1,4-dihydroxy-2-naphthoyl- -CoA synthase. Keywords: bipyrazoles; antibacterial; antifungal; docking simulations.

Bufotalin (BFT), one of the naturally occurring bufodienolides, has multiple pharmacological and toxicological effects including antitumor activity and cardiotoxicity. This study aimed to character the metabolic pathway(s) of BFT and to identify the key drug metabolizing enzyme(s) responsible for hepatic metabolism of BFT in human, as well as to explore the related molecular mechanism of enzymatic selectivity. The major metabolite of BFT in human liver microsomes (HLMs) was fully identified as 5β-hydroxylbufotalin by LC-MS/MS and NMR techniques. Reaction phenotyping and chemical inhibition assays showed that CYP3A4 and CYP3A5 were key enzymes responsible for BFT 5β-hydroxylation. Kinetic analyses demonstrated that BFT 5β-hydroxylation in both HLMs and human CYP3A4 followed the biphasic kinetics, while BFT 5β-hydroxylation in CYP3A5 followed substrate inhibition kinetics. Furthermore, molecular docking simulations showed that BFT could bind on two different ligand-binding sites on both CYP3A4 and CYP3A5, which partially explained the different kinetic behaviors of BFT in CYP3A4 and CYP3A5. These findings are very helpful for elucidating the phase I metabolism of BFT in human and for deeper understanding the key interactions between CYP3A enzymes and bufadienolides, as well as for the development of bufadienolide-type drugs with improved pharmacokinetic and safety profiles.