In silico approaches to develop new phenyl-pyrimidines as glycogen synthase kinase 3 (GSK-3) inhibitors with halogen-bonding capabilities: 3D-QSAR CoMFA/CoMSIA, molecular docking and molecular dynamics studies

Glycogen synthase kinase 3 (GSK-3) is involved in different diseases, such as manic-depressive illness, Alzheimer's disease and cancer. Studies have shown that insulin inhibits GSK-3 to keep glycogen synthase active. Inhibiting GSK-3 may have an indirect pro-insulin effect by favouring glycogen synthesis. Therefore, the development of GSK-3 inhibitors can be a useful alternative for the treatment of type II diabetes. Aminopyrimidine derivatives already proved to be interesting GSK-3 inhibitors. In the current study, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) have been performed on a series of 122 aminopyrimidine derivatives in order to generate a robust model for the rational design of new compounds with promising antidiabetic activity. The q2 values obtained for the best CoMFA and CoMSIA models have been 0.563 and 0.598, respectively. In addition, the r2 values have been 0.823 and 0.925 for CoMFA and CoMSIA, respectively. The models were statistically validated, and from the contour maps analysis, a proposal of 10 new compounds has been generated, with predicted pIC50 higher than 9. The final contribution of our work is that: (a) we provide an extensive structure-activity relationship for GSK-3 inhibitory pyrimidines; and (b) these models may speed up the discovery of GSK-3 inhibitors based on the aminopyrimidine scaffold. Finally, we carried out docking and molecular dynamics studies of the two best candidates, which were shown to establish halogen-bond interactions with the enzyme.Communicated by Ramaswamy H. Sarma.

Single Mutation on Trastuzumab Modulates the Stability of Antibody-Drug Conjugates Built Using Acetal-Based Linkers and Thiol-Maleimide Chemistry

Antibody-drug conjugates (ADCs) are a class of targeted therapeutics used to selectively kill cancer cells. It is important that they remain intact in the bloodstream and release their payload in the target cancer cell for maximum efficacy and minimum toxicity. The development of effective ADCs requires the study of factors that can alter the stability of these therapeutics at the atomic level. Here, we present a general strategy that combines synthesis, bioconjugation, linker technology, site-directed mutagenesis, and modeling to investigate the influence of the site and microenvironment of the trastuzumab antibody on the stability of the conjugation and linkers. Trastuzumab is widely used to produce targeted ADCs because it can target with high specificity a receptor that is overexpressed in certain breast cancer cells (HER2). We show that the chemical environment of the conjugation site of trastuzumab plays a key role in the stability of linkers featuring acid-sensitive groups such as acetals. More specifically, Lys-207, located near the reactive Cys-205 of a thiomab variant of the antibody, may act as an acid catalyst and promote the hydrolysis of acetals. Mutation of Lys-207 into an alanine or using a longer linker that separates this residue from the acetal group stabilizes the conjugates. Analogously, Lys-207 promotes the beneficial hydrolysis of the succinimide ring when maleimide reagents are used for conjugation, thus stabilizing the subsequent ADCs by impairing the undesired retro-Michael reactions. This work provides new insights for the design of novel ADCs with improved stability properties.

3-Phenylcoumarins as a Privileged Scaffold in Medicinal Chemistry: The Landmarks of the Past Decade

3-Phenylcoumarins are a family of heterocyclic molecules that are widely used in both organic and medicinal chemistry. In this overview, research on this scaffold, since 2010, is included and discussed, focusing on aspects related to its natural origin, synthetic procedures and pharmacological applications. This review paper is based on the most relevant literature related to the role of 3-phenylcoumarins in the design of new drug candidates. The references presented in this review have been collected from multiple electronic databases, including SciFinder, Pubmed and Mendeley.

Computer-Aided Design of Coumarins for Neurodegenerative diseases: Trends of the Last Decade

Computer-aided design of new drugs is an exponentially growing field, especially in the last decade. The support of theoretical tools may accelerate the drug discovery process, which is a long and very expensive journey. Tools as QSAR and docking calculations are on the top of the list for helping medicinal chemists to find more potent and selective molecules as potential leads for facing challenging diseases. Coumarins have been an important source of inspiration for the design of new drugs. Due to their chemical properties and their affinity to some targets, special attention has been paid to their role against neurodegenerative diseases. Therefore, the authors provide an overview of the scientific reports describing the research and development of new drug design tools supporting the discovery of coumarins as enzymatic inhibitors or receptor ligands involved in these diseases. This review emphasizes the rationale behind the design of new drug candidates, and particular attention is paid to the search for new leads over the last 10 years. QSAR and docking studies are discussed, as well as new technologies applied for the research in this field. The manuscripts discussed in this review have been collected from multiple electronic databases, including Pubmed, SciFinder, and Mendeley.

Combined 3D-QSAR and docking analysis for the design and synthesis of chalcones as potent and selective monoamine oxidase B inhibitors

Monoamine oxidases (MAOs) are important targets in medicinal chemistry, as their inhibition may change the levels of different neurotransmitters in the brain, and also the production of oxidative stress species. New chemical entities able to interact selectively with one of the MAO isoforms are being extensively studied, and chalcones proved to be promising molecules. In the current work, we focused our attention on the understanding of theoretical models that may predict the MAO-B activity and selectivity of new chalcones. 3D-QSAR models, in particular CoMFA and CoMSIA, and docking simulations analysis have been carried out, and their successful implementation was corroborated by studying twenty-three synthetized chalcones (151-173) based on the generated information. All the synthetized molecules proved to inhibit MAO-B, being ten out of them MAO-B potent and selective inhibitors, with IC₅₀ against this isoform in the nanomolar range, being (E)-3-(4-hydroxyphenyl)-1-(2,2-dimethylchroman-6-yl)prop-2-en-1-one (152) the best MAO-B inhibitor (IC₅₀ of 170 nM). Docking simulations on both MAO-A and MAO-B binding pockets, using compound 152, were carried out. Calculated affinity energy for the MAO-A was +2.3 Kcal/mol, and for the MAO-B was -10.3 Kcal/mol, justifying the MAO-B high selectivity of these compounds. Both theoretical and experimental structure-activity relationship studies were performed, and substitution patterns were established to increase MAO-B selectivity and inhibitory efficacy. Therefore, we proved that both 3D-QSAR models and molecular docking approaches enhance the probability of finding new potent and selective MAO-B inhibitors, avoiding time-consuming and costly synthesis and biological evaluations.

Sequential dual site-selective protein labelling enabled by lysine modification

Methods that allow for chemical site-selective dual protein modification are scarce. Here, we provide proof-of-concept for the orthogonality and compatibility of a method for regioselective lysine modification with strategies for protein modification at cysteine and genetically encoded ketone-tagged amino acids. This sequential, orthogonal approach was applied to albumin and a therapeutic antibody to create functional dual site-selectively labelled proteins.

7-Amidocoumarins as Multitarget Agents against Neurodegenerative Diseases: Substitution Pattern Modulation

This study explores the potential of 7-amidocoumarins as multitarget agents against Parkinson's and Alzheimer's diseases, by modulating the substitution patterns within the scaffold. Sixteen compounds were synthesized via 7-amino-4-methylcoumarin acylation, and in vitro evaluation of the molecules against hMAO-A, hMAO-B, hAChE, hBuChE and hBACE1 was performed. Five compounds turned out to be potent and selective hMAO-B inhibitors in the nanomolar range, six displayed inhibitory activity of hMAO-A in the low micromolar range, one showed hAChE inhibitory activity and another one hBACE1 inhibitory activity. MAO-B reversibility profile of 7-(4'-chlorobenzamido)-4-methylcoumarin (10) was investigated, with this compound being a reversible inhibitor. Neurotoxicity on motor cortex neurons and neuroprotection against H₂ O₂ were also studied, corroborating the safety profile of these molecules. Finally, theoretical ADME properties were also calculated, showing these molecules as good candidates for the optimization of a lead compound. Results suggest that by modulating the substitution pattern at position 7 of the scaffold, selective or multitarget molecules can be achieved.

Coumarin-Rasagiline Hybrids as Potent and Selective hMAO-B Inhibitors, Antioxidants, and Neuroprotective Agents

The frequency, complexity and morbidity of neurodegenerative diseases make them a great challenge for nowadays medicine. Most of the treatments currently used for Parkinson's disease - the second most prevalent - are only symptomatic. Therefore, it is urgent to develop drugs that are able to act simultaneously on different targets, being able to stop neuronal death and promote the recovery of neuronal populations already affected. In this work, we studied the activity of a series of hybrid molecules, which combine the structure of both coumarin and an alkynylamine group inspired on rasagiline, as MAO inhibitors, antioxidants and neuroprotective agents. Half of the studied hybrids turned out to be selective monoamine oxidase B (hMAO-B) inhibitors in the low micro/nanomolar range, demonstrating that positions 3 (compounds 1-3) and 7 (compounds 8 and 10) of the coumarin scaffold are the most suitable for the incorporation of the alkynylamine chain. All the studied compounds proved to be capable of neutralizing free radicals (DPPH). Finally, the 4-(but-2-yn-1-ylamino)coumarin (5) showed neuroprotective effects on glial cells and the 4-methyl-7-(pent-2-yn-1-ylamino)coumarin (8) inhibited intraneuronal ROS production as well.

Artificial Intelligence Applied to Flavonoid Data in Food Matrices

Increasing interest in constituents and dietary supplements has created the need for more efficient use of this information in nutrition-related fields. The present work aims to obtain optimal models to predict the total antioxidant properties of food matrices, using available information on the amount and class of flavonoids present in vegetables. A new dataset using databases that collect the flavonoid content of selected foods has been created. Structural information was obtained using a structural-topological approach called TOPological Sub-Structural Molecular (TOPSMODE). Different artificial intelligence algorithms were applied, including Machine Learning (ML) methods. The study allowed us to demonstrate the effectiveness of the models using structural-topological characteristics of dietary flavonoids. The proposed models can be considered, without overfitting, effective in predicting new values of Oxygen Radical Absorption capacity (ORAC), except in the Multi-Layer Perceptron (MLP) algorithm. The best optimal model was obtained by the Random Forest (RF) algorithm. The in silico methodology we developed allows us to confirm the effectiveness of the obtained models, by introducing the new structural-topological attributes, as well as selecting those that most influence the class variable.

Enhancement of the Anti-Aggregation Activity of a Molecular Chaperone Using a Rationally Designed Post-Translational Modification

Protein behavior is closely regulated by a plethora of post-translational modifications (PTMs). It is therefore desirable to develop approaches to design rational PTMs to modulate specific protein functions. Here, we report one such method, and we illustrate its successful implementation by potentiating the anti-aggregation activity of a molecular chaperone. Molecular chaperones are a multifaceted class of proteins essential to protein homeostasis, and one of their major functions is to combat protein misfolding and aggregation, a phenomenon linked to a number of human disorders. In this work, we conjugated a small-molecule inhibitor of the aggregation of α-synuclein, a process associated with Parkinson's disease (PD), to a specific cysteine residue on human Hsp70, a molecular chaperone with five free cysteines. We show that this regioselective conjugation augments in vitro the anti-aggregation activity of Hsp70 in a synergistic manner. This Hsp70 variant also displays in vivo an enhanced suppression of α-synuclein aggregation and its associated toxicity in a Caenorhabditis elegans model of PD.

Quaternization of Vinyl/Alkynyl Pyridine Enables Ultrafast Cysteine-Selective Protein Modification and Charge Modulation

Quaternized vinyl‐ and alkynyl‐pyridine reagents were shown to react in an ultrafast and selective manner with several cysteine‐tagged proteins at near‐stoichiometric quantities. We have demonstrated that this method can effectively create a homogenous antibody–drug conjugate that features a precise drug‐to‐antibody ratio of 2, which was stable in human plasma and retained its specificity towards Her2+ cells. Finally, the developed warhead introduces a +1 charge to the overall net charge of the protein, which enabled us to show that the electrophoretic mobility of the protein may be tuned through the simple attachment of a quaternized vinyl pyridinium reagent at the cysteine residues. We anticipate the generalized use of quaternized vinyl‐ and alkynyl‐pyridine reagents not only for bioconjugation, but also as warheads for covalent inhibition and as tools to profile cysteine reactivity.

Lysine Bioconjugation on Native Albumin with a Sulfonyl Acrylate Reagent

This protocol details a novel bioconjugation strategy that uses a methanesulfonyl acrylate reagent that is directed to the most reactive lysine on human serum albumin, which enables the construction of chemically defined and stable bioconjugates. The reaction proceeds rapidly and a regioselective modification is achieved using a single molar equivalent of the reagent under biocompatible conditions (37 °C, pH 8.0). Importantly, the bioconjugate retains both the secondary structural content and function of the unmodified protein. During the reaction of the amino group of lysine and the sulfonyl acrylate reagent, methanesulfinic acid is released after the conjugate addition, which then generates an electrophilic acrylate moiety on the protein. This acrylate can be further used for site-specific protein labeling using a synthetic molecule bearing a reactive amine under biocompatible conditions (21 °C, pH 8.0).

Synthesis and Biological Evaluation of Homogeneous Thiol-Linked NHC*-Au-Albumin and -Trastuzumab Bioconjugates

Targeted delivery of potent cytotoxic drugs to cancer cells minimizes systemic toxicity and several side effects. NHC*-Au-Cl has already been proven to be a potent anticancer agent. In this study, we explore a strategy based on chemoselective cysteine conjugation of NHC*-Au-Cl to albumin and trastuzumab (Thiomab LC-V205C) to potentiate drug-ligand ratio, pharmacokinetics, as well as drug efficacy and safety. This strategy is a step forward towards the use of gold-based anticancer agents as targeted therapies.

A thioether-directed palladium-cleavable linker for targeted bioorthogonal drug decaging

We describe the development of a bifunctional linker that simultaneously allows site-specific protein modification and palladium-mediated bioorthogonal decaging.

We describe the development of a bifunctional linker that simultaneously allows site-specific protein modification and palladium-mediated bioorthogonal decaging. This was enabled by a thioether binding motif in the propargyl carbamate linker and a readily available palladium complex. We demonstrate the efficiency of this reaction by controlled drug release from a PEGylated doxorubicin prodrug in cancer cells. The linker can be easily installed into cysteine bearing proteins which we demonstrated for the construction of an anti-HER2 nanobody–drug conjugate. Targeted delivery of the nanobody drug conjugate showed effective cell killing in HER2+ cells upon palladium-mediated decaging.

Chemo- and Regioselective Lysine Modification on Native Proteins

Site-selective chemical conjugation of synthetic molecules to proteins expands their functional and therapeutic capacity. Current protein modification methods, based on synthetic and biochemical technologies, can achieve site selectivity, but these techniques often require extensive sequence engineering or are restricted to the N- or C-terminus. Here we show the computer-assisted design of sulfonyl acrylate reagents for the modification of a single lysine residue on native protein sequences. This feature of the designed sulfonyl acrylates, together with the innate and subtle reactivity differences conferred by the unique local microenvironment surrounding each lysine, contribute to the observed regioselectivity of the reaction. Moreover, this site selectivity was predicted computationally, where the lysine with the lowest pK_a was the kinetically favored residue at slightly basic pH. Chemoselectivity was also observed as the reagent reacted preferentially at lysine, even in those cases when other nucleophilic residues such as cysteine were present. The reaction is fast and proceeds using a single molar equivalent of the sulfonyl acrylate reagent under biocompatible conditions (37 °C, pH 8.0). This technology was demonstrated by the quantitative and irreversible modification of five different proteins including the clinically used therapeutic antibody Trastuzumab without prior sequence engineering. Importantly, their native secondary structure and functionality is retained after the modification. This regioselective lysine modification method allows for further bioconjugation through aza-Michael addition to the acrylate electrophile that is generated by spontaneous elimination of methanesulfinic acid upon lysine labeling. We showed that a protein–antibody conjugate bearing a site-specifically installed fluorophore at lysine could be used for selective imaging of apoptotic cells and detection of Her2+ cells, respectively. This simple, robust method does not require genetic engineering and may be generally used for accessing diverse, well-defined protein conjugates for basic biology and therapeutic studies.

Chemoselective Installation of Amine Bonds on Proteins through Aza-Michael Ligation

Chemical modification of proteins is essential for a variety of important diagnostic and therapeutic applications. Many strategies developed to date lack chemo- and regioselectivity as well as result in non-native linkages that may suffer from instability in vivo and adversely affect the protein's structure and function. We describe here the reaction of N-nucleophiles with the amino acid dehydroalanine (Dha) in a protein context. When Dha is chemically installed in proteins, the addition of a wide-range N-nucleophiles enables the rapid formation of amine linkages (secondary and tertiary) in a chemoselective manner under mild, biocompatible conditions. These new linkages are stable at a wide range of pH values (pH 2.8 to 12.8), under reducing conditions (biological thiols such as glutathione) and in human plasma. This method is demonstrated for three proteins and is shown to be fully compatible with disulfide bridges, as evidenced by the selective modification of recombinant albumin that displays 17 structurally relevant disulfides. The practicability and utility of our approach is further demonstrated by the construction of a chemically modified C2A domain of Synaptotagmin-I protein that retains its ability to preferentially bind to apoptotic cells at a level comparable to the native protein. Importantly, the method was useful for building a homogeneous antibody-drug conjugate with a precise drug-to-antibody ratio of 2. The kinase inhibitor crizotinib was directly conjugated to Dha through its piperidine motif, and its antibody-mediated intracellular delivery results in 10-fold improvement of its cancer cell-killing efficacy. The simplicity and exquisite site-selectivity of the aza-Michael ligation described herein allows the construction of stable secondary and tertiary amine-linked protein conjugates without affecting the structure and function of biologically relevant proteins.

MAO inhibitory activity of bromo-2-phenylbenzofurans: synthesis, in vitro study, and docking calculations

Monoamine oxidase (MAO) is an enzyme responsible for metabolism of monoamine neurotransmitters which play an important role in brain development and function. This enzyme exists in two isoforms, and it has been demonstrated that MAO-B activity, but not MAO-A activity, increases with aging. MAO inhibitors show clinical value because besides the monoamine level regulation they reduce the formation of by-products of the MAO catalytic cycle, which are toxic to the brain. A series of 2-phenylbenzofuran derivatives was designed, synthesized and evaluated against hMAO-A and hMAO-B enzymes. A bromine substituent was introduced in the 2-phenyl ring, whereas position 5 or 7 of the benzofuran moiety was substituted with a methyl group. Most of the tested compounds inhibited preferentially MAO-B in a reversible manner, with IC50 values in the low micro or nanomolar range. The 2-(2'-bromophenyl)-5-methylbenzofuran (5) was the most active compound identified (IC50 = 0.20 μM). In addition, none of the studied compounds showed cytotoxic activity against the human neuroblastoma cell line SH-SY5Y. Molecular docking simulations were used to explain the observed hMAO-B structure-activity relationship for this type of compounds.

In silico genotoxicity of coumarins: application of the Phenol-Explorer food database to functional food science

Coumarins are a group of phytochemicals that may be beneficial or harmful to health depending on their type and dosage and the matrix that contains them. Some of these compounds have been proven to display pro-oxidant and clastogenic activities. Therefore, in the current work, we have studied the coumarins that are present in food sources extracted from the Phenol-Explorer database in order to predict their clastogenic activity and identify the structure-activity relationships and genotoxic structural alerts using alternative methods in the field of computational toxicology. It was necessary to compile information on the type and amount of coumarins in different food sources through the analysis of databases of food composition available online. A virtual screening using a clastogenic model and different software, such as MODESLAB, ChemDraw and STATISTIC, was performed. As a result, a table of food composition was prepared and qualitative information from this data was extracted. The virtual screening showed that the esterified substituents inactivate molecules, while the methoxyl and hydroxyl substituents contribute to their activity and constitute, together with the basic structures of the studied subclasses, clastogenic structural alerts. Chemical subclasses of simple coumarins and furocoumarins were classified as active (xanthotoxin, isopimpinellin, esculin, scopoletin, scopolin and bergapten). In silico genotoxicity was mainly predicted for coumarins found in beer, sherry, dried parsley, fresh parsley and raw celery stalks. The results obtained can be interesting for the future design of functional foods and dietary supplements. These studies constitute a reference for the genotoxic chemoinformatic analysis of bioactive compounds present in databases of food composition.

Trends in therapeutic drug conjugates for bacterial diseases: a patent review

INTRODUCTION

Drug conjugates are trend topics in Chemical Biology. These entities are an emerging class of highly potent biopharmaceutical drugs, best known in the field of oncology, that have been also designed as a targeted therapy/diagnosis for the treatment/prevention of several bacterial diseases. Antibiotic resistance is now a major threat to public health, and targeted strategies can reduce resistance. The following review aims at giving an overview of the patented therapeutic innovations covering these areas. Particular attention has been given to antibacterial drug conjugates in the last 30 years. Areas covered: The authors provide an overview of the scientific reports describing the research and development of new drug conjugates for bacterial diseases. The review emphasizes the rationale behind synthesis, biological activities and improvement of the new drug conjugates. New technologies applied for the research in this field have also been discussed. The article is based on the most relevant literature related to the development of new therapeutic solutions. The patents presented in this review have been collected from multiple electronic databases including SciFinder, Pubmed, Espacenet and Mendeley. Expert opinion: The new drug conjugates described in the current review proved to display improved delivery, efficacy, targeting abilities and fewer side effects. Versatile approaches were invented to achieve these goals.

Overlap syndrome--Asthma and obstructive sleep apnea

INTRODUCTION

Asthma is a chronic inflammatory disease with multiple phenotypes. There is still a major gap in the understanding of its complex causality. Obstructive sleep apnea (OSA) is a common condition that has been implicated as a risk factor for asthma exacerbations.

OBJECTIVES

This study aims to characterize patients with the diagnosis of asthma and suspected OSA; identify the presence of OSA and review, on the current literature, the association between asthma and OSA, as an overlap syndrome.

MATERIALS AND METHODS

The authors present a retrospective study that included patients diagnosed with asthma that underwent sleep study in a 3 year period. Demographic, clinical data, body mass index (BMI), sleep study parameters and treatments were analyzed.

RESULTS

The sample consisted of 47 patients. The majority of population was females (68%) and the mean age was 55.65 ± 13.04 years. The most common nighttime symptom was snoring (93.6%). Regarding BMI, values above the normal limit were observed in 89.36% of the patients. 68% underwent polysomnography and the others cardiorespiratory polygraphy. In 57.4% of the patients, OSA was confirmed with a higher prevalence in males (73.3%) compared to females (50%). The therapeutic approach in 81.8% of these patients was home ventilation therapy.

CONCLUSION

The combination of asthma and OSA has become increasingly more frequent. In the described study, the prevalence of OSA was 57.4%, value that is in fact higher than in general population. After the therapeutic approach, all patients referred improvement of symptoms. It is therefore essential that OSA is investigated in patients with asthma when there is poor control of symptoms, in order to achieve a better control.

Adult bronchiolitis--a clinical and pathological interpretative classification

INTRODUCTION

Bronchiolitis is a heterogeneous group of diseases of an inflammatory nature, centered on small conducting airways and often associated with other pulmonary disorders. No single classification scheme for bronchiolar diseases has been widely accepted. In this retrospective study, it was decided to apply a new clinical and pathological interpretative classification.

OBJECTIVES

To propose a new clinical and pathological interpretative classification for adult bronchiolitis, based on statistical analysis of a population of 193 patients with histopathological diagnosis of bronchiolitis.

MATERIALS AND METHODS

A retrospective study analyzed the epidemiological characteristics, co-morbidities and radiological findings present in a group of patients with histopathological diagnosis of bronchiolitis.

RESULTS

This trial involved 193 cases collected over a period of eleven years; 48 (24.9%) patients had simultaneous pulmonary disease; non-pulmonary diseases, such as cardiovascular diseases, type II Diabetes mellitus and dyslipidemia were present in 57 cases. The image study was extremely important in order to integrate clinical and pathological aspects. In this study respiratory bronchiolitis related to smoking dominated. The radiological findings confirmed the secondary nature of the histopathological features, with prevalence of ground-glass patterns, pneumothorax and patterns of interstitial involvement, as described in the literature. It was also verified that clinical behavior of different forms of bronchiolitis was important to distinguish the various types, since they could progress without typical anatomopathological aspects.

CONCLUSION

This trial showed that the vast majority of diagnosis obtained corresponded to bronchiolitis as secondary to pulmonary pathology. In most cases, morphological findings had to be complemented with clinical and radiological characteristics, in order to obtain the final diagnosis.

Development of novel adenosine receptor ligands based on the 3-amidocoumarin scaffold

With the aim of finding new adenosine receptor (AR) ligands presenting the 3-amidocoumarin scaffold, a study focusing on the discovery of new chemical entities was carried out. The synthesized compounds 1-8 were evaluated in radioligand binding (A1, A2A and A3) and adenylyl cyclase activity (A2B) assays in order to determine their affinity for human AR subtypes. The 3-benzamide derivative 4 showed the highest affinity of the whole series and was more than 30-fold selective for the A3 AR (Ki=3.24 μM). The current study supported that small structural changes in this scaffold allowed modulating the affinity resulting in novel promising classes of A1, A2A, and/or A3 AR ligands. We also performed docking calculations in hA2A and hA3 to identify the hypothetical binding mode for the most active compounds. In addition, some ADME properties were calculated in order to better understand the potential of these compounds as drug candidates.

Study of coumarin-resveratrol hybrids as potent antioxidant compounds

In the present work we synthesized a selected series of hydroxylated 3-phenylcoumarins 5–8, with the aim of evaluating in detail their antioxidant properties. From an in depth study of the antioxidant capacity data (ORAC-FL, ESR, CV and ROS inhibition) it was concluded that these derivatives are very good antioxidants, with very interesting profiles in all the performed assays. The study of the effect of the number and position of the hydroxyl groups on the antioxidant activity was the principal aim of this study. In particular, 7-hydroxy-3-(3'-hydroxy)phenylcoumarin (8) proved to be the most active and effective antioxidant of the selected series in four of the performed assays (ORAC-FL = 11.8, capacity of scavenging hydroxyl radicals = 54%, Trolox index = 2.33 and AI₃₀ index = 0.18). However, the presence of two hydroxyl groups on this molecule did not increase greatly the activity profile. Theoretical evaluation of ADME properties of all the derivatives was also carried out. All the compounds can act as potential candidates for preventing or minimizing the free radical overproduction in oxidative-stress related diseases. These preliminary findings encourage us to perform a future structural optimization of this family of compounds.

Alternative functional criteria to assess airflow-limitation reversibility in asthma

INTRODUCTION

International guidelines define significant bronchodilator response as absolute and percentage change from baseline in forced expiratory volume (FEV1) in the first second and/or forced vital capacity (FVC) ≥12% and 200 mL. However, bronchodilator effects on other lung function parameters have also been correlated to some degree of reversible airflow limitation.

OBJECTIVES

To determine whether changes in other lung function parameters apart from FEV1 and FVC detect functional responses to bronchodilator in asthmatic patients.

MATERIALS AND METHODS

Spirometry and body plethysmography were performed at baseline conditions and after administration of 400 μg of salbutamol by metered-dose inhaler through a space chamber device in asthmatic patients. Paired t-tests were used to compare lung function parameters between those with and without criteria for reversibility of airway obstruction according to ATS/ERS criteria. Cut-off values were obtained from the corresponding ROC curves. Measurements evaluated were FEV1, FVC, maximum mid-forced expiratory flow (FEF25-75%), residual volume (RV), inspiratory capacity (IC), airway resistance (Raw) and specific airway conductance (sGaw).

RESULTS

From a total of 100 consecutive asthmatics patients (46% of them men; average age 58.7±14.1 years; 76% with mild to moderate obstruction), 50 patients had a significant bronchodilator response. All of these had noteworthy variations (p<0.004) in PEF, FEF25-75%, RV, Raw and sGaw. The most accurate in predicting a significant bronchodilator response were the absolute and percentage improvements in PEF (≥0.4 L/s and 8%), FEF25-75% (≥0.087 L/s and 27%) and the percentage of sGaw compared with that at baseline (≥25%). Based on these cut-off values, a sizeable number of the patients defined as non-responders had important changes in airway caliber. 17 patients had significant increments in the percentage of PEF and 10 had changes in absolute volume; 6 patients had increments in percentage and 16 in absolute change of FEF25-75%; 22 patients had increments in the percentage change of sGaw.

CONCLUSIONS

Changes of FEV1 and/or FVC may underestimate significant functional response to bronchodilators in asthmatic patients with airway obstruction when considering the change in other lung function parameters.

WITHDRAWN: Alternative functional criteria to assess airflow-limitation reversibility in asthma

This article has been withdrawn for editorial reasons because the journal will be published only in English. In order to avoid duplicated records, this article can be found at http://dx.doi.org/10.1016/j.rppnen.2014.08.002. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

(1S,2S,5S)-2-Methyl-3-oxo-5-(prop-1-en-2-yl)cyclohexane-1-carbonitrile

The mol­ecule of the title compound, C₁₁H₁₅NO, contains a cyclo­hexa­none ring, three defined stereocenters and an exocyclic double bond. The crystal structure is the result of a study on the Michael addition reaction of (S)-carvone with sodium cyanide using ionic liquids as the reaction medium and so the absolute configuration is known from the chemistry. The six-membered ring is in a chair conformation.

[(2S,3aR,6aR)-5-Oxohexa-hydro-furo[3,2-b]furan-2-yl]methyl acetate

The title compound, C9H12O5, is a bicyclic lactone, presenting a 2,6-dioxabi-cyclo-[3.3.0]octan-3-one skeleton, which was obtained through an intra-molecular lactonization. The bicyclic lactone presents a cis ring-junction and a 1,5-trans-substituted tetra-hydro-furan. Both five-membered rings are in twisted envelope conformations with one of the fused C atoms as the flap. The dihedral angle between the mean planes of the bicyclic lactone residue, defined by the di-hydro-furan-2(3H)-one and the tetra-hydro-furan rings, is 69.5 (2)°. The atoms of the ester chain are coplanar [maximum deviation = 0.013 (2) Å]. The absolute structure was not determined.

Novel (coumarin-3-yl)carbamates as selective MAO-B inhibitors: synthesis, in vitro and in vivo assays, theoretical evaluation of ADME properties and docking study

A series of (coumarin-3-yl)carbamates was synthesized and evaluated in vitro as monoamine oxidase (MAO-A and MAO-B) inhibitors. Most of the new compounds selectively inhibited MAO-B isoenzyme with IC50 values in the micro or nanoMolar ranges. Since these compounds must achieve the brain cells, theoretical evaluation of ADME properties were also carried out. Compound 8 (benzyl(coumarin-3-yl)carbamate), which presented the most interesting in vitro MAO-B inhibitory profile (IC50 against MAO-B = 45 nM), was subjected to further studies. This in vitro MAO-B inhibitory activity is comparable with that of the selegiline, the reference compound (IC50 against MAO-B = 20 nM). Taking into account the in vitro results of compound 8, in vivo assays and docking calculations were also carried out for this derivative.

N-(2-Oxo-2H-chromen-3-yl)cyclo-hexane-carboxamide

In the title compound, C₁₆H₁₇NO₃, the coumarin moiety is essentially planar [maximum deviation from the mean plane formed by the C and O atoms of the coumarin = 0.0183 (12) Å] and that the cyclo­hexane ring adopts the usual chair conformation. The dihedral angle between the mean plane of the coumarin residue and the plane of the amide residue (defined as the N, C and O atoms) is 18.9 (2)°. There are two intra­molecular hydrogen bonds involving the amide group. In one, the N atom acts as donor to the ketonic O atom and in the other, the amide O atom acts as acceptor of a C—H group of the coumarin. In the crystal, mol­ecules are linked into inversion dimers by pairs of N—H⋯O contacts and these dimers are linked into pairs by weak C—H⋯O hydrogen bonds. The combination of these inter­actions creates a chain of rings which runs parallel to [2-10]. C—H⋯π and π–π [centroid–centroid distance = 3.8654 (10) Å] inter­actions are also observed.

Prevalence of obesity and its relationship to clinical lipodystrophy in HIV-infected adults on anti-retroviral therapy

BACKGROUND

Combination antiretroviral therapy (cART) is associated with lipodystrophy (lipoatrophy and lipoaccumulation) and several metabolic abnormalities that together can contribute to an increased cardiovascular risk. The aim of this study was to evaluate the prevalence of obesity in patients on cART according to the presence of clinical lipodystrophy (CL) and to analyze factors associated with obesity.

METHODS

We evaluated 368 HIV-infected adults on cART.

RESULTS

CL was present in 59.0%. Independently of gender, patients with CL were more frequently underweight [5.7% (21/368)] and of normal weight [47.3% (174/368)], and less frequently overweight [33.2% (122/368)] or obese [13.9% (51/368)]. Mean body mass index was higher in patients with abdominal prominence regardless of the presence of clinical lipoatrophy. Patients with CL had lower waist circumference, higher waist/hip and fat mass ratio and lower total and subcutaneous fat, without significant difference in visceral fat but with a higher visceral/subcutaneous fat ratio, as evaluated by CT at abdominal level. CL was significantly less frequent in overweight [odds ratio (OR)=0.21, 95% confidence interval (CI): 0.05-0.92] and obese (OR=0.05, 95%CI: 0.01-0.26) patients, when compared to underweight ones, independent of age, gender, duration of infection, cART regimen, virological suppression, and HIV-infection risk factor.

CONCLUSIONS

Being overweight or obese is highly prevalent in HIV-infected patients on cART. Patients with CL were more frequently under- or normal weight, and less frequently overweight or obese. Obesity is a condition that should be considered in HIV patients on cART.

3-Phenyl-coumarin

In the title compound, C(15)H(10)O(2), a 3-phenyl derivative of the coumarin (also known as 2H-chromen-2-one or 2H-1-benzopyran-2-one) scaffold, the C(p)-C(p)-C(c)-C(c) torsion angle between the coumarin (c) ring system and the phenyl (p) ring is -47.6 (2)°.

Synthesis and study of a series of 3-arylcoumarins as potent and selective monoamine oxidase B inhibitors

New series of 6-substituted-3-arylcoumarins displaying several alkyl, hydroxyl, halogen, and alkoxy groups in the two benzene rings have been designed, synthesized, and evaluated in vitro as human monoamine oxidase A and B (hMAO-A and hMAO-B) inhibitors. Most of the studied compounds showed a high affinity and selectivity to the hMAO-B isoenzyme, with IC(50) values on nanomolar and picomolar range. Ten of the 22 described compounds displayed higher MAO-B inhibitory activity and selectivity than selegiline. Coumarin 7 is the most active compound of this series, being 64 times more active than selegiline and also showing the highest hMAO-B specificity. In addition, docking experiments were carried out on hMAO-A and h-MAO-B structures. This study provided new information about the enzyme-inhibitor interaction and the potential therapeutic application of this 3-arylcoumarin scaffold.

Diagnosis of respiratory bronchiolitis associated interstitial lung disease

BACKGROUND

Respiratory Bronchiolitis (RB), described by Niewoehner et al in 1974, is a common finding in heavy smokers and is characterised by the presence of pigmented macrophages within respiratory bronchioles and adjacent alveoli. In the 1980s, Myers et al described RB associated with interstitial lung disease (RBILD), which is a rare entity expressed as an amplified respiratory bronchiolitis in response to cigarette smoke.

METHODS

The authors studied a group of 8 patients with biopsy-proven RBILD diagnosed within the last five years, and assessed epidemiological data, clinical and imaging features, lung function tests, bronchoalveolar lavage findings, therapeutic approaches and clinical evolution.

RESULTS AND CONCLUSIONS

The most difficult differential diagnosis is between RBILD and Desquamative Interstitial Pneumonia (DIP), which seems to suggest that these disorders are either end of the same spectrum, although the authors claim that there are some clinical, morphological and prognostic distinctions. The diagnosis of RBILD requires an appropriate clinical setting (including smoking habits), characteristic image findings (like ground glass shadowing and centrilobular nodules), and Bronchoalveolar Lavage (BAL) data to exclude other diagnosis. Pathological confirmation may also be important, not only to exclude more adverse interstitial lung disease, such as idiopathic pulmonary fibrosis, but also, as in the eight cases presented, to illustrate some specific features such as the prevalence of lymphocytosis in BAL.