A theoretical protocol for the rational design of the bioinspired multifunctional hybrid material MIP@cercosporin.

CONTEXT: Rational design of polymeric materials prepared with the molecular imprinting technology is gaining even more space, as it can provide the optimal conditions to direct the laboratory molecularly imprinting polymer (MIP) preparation, maximizing their efficiency while reducing costs and preparation time, when compared to try-and-error approaches. We perform a rational design of an MIP with specific cavities for cercosporin accommodation by means of computational tools. The main steps of an MIP preparation were simulated and it was found that the most appropriated functional monomer to be used in the MIP preparation for cercosporin is the acrylamide, while the most suitable crosslinking agent is found to be p-divinylbenzene. Also, the most suitable solvents to remove cercosporin from the cavity are those with low dielectric constant, such as chloroform. This kind of solvent can then be used in washing step, in the case of use the MIP for sensing destinations. On the other hand, solvents like water, which has high dielectric constants, can efficiently improve the interactions between cercosporin and the functional monomer acrylamide, being indicated when the objective is to attract or maintain the cercosporin inside the MIP cavity. Thus, a MIP@cercosporin hybrid material can be used in aqueous solutions more reliably, or even the cercosporin detection in this media can be favoured. In the selectivity analysis of the material prepared in this specific condition, the results point that this MIP can also detect elsinochrome A with high efficiency, and could be more selective for hypericin, altertoxin, hypocrelin A, and phleichrome mycotoxins. METHOD: The main steps of a MIP synthesis were theoretically simulated trough density functional theory (DFT) calculations aiming to direct and optimize the synthesis and applications of the material before the bench tests. Initially, in order to choose the most suitable functional to be employed for cercosporin calculations, eight of the DFT functionals that had been previously used for cercosporin calculations in literature were tested, which were the LCWPBE, B3LYP, CAM-B3LYP, M062-X, mPW1PW91, PBE0, TPSSh, and ωb97Xd. The theoretical 1H NMR chemical shifts for cercosporin molecule were calculated and compared with experimental results to analyze the performance of the functionals. Of all these, the best results were obtained with the TPSSh functional, employing the 6-31G(d,p) basis set, and this level of theory was then used for all the following steps. All the simulations were performed by means of geometry optimizations and frequency calculations. Additionally, AIM calculations were employed for further analysis of the interactions between the chosen functional monomer and cercosporin template in step 1, which was functional monomer selection. In washing step, the calculations were done using implicit solvation model, and finally, in selectivity tests, the putative "solid" MIP was simulated by freezing the positions of the monomers after the template remotion, and then other structurally similar toxins were placed in its cavity for the geometry optimizations and frequency calculations.

Vanillic acid as phospholipase A2 and proteases inhibitor: In vitro and computational analyses.

Enzymatic inhibition by natural compounds may represent a valuable adjuvant in snakebite serum therapy. The objective in this work was to evaluate possible in vitro interactions between vanillic acid and enzymes from Bothrops spp. and Crotalus durissus terrificus venoms, and also suggest a theory as how they interact based on molecular docking. Vanillic acid inhibited the phospholipase activity induced by Bothrops alternatus (∼25% inhibition); the caseinolytic activity induced by Bothrops atrox (∼30%), Bothrops jararacussu (∼44%), and C. d. terrificus (∼33%); the fibrinogenolysis induced by B. jararacussu, B. atrox, and C. d. terrificus (100%); the serine protease activity induced by Bothrops moojeni (∼45%) and Bothrops jararaca (∼66%); the hemolytic activity induced by B. moojeni (∼26%); the thrombolysis activity induced by B. atrox (∼30%) and B. jararacussu (∼20%); and the thrombotic activity induced by C. d. terrificus (∼8%). The compound was also capable of delaying the coagulation time in citrated plasma by 60, 35, and 75 Sec, when incubated with B. moojeni, B. atrox, and B. jararaca, respectively. The results obtained expand the possibilities for future pharmaceutical use of vanillic acid, considering the high homology degree among human and snake venom phospholipases A2 and proteases (involved in chronic inflammatory diseases). Also, this compound can be used as adjuvant to improve currently available treatments for ophidism victims.

Current Anti-Inflammatory Therapies and the Potential of Secretory Phospholipase A2 Inhibitors in the Design of New Anti-Inflammatory Drugs: A Review of 2012 - 2018.

The inflammatory process is a natural self-defense response of the organism to damage agents and its action mechanism involves a series of complex reactions. However, in some cases, this process can become chronic, causing much harm to the body. Therefore, over the years, many anti-inflammatory drugs have been developed aiming to decrease the concentrations of inflammatory mediators in the organism, which is a way of controlling these abnormal chain reactions. The main target of conventional anti-inflammatory drugs is the cyclooxygenase (COX) enzyme, but its use implies several side effects. Thus, based on these limitations, many studies have been performed, aiming to create new drugs, with new action mechanisms. In this sense, the phospholipase A2 (PLA2) enzymes stand out. Among all the existing isoforms, secretory PLA2 is the major target for inhibitor development, since many studies have proven that this enzyme participates in various inflammatory conditions, such as cancer, Alzheimer and arthritis. Finally, for the purpose of developing anti-inflammatory drugs that are sPLA2 inhibitors, many molecules have been designed. Accordingly, this work presents an overview of inflammatory processes and mediators, the current available anti-inflammatory drugs, and it briefly covers the PLA2 enzymes, as well as the diverse structural array of the newest sPLA2 inhibitors as a possible target for the production of new anti-inflammatory drugs.

Molecular interactions between p-coumaric acid and snake venom toxins.

A large number of natural compounds, such as phenolic compounds, have been scientifically evaluated in the search for enzyme inhibitors. The interactions between the phenolic compound p-coumaric acid and the enzymes present in snake venoms (used as research tools) were evaluated in vitro and in silico. The p-coumaric acid was able to inhibit 31% of the phospholipase activity induced by Bothrops alternatus venom, 27% of the hemolytic activity induced by B. moojeni, 62.5% of the thrombolytic activity induced by B. jararacussu, and approximately 27% of the activity thrombosis induced by Crotalus durissus terrificus. Previous incubation of p-coumaric acid with the venoms of B. atrox and B. jararacussu increased the coagulation time by 2.18 and 2.16-fold, respectively. The activity of serine proteases in B. atrox and B. jararacussu venoms was reduced by 60% and 66.34%, respectively. Computational chemistry analyses suggests the specific binding of p-coumaric acid to the active site of proteases through hydrogen and hydrophobic interactions. The phenolic compound evaluated in this work has great potential in therapeutic use to both prevent and treat hemostatic alterations, because the venom proteins inhibited by the p-coumaric acid have high homology with human proteins that have a fundamental role in several pathologies.

Recent Developments in Metal-Based Drugs and Chelating Agents for Neurodegenerative Diseases Treatments.

The brain has a unique biological complexity and is responsible for important functions in the human body, such as the command of cognitive and motor functions. Disruptive disorders that affect this organ, e.g. neurodegenerative diseases (NDDs), can lead to permanent damage, impairing the patients' quality of life and even causing death. In spite of their clinical diversity, these NDDs share common characteristics, such as the accumulation of specific proteins in the cells, the compromise of the metal ion homeostasis in the brain, among others. Despite considerable advances in understanding the mechanisms of these diseases and advances in the development of treatments, these disorders remain uncured. Considering the diversity of mechanisms that act in NDDs, a wide range of compounds have been developed to act by different means. Thus, promising compounds with contrasting properties, such as chelating agents and metal-based drugs have been proposed to act on different molecular targets as well as to contribute to the same goal, which is the treatment of NDDs. This review seeks to discuss the different roles and recent developments of metal-based drugs, such as metal complexes and metal chelating agents as a proposal for the treatment of NDDs.

Can Inhibitors of Snake Venom Phospholipases A2 Lead to New Insights into Anti-Inflammatory Therapy in Humans? A Theoretical Study.

Human phospholipase A2 (hPLA2) of the IIA group (HGIIA) catalyzes the hydrolysis of membrane phospholipids, producing arachidonic acid and originating potent inflammatory mediators. Therefore, molecules that can inhibit this enzyme are a source of potential anti-inflammatory drugs, with different action mechanisms of known anti-inflammatory agents. For the study and development of new anti-inflammatory drugs with this action mechanism, snake venom PLA2 (svPLA2) can be employed, since the svPLA2 has high similarity with the human PLA2 HGIIA. Despite the high similarity between these secretory PLA2s, it is still not clear if these toxins can really be employed as an experimental model to predict the interactions that occur with the human PLA2 HGIIA and its inhibitors. Thus, the present study aims to compare and evaluate, by means of theoretical calculations, docking and molecular dynamics simulations, as well as experimental studies, the interactions of human PLA2 HGIIA and two svPLA2s,Bothrops toxin II and Crotoxin B (BthTX-II and CB, respectively). Our theoretical findings corroborate experimental data and point out that the human PLA2 HGIIA and svPLA2 BthTX-II lead to similar interactions with the studied compounds. From our results, the svPLA2 BthTX-II can be used as an experimental model for the development of anti-inflammatory drugs for therapy in humans.