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Author(s):  
Jéssica Santos Gomes ◽  
Érica Abadia Da Costa ◽  
Rodrigo A. A. Munoz ◽  
Alberto De Oliveira ◽  
Raquel M. F. Sousa

Abstract Most electrochemical sensors reported for catechin determination in herbal medicines actually involve the detection of not only catechins but also other flavonoids. This work proposes a strategy to selectively detect and quantify flavan-3-ol, known as catechins, in the presence of other flavonoids by complexation with AlCl3. Flavonoids (e.g.,rutin, quercetin) form stable complex with AlCl3 which affect the electrooxidation of these molecules. Hence, the electrochemical oxidation of catechin is free from the interference of other flavonoids as shown by differential-pulse voltammetry using glassy-carbon electrode. The approach was applied to herbal medicines and mass-spectrometry confirmed the presence of catechins in such samples.


2022 ◽  
Author(s):  
Elena Sapogova

The textbook contains systematized information about psychological, socio-cultural, historical-ethnographic, psychobiological and other aspects of the development of a person changing over time. The first section is devoted to general theoretical problems of developmental psychology, the second to the analysis of different ages. The comprehensive nature of the manual makes it possible to solve the problems of formation in the professional consciousness of a stable complex of scientific categories and concepts, with the help of which the factual diversity of manifestations of the mental life of a developing person is described in psychology; familiarization with classical and modern interpretations of human development, with different variants of psychological interpretation of its essence, nature, mechanisms, driving forces and contradictions; disclosure of dialectics and phenomenology of the formation of a person as a cultural and historical subject; formation of ideas about the complexity and ambiguity of the evolution of a child as a human being; understanding the basic laws of the formation of personality and individuality of a person at each stage of its development. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for the study of the discipline "Developmental psychology, age psychology" during the professional training of psychologists in universities and is aimed at students of bachelor's and master's degrees in psychology faculties of classical and pedagogical universities, humanities and medical universities, as well as graduate students, psychology teachers and practical psychologists who are improving their qualifications in the field of age psychology.


Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 465
Author(s):  
Pálma Bucur ◽  
Ibolya Fülöp ◽  
Emese Sipos

Around 5% of the population of the world is affected with the disease called diabetes mellitus. The main medication of the diabetes is the insulin; the active form is the insulin monomer, which is an instable molecule, because the long storage time, or the high temperature, can cause the monomer insulin to adapt an alternative fold, rich in β-sheets, which is pharmaceutically inactive. The aim of this study is to form different insulin complexes with all the cyclodextrin used for pharmaceutical excipients (native cyclodextrin, methyl, hydroxyethyl, hydroxypropyl and sulfobutylether substituted β-cyclodextrin), in silico condition, with the AutoDock molecular modeling program, to determine the best type of cyclodextrin or cyclodextrin derivate to form a complex with an insulin monomer, to predict the molar ratio, the conformation of the complex, and the intermolecular hydrogen bonds formed between the cyclodextrin and the insulin. From the results calculated by the AutoDock program it can be predicted that insulin can make a stable complex with 5–7 molecules of hydroxypropyl-β-cyclodextrin or sulfobutylether-β-cyclodextrin, and by forming a complex potentially can prevent or delay the amyloid fibrillation of the insulin and increase the stability of the molecule.


2022 ◽  
Vol 12 ◽  
Author(s):  
Nabarun Chandra Das ◽  
Pritha Chakraborty ◽  
Jagadeesh Bayry ◽  
Suprabhat Mukherjee

Since the start of the pandemic, SARS-CoV-2 has already infected more than 250 million people globally, with more than five million fatal cases and huge socio-economic losses. In addition to corticosteroids, and antiviral drugs like remdesivir, various immunotherapies including monoclonal antibodies (mAbs) to S protein of SARS-CoV-2 have been investigated to treat COVID-19 patients. These mAbs were initially developed against the wild-type SARS-CoV-2; however, emergence of variant forms of SARS-CoV-2 having mutations in the spike protein in several countries including India raised serious questions on the potential use of these mAbs against SARS-CoV-2 variants. In this study, using an in silico approach, we have examined the binding abilities of eight mAbs against several SARS-CoV-2 variants of Alpha (B.1.1.7) and Delta (B.1.617.2) lineages. The structure of the Fab region of each mAb was designed in silico and subjected to molecular docking against each mutant protein. mAbs were subjected to two levels of selection based on their binding energy, stability, and conformational flexibility. Our data reveal that tixagevimab, regdanvimab, and cilgavimab can efficiently neutralize most of the SARS-CoV-2 Alpha strains while tixagevimab, bamlanivimab, and sotrovimab can form a stable complex with the Delta variants. Based on these data, we have designed, by in silico, a chimeric antibody by conjugating the CDRH3 of regdanivimab with a sotrovimab framework to combat the variants that could potentially escape from the mAb-mediated neutralization. Our finding suggests that though currently available mAbs could be used to treat COVID-19 caused by the variants of SARS-CoV-2, better results could be expected with the chimeric antibodies.


2022 ◽  
Author(s):  
Colette Ashande ◽  
Adrien Masunda ◽  
Koto-te-Nyiwa Ngbolua ◽  
Jason Thambwe Kilembe ◽  
Aristote Matondo ◽  
...  

Diabetes mellitus is a major public health problem in the world. In Africa, more than 80% of patients use plants for their treatment. However, the methods of validation of endogenous knowledge usually used are costly. The alternative method developed in this study aims at creating hyperglycemia <i>in vitro</i> and exploiting the metabolic pathway involving glucose oxidase for UV-visible spectrophotometric screening of medicinal plants’ antidiabetic activity. The evolution of glucose oxidation as a function of drug concentration is followed by UV-visible spectrophotometry. The formation of the stable complex between the enzyme and the inhibitor is studied using molecular docking. Drugs used (Gliben) and plant extracts exhibited an <i>in vitro</i> hypoglycemic effect by reducing exponentially, <i>in vitro</i>, the level of free glucose. The results also showed that <i>L. multiflora</i> is more active than <i>V. amygdalina</i> (IC<sub>50</sub>: 1.36 ± 0.09 mg/mL Vs IC<sub>50</sub>: 3.00 ± 0.54 mg/mL). Gliben (0.5 mg/mL) and <i>L. multiflora</i> (2 mg/mL) reduced both the rate of oxidation of glucose by glucose oxidase (catalytic power V<sub>max</sub>: 0.84 ± 0.11 mg*mL<sup>-1</sup>*min<sup>-1</sup> for Gliben and 1.72 ± 0.13 mg*mL<sup>-1</sup>*min<sup>-1</sup> for <sup>L. multiflora</sup>); and the affinity of this enzyme for its substrate-glucose (K<sub>M</sub>: 15.11 ± 2.72 mg*mL<sup>-1</sup> for Gliben and 9.17 ± 1.56 mg*mL<sup>-1</sup> for <i>L. multiflora</i>) when these results are compared to enzyme catalysis in the absence of inhibitor (V<sub>max</sub>: 2.86 ± 0.44 mg*mL<sup>-1</sup>*min-1; K<sub>M</sub>: 8.07 ± 1.96 mg*mL<sup>-1</sup>). The binding of GOX (1GAL) to selected phytocompounds derived from <i>L. multiflora</i> was confirmed by molecular docking. The most stable complexes were obtained for four compounds; <b>8</b> (-10.1±0.0 Kcal/mol), <b>6</b> (-9.5±0.1 Kcal/mol), <b>3</b> (-8.3±0.0 Kcal/mol) and <b>9</b> (-8.2±0.1 Kcal/mol). Among these, compounds <b>8</b> and <b>6</b> formed complexes with the enzyme stabilized by hydrogen bonds, the compound <b>8</b> forms 5 hydrogen bonds (<b>ASN514</b>, <b>ASP424</b>, <b>ARG95</b>, <b>TYP68</b>, <b>LEU65</b>) while compound <b>6</b> forms 2 hydrogen bonds (<b>ASN514</b> and <b>SER422</b>). However, no H-bonding interaction occurs in the complex that involves ligands <b>9</b> and <b>3</b> despite their high binding energy (-8.2±0.1 Kcal/mol and -8.3±0.0 Kcal/mol respectively). Glucose oxidase can serve as a marker enzyme for<i> in vitro</i> antidiabetic activity evaluation of medicinal plants.


2022 ◽  
Author(s):  
Marius Walter ◽  
Irene P Chen ◽  
Albert Vallejo-Gracia ◽  
Ik-Jung Kim ◽  
Olga Bielska ◽  
...  

SARS-CoV-2 non-structural protein Nsp14 is a highly conserved enzyme necessary for viral replication. Nsp14 forms a stable complex with non-structural protein Nsp10 and exhibits exoribonuclease and N7-methyltransferase activities. Protein-interactome studies identified human sirtuin 5 (SIRT5) as a putative binding partner of Nsp14. SIRT5 is an NAD-dependent protein deacylase critical for cellular metabolism that removes succinyl and malonyl groups from lysine residues. Here we investigated the nature of this interaction and the role of SIRT5 during SARS-CoV-2 infection. We showed that SIRT5 stably interacts with Nsp14, but not with Nsp10, suggesting that SIRT5 and Nsp10 are parts of separate complexes. We found that SIRT5 catalytic domain is necessary for the interaction with Nsp14, but that Nsp14 does not appear to be directly deacylated by SIRT5. Furthermore, knock-out of SIRT5 or treatment with specific SIRT5 inhibitors reduced SARS-CoV-2 viral levels in cell-culture experiments. SIRT5 knock-out cells expressed higher basal levels of innate immunity markers and mounted a stronger antiviral response. Our results indicate that SIRT5 is a proviral factor necessary for efficient viral replication, which opens novel avenues for therapeutic interventions.


2022 ◽  
Author(s):  
Boris Sobolev ◽  
Lisa Kuramoto

Objectives Clinical guidelines favor coronary artery bypass grafting (CABG) over percutaneous coronary intervention (PCI) for patients with stable complex coronary disease. Yet the benefit of CABG as established in trials may not be generalizable to populations in which treatment method determines time to treatment, typically being longer for CABG. For cases in which the cardiac anatomy is suitable for either treatment, it is unclear whether it is appropriate to recommend CABG, which is likely to be delayed, if PCI can be performed sooner. This paper outlines an analytical framework for a policy analysis of the timing of coronary revascularization. Methods We constructed a thought experiment to examine whether time to treatment will influence the advantage of CABG. We substantiated the use of mediation analysis to estimate the extent to which differences in outcomes between CABG and PCI would change if times to CABG were the same as times to PCI. Results We designed a study that uses data from a population-based patient registry to obtain effect measures of mediation analysis: the total effect, the natural indirect effect, and the natural direct effect. The partitioning of the total effect will allow us to estimate the proportional reduction in the risk of an outcome if the time to CABG was similar to that of PCI. Interpretation Treatment recommendation, resource allocation and scheduling benchmarks will be guided by understanding the extent to which the time to treatment mediates the relation between revascularization method and outcome.


Author(s):  
Rekha Ravindran ◽  
Praveen Kumar PK ◽  
Sriram Kumar ◽  
Sujata Roy ◽  
Sakthi Abirami Gowthaman ◽  
...  

Background: Cardiovascular Diseases (CVDs) remain the leading cause of death worldwide, which urges for effective strategies of prevention and treatment. Withaferin-A (WFA), the key metabolite identified in Withania somnifera, has been known for its cardioprotective properties. Although it has been traditionally employed to treat cardiovascular ailments for several decades, its exact mechanism of action still remains unexplained Objective: The current study modelled and scored the interactions of WFA with nine prospective protein-targets associated with cardiovascular diseases through molecular docking and DSX-scoring. Methods: Molecular docking was carried out using Autodock and DSX-scoring was carried out using DSX standalone software. WFA was observed to favorably interact with six targets before DSX-based rescoring, but only with Poly (ADP-Ribose) Polymerase-1 and P2Y Purinoceptor-1 after DSX-based rescoring. The spatial orientation, physicochemical properties and structural features of Withaferin-A were compared with that of these approved drugs by pharmacophore modeling and hierarchical clustering Results: The results of molecular docking, DSX-based rescoring and complete pharmacophore modeling together revealed that PARP1 and P2Y1 receptor could be prospective targets of WFA for the treatment of CVD. Conclusion: Simulation using GROMACS has revealed that WFA forms a more stable complex with PARP1 and will be useful in developing the broad-spectrum drugs against cardiovascular diseases. Further computational studies through machine learning and network pharmacology methods can be carried out to improve Withaferin-A compound features by incorporating additional functional groups necessary for molecular recognition of the target genes in network responsible for cardiovascular diseases.


2021 ◽  
Vol 66 (1) ◽  
Author(s):  
Abhishek Srivastava ◽  
Vivek Sharma ◽  
Vinay Kumar Singh ◽  
Krishna Srivastava

Abstract. A fast, reproducible, and sensitive method is proposed for the kinetic determination of carbocisteine (CCys). The method depends on the inhibitory property of carbocisteine, which reduces the Hg2+ catalyzed substitution rate of cyanide from [Ru(CN)6]4- with N-R-salt (1-Nitroso-2-naphthol-3,6-disulfonic acid disodium salt) via forming a stable complex with Hg2+. Spectrophotometric measurements were carried out by recording the absorbance at 525 nm (λmax of [Ru(CN)5 Nitroso-R-Salt]3- complex) at a fixed time of 10 and 15 min under the optimized reaction conditions with [N-R-salt] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M and [Ru(CN)64-] = 4.25 × 10-5  M. With the proposed method, CCys can be determined quantitatively down to 3.0 × 10-6 M. This methodology can be effectively used for the rapid quantitative estimation of CCys in the pharmaceutical samples with good accuracy and reproducibility. The addition of common excipients in pharmaceuticals even up to 1000 times with [CCys] does not interfere significantly in the estimation of CCys.   Resumen. Se propone un método rápido, reproducibley sensible para la determinación cinética de la carbocisteina (CCys). El método depende de la propiedad inhibitoria de la carbocisteina que reduce la tasa de sustitución catalizada por Hg2+ del cianuro de [Ru(CN)6]4- con la sal N-R (sal disódica del ácido 1-Nitroso-2-naftol-3,6-disulfónico) mediante la formación de un complejo estable con Hg2+. Las mediciones espectrofotométricas se llevaron a cabo registrando la absorbancia a 525 nm (λmax del complejo [Ru(CN)5 Sal-Nitroso-R]3-) en un tiempo fijo de 10 y 15 min en las condiciones de reacción optimizadas con [sal-NR] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M y [Ru(CN)64-] = 4.25 × 10-5 M. Con el método propuesto, CCys se puede determinar cuantitativamente hasta 3,0 × 10-6 M. Esta metodología se puede utilizar eficazmente para la estimación cuantitativa rápida de CCys en las muestras farmacéuticas con buena precisión y reproducibilidad. La adición de excipientes comunes en productos farmacéuticos incluso hasta 1000 veces con [CCys] no interfiere significativamente en la estimación de CCys.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Elahe Karimi ◽  
Emran Heshmati ◽  
Khosrow Khalifeh

Abstract We compared the binding properties and dynamics of three experimentally reviewed isoforms of human dihydrofolate reductase (DHFR). The cytoplasmic variants including isoforms1 and 2 (iso1 and iso2) are produced by alternative splicing; while the mitochondrial form is located in the mitochondria. The iso1 as the canonical sequence contains 187 residues, and iso2 differs from the iso1, where it has 1–52 residues missing at the N-terminus of canonical sequence. Here, the structural models of the iso2 and mitochondrial forms were constructed by the MODELLER program using the crystal structure of the iso1 as the template. Bioinformatics analysis on ligand-bearing structures demonstrates that mitochondrial variant forms more stable complex with ligands compared with iso1 and 2, indicating their different binding properties. The root mean square fluctuation (RMSF) data suggest that C-terminus of iso1 contains two representative highly flexible fragments, while iso2 contains a highly flexible fragment at N-terminus end. Interestingly, both ends of mitochondrial variant have a degree of rigidity. Finally, the observation of differences in structural dynamics and binding properties predicts that the simultaneous existence of enzyme isoforms is a way to increase the speed of the enzyme maneuver in response to various environmental conditions. This prediction needs to be tested experimentally.


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