In silico molecular docking analysis for repurposing approved antiviral drugs against SARS-CoV-2 main protease

Developing a safe and effective antiviral treatment takes a decade, however, when it comes to the coronavirus disease (COVID-19), time is a sensitive matter to slow the spread of the pandemic. Screening approved antiviral drugs against COVID-19 would speed the process of finding therapeutic treatment. The current study examines commercially approved drugs to repurpose them against COVID-19 virus main protease using structure-based in-silico screening. The main protease of the coronavirus is essential in the viral replication and is involved in polyprotein cleavage and immune regulation, making it an effective target when developing the treatment. A Number of approved antiviral drugs were tested against COVID-19 virus using molecular docking analysis by calculating the free natural affinity of the binding ligand to the active site pocket and the catalytic residues without forcing the docking of the ligand to active site. COVID-19 virus protease solved structure (PDB ID: 6LU7) is targeted by repurposed drugs. The molecular docking analysis results have shown that the binding of Remdesivir and Mycophenolic acid acyl glucuronide with the protein drug target has optimal binding features supporting that Remdesivir and Mycophenolic acid acyl glucuronide can be used as potential anti-viral treatment against COVID-19 disease.     

肿瘤发生的细胞离子动态及其作为抗癌药标的综合效应

大量肿瘤细胞的有关研究表明,H+、Na+、Ca2+等细胞离子的动态对肿瘤发生起着关键作用.然而,单个离子作为代谢基础的作用是多方面的,其涉癌效果很不一致,有时还是相反的.因此,以控制单个离子动态作为抗癌药物的靶标,其效果并不理想.迄今对细胞离子的致癌作用的研究虽然是大量的,但均散见各章,缺少综合考虑.为此,本文简要介绍了上述离子的致癌作用,并探讨了以控制离子动态为药标,设计抗癌药物时应考虑的综合效应,供癌药物学研究者参考.     

Dopamine Receptor Microdomains Involved in Molecular Recognition and the Regulation of Drug Affinity and Function

A cationic protonatable amine moiety on dopaminergic ligands forms a high affinity reinforced ionic bond with an anionic aspartic acid at position 3.32 of dopamine receptors. When present, catechol hydroxyls of the ligands form hydrogen bonds with serines at position 5.42, 5.43, and 5.46, and this network of hydrogen bonds serves to orient ligands in the binding-site crevice and increase their binding affinity. A steric clash between aromatic moieties of the ligands and aromatic amino acids of the receptor (e.g., H6.55, F6.52 or F6.51 and W6.48) is likely to be propagated in domino-like fashion along the length of TM6, which is believed to trigger activation of the receptor. Specifically, it is the change in the conformation of W6.48 from an orientation perpendicular to the plane of the lipid membrane to one that is parallel that is believed to result in activation. Molecular determinants that mediate the D4/D2-selectivity of many extremely D4-selective 1,4-DAP ligands, include a nonconserved cluster of bulky amino acids at the TM2/TM3 interface (positions 2.61, 3.28 and 3.29).     

Two new anti-plasmodial flavonoid glycosides from Duranta repens

The CHCl₃-soluble fraction of the whole plant of Duranta repens showed anti-plasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum, with IC₅₀ values of 8.5?±?0.9 and 10.2?±?1.5?μg/mL, respectively. From this fraction, two new flavonoid glycosides, 7-O-α-d-glucopyranosyl-3,4′-dihydroxy-3′-(4-hydroxy-3-methylbutyl)-5,6-dimethoxyflavone (1) and 7-O-α-d-glucopyranosyl(6′′′-p-hydroxcinnamoyl)-3,4′-dihydroxy-3′-(4-hydroxy-3-methylbutyl)-5,6-dimethoxyflavone (2), along with five known flavonoids, 3,7,4′-trihydroxy-3′-(4-hydroxy-3-methylbutyl)-5,6-dimethoxyflavone (3), 3,7-dihydroxy-3′-(4-hydroxy-3-methylbutyl)-5,6,4′-trimethoxyflavone (4), 5,7-dihydroxy-3′-(2-hydroxy-3-methyl-3-butenyl)-3,6,4′-trimethoxyflavone (5), 3,7-dihydroxy-3′-(2-hydroxy-3-methyl-3-buten-yl)-5,6,4′-trimethoxyflavone (6), and 7-O-α-d-glucopyranosyl-3,5-dihydroxy-3′-(4′′-acetoxy-3′′-methylbutyl)-6,4′-dimethoxyflavone (7), have been isolated as anti-plasmodial principles. Their structures were deduced by spectroscopic analysis including 1D and 2D NMR techniques. The compounds (1–7) showed potent anti-plasmodial activities against D6 and W2 strains of Plasmodium falciparum, with IC₅₀ values in the range of 5.2–13.5?μM and 5.9–13.1?μM, respectively.     

In vitro effects of some drugs on human erythrocyte glutathione reductase

The effects of ketotifen, meloxicam, phenyramidol–HCl and gadopentetic acid on the enzyme activity of GR were studied using human erythrocyte glutathione reductase (GR) enzymes in vitro. The enzyme was purified 209-fold from human erythrocytes in a yield of 19% with 0.31?U/mg. The purification procedure involved the preparation of haemolysate, ammonium sulphate precipitation, 2′′,5′-ADP Sepharose 4B affinity chromatography and Sephadex G-200 gel filtration chromatography. Purified enzyme was used in the in vitro studies. In the in vitro studies, IC₅₀ values and K_i constants were 0.012?mM and 0.0008?±?0.00021?mM for ketotifen; 0.029?mM and 0.0061?±?0.00127?mM for meloxicam; 0.99?mM and 0.4340?±?0.0890?mM for phenyramidol–HCl; 138?mM and 28.84?±?4.69?mM for gadopentetic acid, respectively, showing the inhibition effects on the purified enzyme. Phenyramidol–HCl showed competitive inhibition, whereas the others showed non-competitive inhibition.     

The effect of substituted thiophene and benzothiophene derivates on PPARγ expression and glucose metabolism

Eighteen substituted thiophene and benzothiophene derivatives were studied for their effects on peroxisome proliferator-activated receptor γ (PPARγ) in HepG2 cells. Three derivatives (compounds 5, 120.97%; 15, 102.14%; and 17, 113.82%) were found to transactivate PPARγ in vitro. By comparison, the positive control rosiglitazone (Ros) transactivated PPARγ by 311.53%. The three compounds were studied for their effects on glucose metabolism in vivo in KK/Ay diabetic mice. In vivo, the 2-(β-carbonyl/sulfonyl) butyryl-thiophene compounds 5 and 15 significantly decreased blood glucose levels (compounds 5, to?<?15.6?mmol/L; 15, to?<?10?mmol/L), improved glucose tolerance, improved impaired pancreatic islet β-cells, and lowered serum insulin levels.     

International law,public health,and the meanings of pharmaceuticalization

Recent social science scholarship has employed the term “pharmaceuticalization” in analyses of the production, circulation and use of drugs. In this paper, we seek to open up further discussion of the scope, limits and potential of this as an analytical device through consideration of the role of law and legal processes in directing pharmaceutical flows. To do so, we synthesize a range of empirical and conceptual work concerned with the relationships between access to medicines and intellectual property law. This paper suggests that alongside documenting the expansion or reduction in demand for particular drugs, analysts of pharmaceuticalization attend to the ways in which socio-legal developments change (or not) the identities of drugs, and the means through which they circulate and come to be used by states and citizens. Such scholarship has the potential to more precisely locate the biopolitical processes that shape international agendas and targets, form markets, and produce health.     

Exosome DNA: Critical regulator of tumor immunity and a diagnostic biomarker

Nanosized cellular vesicles “exosome” contains a variety of biological cargo including DNA fragments from cell-of-origin. Despite its biological stability and clinical utility in tumor diagnosis, exosome DNA (ExoDNA) is very little studied as compare with exosome RNA. Cytoplasmic accumulation of damaged DNA from nucleus and mitochondria often leads to its packaging in exosomes by yet unknown pathways. ExoDNA modulates tumor immunity via paracrine interactions and activation of cytosolic DNA sensor pathways, for example, STING, cGAS, and so forth in specific immune cell subsets. In addition to priming tumor immunity, ExoDNA is also emerging as a critical regulator of check-point immunotherapy. As a useful diagnostic biomaterial, ExoDNA contains a variety of clinically relevant tumor-specific mutations representing multiple genes (e.g., EGFR, BRAF, RAS, IDH, and HER2), thus making it a promising “liquid biopsy” material for therapy recommendations. Hence, ExoDNA in addition to tumor immunity modulation, is also emerging as a suitable diagnostic material for personalized therapy in cancer. Here, we review the current status of ExoDNA research and its potential uses in tumor biology.