scholarly journals Antimicrobial activity of methanolic extracts of Vernonia cinerea against Xanthomonas oryzae and identification of their compounds using in silico techniques

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252759
Author(s):  
Tushar Joshi ◽  
Satish Chandra Pandey ◽  
Priyanka Maiti ◽  
Manish Tripathi ◽  
Ashutosh Paliwal ◽  
...  

Bacterial Leaf Blight (BLB) disease is an extremely ruinous disease in rice, caused by Xanthomonas oryzae pv. oryzae (Xoo). Although various chemicals are available to manage BLB, they are toxic to the environment as well as humans. Hence there is a need to develop new pesticides as alternatives to hazardous chemicals. Therefore, a study was carried out to discover new potent natural pesticides against Xoo from different solvent extracts of Vernonia cinerea. Among all the fractions, the methanolic extract showed the highest inhibition zone. Further, to gain mechanistic insight of inhibitory action, 40 molecules of methanolic extracts were subjected for in silico study against two enzymes D-alanine—D-alanine ligase (Ddl) and Peptide deformylase (PDF). In silico study showed Rutin and Methanone, [1,4-dimethyl-7-(1- methylethyl)-2- azulenyl]phenyl have a good binding affinity with Ddl while Phenol, 2,4-bis(1-phenylethyl)- and 1,2-Benzenedicarboxylic acid, diisooctyl ester showed an excellent binding affinity to PDF. Finally, the system biology approach was applied to understand the agrochemical’s effect in the cell system of bacteria against both the enzymes. Conclusively, these four-hit compounds may have strong potential against Xoo and can be used as biopesticides in the future.

Author(s):  
Yevheniia Velihina ◽  
Nataliya Obernikhina ◽  
Stepan Pilyo ◽  
Maryna Kachaeva ◽  
Oleksiy Kachkovsky ◽  
...  

The binding affinity of model aromatic amino acids and heterocycles and their derivatives condensed with pyridine were investigated in silico and are presented in the framework of fragment-to-fragment approach. The presented model describes interaction between pharmacophores and biomolecules. Scrupulous data analysis shows that expansion of the π-electron system by heterocycles annelation causes the shifting up of high energy levels, while the appearance of new the dicoordinated nitrogen atom is accompanied by decreasing of the donor-acceptor properties. Density Functional Theory (DFT) wB97XD/6-31(d,p)/calculations of π-complexes of the heterocycles 1-3 with model fragments of aromatic amino acids, which were formed by π-stack interaction, show an increase in the stabilization energy of π-complexes during the moving from phenylalanine to tryptophan. DFT calculation of pharmacophore complexes with model proton-donor amino acid by the hydrogen bonding mechanism (H-B complex) shows that stabilization energy (DE) increases from monoheterocycles to their condensed derivatives. The expansion of the π-electron system by introducing phenyl radicals to the oxazole cycle as reported earlier [18] leads to a decrease in the stabilization energy of the [Pharm-BioM] complexes in comparison with the annelated oxazole by the pyridine cycle.


2020 ◽  
Author(s):  
Mallikarjuna Nimgampalle ◽  
Vasudharani Devanthan ◽  
Ambrish Saxena

Recently Chloroquine and its derivative Hydroxychloroquine have garnered enormous interest amongst the clinicians and health authorities’ world over as a potential treatment to contain COVID-19 pandemic. The present research aims at investigating the therapeutic potential of Chloroquine and its potent derivative Hydroxychloroquine against SARS-CoV-2 viral proteins. At the same time we have screened some chemically synthesized derivatives of Chloroquine and compared their binding efficacy with chemically synthesized Chloroquine derivatives through <i>in silico</i>approaches. For the purpose of the study, we have selected some essential viral proteins and enzymes implicated in SARS-CoV-2 replication and multiplication as putative drug targets.<br>


2021 ◽  
Vol 12 ◽  
Author(s):  
Brahmaiah Pendyala ◽  
Ankit Patras ◽  
Chandravanu Dash

In the 21st century, we have witnessed three coronavirus outbreaks: SARS in 2003, MERS in 2012, and the ongoing pandemic coronavirus disease 2019 (COVID-19). The search for efficient vaccines and development and repurposing of therapeutic drugs are the major approaches in the COVID-19 pandemic research area. There are concerns about the evolution of mutant strains (e.g., VUI – 202012/01, a mutant coronavirus in the United Kingdom), which can potentially reduce the impact of the current vaccine and therapeutic drug development trials. One promising approach to counter the mutant strains is the “development of effective broad-spectrum antiviral drugs” against coronaviruses. This study scientifically investigates potent food bioactive broad-spectrum antiviral compounds by targeting main protease (Mpro) and papain-like protease (PLpro) proteases of coronaviruses (CoVs) using in silico and in vitro approaches. The results reveal that phycocyanobilin (PCB) shows potential inhibitor activity against both proteases. PCB had the best binding affinity to Mpro and PLpro with IC50 values of 71 and 62 μm, respectively. Also, in silico studies with Mpro and PLpro enzymes of other human and animal CoVs indicate broad-spectrum inhibitor activity of the PCB. As with PCB, other phycobilins, such as phycourobilin (PUB), phycoerythrobilin (PEB), and phycoviolobilin (PVB) show similar binding affinity to SARS-CoV-2 Mpro and PLpro.


ALCHEMY ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 33-40
Author(s):  
Atika Umi Hanif ◽  
Prima Agusti Lukis ◽  
Arif Fadlan

 In silico technique is widely used for drug discovery because it can predict the conformation of ligands in protein macromolecules and it can calculate the binding affinity. The energy minimization is carried out to make the ligand more stable near the initial state during molecular docking process. The Merck Molecular Force Field (MMFF94) is one type of energy minimization process often used in organic compounds. The molecular docking of substituted oxindole derivatives on indoleamine macromolecules 2,3-dioxygenase (IDO-1, PDB: 2D0T) by MMFF94 minimization operated by MarvinSketch and Open Babel in PyRx showed different results. The binding affinity energy obtained was also quite different, but the ligands have the same conformation and bind the same residue with slightly different bond distances. Keywords: Molecular docking, energy minimization, substituted oxindole, Merck Molecular Force Field 94  Teknik in silico banyak digunakan untuk penemuan senyawa obat karena dapat memprediksi konformasi suatu ligan dalam makromolekul protein dan mampu menghitung nilai afinitas ikatan. Proses minimisasi energi dilakukan untuk menjadikan ligan lebih stabil mendekati keadaan awal selama penambatan molekular berlangsung. Merck Molecular Force Field (MMFF94) adalah salah satu jenis persamaan minimisasi energi yang sering digunakan pada senyawa organik. Hasil pengujian pengaruh minimisasi energi dengan MMFF94 menggunakan program MarvinSketch dan Open Babel dalam PyRx pada turunan oksindola tersubstitusi alkil terhadap makromolekul 2,3-dioxygenase indoleamine (IDO-1, PDB: 2D0T) menunjukkan hasil dengan nilai yang berbeda. Energi afinitas ikatan yang didapatkan juga cukup berbeda, namun ligan memiliki konformasi yang sama dan mengikat residu yang sama dengan jarak ikatan yang sedikit berbeda. Kata kunci: Penambatan molekular, minimisasi energi, oksindola tersubstitusi, Merck Molecular Force Field 94


Author(s):  
Aldina Amalia Nur Shadrina ◽  
Yetty Herdiyati ◽  
Ika Wiani ◽  
Mieke Hemiawati Satari ◽  
Dikdik Kurnia

Background: Streptococcus sanguinis can contribute to tooth demineralization, which can lead to dental caries. Antibiotics used indefinitely to treat dental caries can lead to bacterial resistance. Discovering new antibacterial agents from natural products like Ocimum basilicum will help combat antibiotic resistance. In silico analysis (molecular docking) can help determine the lead compound by studying the molecular interaction between the drug and the target receptor (MurA enzyme and DNA gyrase). It is a potential candidate for antibacterial drug development. Objective: The research objective is to isolate the secondary metabolite of O. basilicum extract that has activity against S. sanguinis through in vitro and in silico analysis. Methods: n-Hexane extract of O. basilicum was purified by combining column chromatography with bioactivity-guided. The in vitro antibacterial activity against S. sanguinis was determined using the disc diffusion and microdilution method, while molecular docking simulation of nevadensin (1) with MurA enzyme and DNA gyrase was performed used PyRx 0.8 program. Results: Nevadensin from O. basilicum was successfully isolated and characterized by spectroscopic methods. This compound showed antibacterial activity against S. sanguinis with MIC and MBC values of 3750 and 15000 μg/mL, respectively. In silico analysis showed that the binding affinity to MurA was -8.5 Kcal/mol, and the binding affinity to DNA gyrase was -6.7 Kcal/mol. The binding of nevadensin-MurA is greater than fosfomycin-MurA. Otherwise, Nevadensin-DNA gyrase has a weaker binding affinity than fluoroquinolone-DNA gyrase and chlorhexidine-DNA gyrase. Conclusion: Nevadensin showed potential as a new natural antibacterial agent by inhibiting the MurA enzyme rather than DNA gyrase.


Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5885
Author(s):  
Tanzina Sharmin Nipun ◽  
Alfi Khatib ◽  
Zalikha Ibrahim ◽  
Qamar Uddin Ahmed ◽  
Irna Elina Redzwan ◽  
...  

Psychotria malayana Jack has traditionally been used to treat diabetes. Despite its potential, the scientific proof in relation to this plant is still lacking. Thus, the present study aimed to investigate the α-glucosidase inhibitors in P.malayana leaf extracts using a metabolomics approach and to elucidate the ligand–protein interactions through in silico techniques. The plant leaves were extracted with methanol and water at five various ratios (100, 75, 50, 25 and 0% v/v; water–methanol). Each extract was tested for α-glucosidase inhibition, followed by analysis using liquid chromatography tandem to mass spectrometry. The data were further subjected to multivariate data analysis by means of an orthogonal partial least square in order to correlate the chemical profile and the bioactivity. The loading plots revealed that the m/z signals correspond to the activity of α-glucosidase inhibitors, which led to the identification of three putative bioactive compounds, namely 5′-hydroxymethyl-1′-(1, 2, 3, 9-tetrahydro-pyrrolo (2, 1-b) quinazolin-1-yl)-heptan-1′-one (1), α-terpinyl-β-glucoside (2), and machaeridiol-A (3). Molecular docking of the identified inhibitors was performed using Auto Dock Vina software against the crystal structure of Saccharomyces cerevisiae isomaltase (Protein Data Bank code: 3A4A). Four hydrogen bonds were detected in the docked complex, involving several residues, namely ASP352, ARG213, ARG442, GLU277, GLN279, HIE280, and GLU411. Compound 1, 2, and 3 showed binding affinity values of −8.3, −7.6, and −10.0 kcal/mol, respectively, which indicate the good binding ability of the compounds towards the enzyme when compared to that of quercetin, a known α-glucosidase inhibitor. The three identified compounds that showed potential binding affinity towards the enzymatic protein in molecular docking interactions could be the bioactive compounds associated with the traditional use of this plant.


Author(s):  
Nishadh Abubakker

Objective: The objective of this study was to evaluate the enzymic and non-enzymic antioxidant levels in various solvent extracts of Vernonia cinerea leaves.Methods: The fine powder of leaf (180 g) was extracted successively with methanol, ethanol, petroleum ether (40–60°C), benzene, acetone, ethyl acetate, chloroform, and aqueous in a Soxhlet extractor for 18 h. The extracts were concentrated under reduced pressure at low temperature (40– 50°C), and the extracts were analyzed for the antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), peroxidise, glutathione S-transferase (GST), glutathione peroxidase (GPx), polyphenol oxidase, glutathione (GSH) reductase, and glucose-6-phosphate dehydrogenase and non-enzymic antioxidants such as Vitamin A, C, E, reduced GSH, and total phenol.Results: Significant activities of enzymic antioxidants such as CAT (23.68 μ mole of H2O2 decomposed/min/mg protein, SOD (19.75 inhibition of 50% nitrite form/min/mg protein), and GST (73.28 μ mole of 1-chloro-2,4-dinitrobenzene conjugate formed/min) were observed higher in the methanolic extracts. Whereas, ethanolic extract exhibits maximum activity of GPx (1.054 μ mole of GSH utilized/min) and Px (102.1 μ mole of pyrogallol oxidized/ min/mg protein). Total GSH (172.3 μM/g), Vitamin E (23.76 μM/g), and total phenols were significantly predominant in the ethanolic extracts followed by methanol and ethyl acetate extracts.Conclusion: V. cinerea seems to be a promising plant in respect of its antioxidant potential, there is a lot more to be done to understand the mechanisms behind these effects as well as to employ them as possible therapeutic agents.


Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2949
Author(s):  
Yoshiro Hanyu ◽  
Yuto Komeiji ◽  
Mieko Kato

Monoclonal antibodies with high affinity and specificity are essential for research and clinical purposes, yet remain difficult to produce. Agretope peptides that can potentiate antigen-specific antibody production have been reported recently. Here, we screened in silico for peptides with higher affinity against the agretope binding pocket in the MHC-II. The screening was based on the 3D crystal structure of a complex between MHC-II and a 14-mer peptide consisting of ovalbumin residues 323–339. Using this 14-mer peptide as template, we constructed a library of candidate peptides and screened for those that bound tightly to MHC-II. Peptide sequences that exhibited a higher binding affinity than the original ovalbumin peptide were identified. The peptide with the highest binding affinity was synthesized and its ability to boost antigen-specific antibody production in vivo and in vitro was assessed. In both cases, antigen-specific IgG antibody production was potentiated. Monoclonal antibodies were established by in vitro immunization using this peptide as immunostimulant, confirming the usefulness of such screened peptides for monoclonal antibody production.


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