Nuclear Magnetic Resonance Spectroscopic Behaviour of Some Selective Natural Flavonoids: A Look Through

2020 ◽  
Vol 17 (2) ◽  
pp. 185-196
Author(s):  
Shyamal K. Jash ◽  
Dilip Gorai ◽  
Lalan C. Mandal ◽  
Rajiv Roy
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Natural Products ◽  
Magnetic Resonance ◽  
Hard Core ◽  
2D Nmr ◽  
Vital Role ◽  
Spectral Technique ◽  
Nmr Techniques ◽  
Significant Class ◽  
Nuclear Magnetic

Flavonoids are considered as a significant class of compounds among the natural products, exhibiting a variety of structural skeletons as well as multidirectional biological potentials. In structural elucidations of natural products, Nuclear Magnetic Resonance (NMR) spectroscopy has been playing a vital role; the technique is one of the sharpest tools in the hands of natural products chemists. The present resume deals with hard-core applications of such spectral technique, particularly in structural elucidation of flavonoids; different NMR techniques including 1H-NMR, 13C-NMR, and 2D-NMR [viz. 1H-1H COSY, COLOC, HMBC, HMQC] are described in detail.

A Combined Molecular Docking and Density Functional Theory Nuclear Magnetic Resonance Study of Trans-Dehydrocrotonin Interacting with COVID-19 Main Protease and Severe Acute Respiratory Syndrome Coronavirus 2 3C-Like Protease

2021 ◽  
Vol 21 (11) ◽  
pp. 5399-5407
Author(s):  
Evani Ferreira Cardoso ◽  
Thaís Forest Giacomello ◽  
Leandro Leal Rocha de Oliveira ◽  
Tiago Arouche da Silva ◽  
Antonio Maia de Jesus Chaves Neto ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Natural Products ◽  
Molecular Docking ◽  
Magnetic Resonance ◽  
Neutralizing Antibodies ◽  
Density Functional ◽  
Computational Method ◽  
Spike Protein ◽  
Experimental Result ◽  
Nuclear Magnetic

For the development of drugs that treat SARS-CoV-2, the fastest way is to find potential molecules from drugs already on the market. Unfortunately, there is currently no specific drug or treatment for COVID-19. Among all structural proteins in SARS-CoV, the spike protein is the main antigenic component responsible for inducing host immune responses, neutralizing antibodies, and/or protecting immunity against virus infection. Molecular docking is a technique used to predict whether a molecule will bind to another. It is usually a protein to another or a protein to a binding compound. Natural products are potential binders in several studies involving coronavirus. The structure of the ligand plays a fundamental role in its biological properties. The nuclear magnetic resonance technique is one of the most powerful tools for the structural determination of ligands from the origin of natural products. Nowadays, molecular modeling is an important accessory tool to experimentally got nuclear magnetic resonance data. In the present work, molecular docking studies aimed is to investigate the limiting affinities of trans-dehydrocrotonin molecule and to identify the main amino acid residues that could play a fundamental role in their mechanism of action of the SARS-CoV spike protein. Another aim of this work is all about to evaluate 10 hybrid functionalities, along with three base pairs using computational programs to discover which ones are more reliable with the experimental result the best computational method to study organic compounds. We compared the results between the mean absolute deviation (MAD) and root-mean-square deviation (RMSD) of the molecules, and the smallest number between them was the best result. The positions assumed by the ligands in the active site of the spike glycoprotein allow assuming associations with different local amino acids.

Elucidation of HIV‐1 5' Leader Secondary Structure Through Novel Long Range Nuclear Magnetic Resonance (NMR) Techniques

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Claudia Walker ◽  
Elisabeth Kan ◽  
Faith Davis ◽  
Jonathan Catazaro ◽  
Michael Summers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Secondary Structure ◽  
Long Range ◽  
Nmr Techniques ◽  
Hiv 1 ◽  
Nuclear Magnetic

Nuclear-Magnetic-Resonance Petrophysics in Thin Sand/Shale Laminations

SPE Journal ◽  
2010 ◽  
Vol 16 (02) ◽  
pp. 223-238 ◽  
Author(s):  
Chanh Cao Minh ◽  
Padmanabhan Sundararaman
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Bimodal Distribution ◽  
2D Nmr ◽  
Fluid Type ◽  
Antenna Aperture ◽  
Nmr Logging ◽  
Clay Layers ◽  
Gas Bearing ◽  
Nuclear Magnetic

Summary We discuss the use of nuclear-magnetic-resonance (NMR) logging in the petrophysical evaluation of thin sand/shale laminations. NMR helps detect thin beds, determine fluid type, establish the hydrocarbon type and volume if hydrocarbon is present, and, finally, determine the permeability of the sand layers (as opposed to that of the sand/shale system). Experiments were conducted on samples of 100% sand, 100% clay, and sand/clay layers with an NMR-logging tool at surface to verify the characteristic T2 bimodal relaxation distribution often observed in NMR logs that are acquired in thin beds. From the bimodal distribution, it is often possible to determine a cutoff to separate the productive sand layers from the shale layers and, with it, the porosity fraction of each component. Subsequently, the sand fraction, or net/gross ratio, can be estimated assuming that the 100%-sand porosity is known. Because gas, oil, and water have different NMR properties, fluid-typing techniques such as 2D NMR offer useful insights into the fluid type and properties in thin-layer sands. Because the laminations thickness is often less than the antenna aperture, the estimated permeability of the sand/ shale system will undercall the true permeability of the sand layers only. In this case, their permeability can be estimated quickly from Darcy's fluid-flow model. We show examples of thin sand/shale laminations that are oil-bearing and gas-bearing. In each case, the NMR detection was verified against borehole-imaging logs, and the fluid type in the sands was determined from multidimensional NMR analysis. The derived hydrocarbon volume was then compared with the results estimated from a triaxial induction tool. Permeability of the sand layers was also computed and compared to that of nearby thick sands. Core data in one well was used to validate NMR detection, porosity, permeability, and net sand thickness.

Comparison of 1-D and 2-D NMR techniques for screening earthworm responses to sub-lethal endosulfan exposure

2010 ◽  
Vol 7 (6) ◽  
pp. 524 ◽  
Author(s):  
Jimmy Yuk ◽  
Jennifer R. McKelvie ◽  
Myrna J. Simpson ◽  
Manfred Spraul ◽  
André J. Simpson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Organochlorine Pesticide ◽  
Environmental Exposure ◽  
Quantum Coherence ◽  
Metabolic Response ◽  
Powerful Approach ◽  
Nmr Techniques ◽  
And Control ◽  
Nuclear Magnetic

Environmental context The application of metabolomics from an environmental perspective depends on the analytical ability to discriminate minute changes in the organism resulting from exposure. In this study, 1-D and 2-D Nuclear Magnetic Resonance (NMR) experiments were examined to characterise the earthworm’s metabolic response to an organochlorine pesticide. 2-D NMR showed considerable improvement in discriminating exposed worms from controls and in identifying the metabolites responsible. This study demonstrates the potential of 2-D NMR in understanding subtle biochemical responses resulting from environmental exposure. Abstract Nuclear Magnetic Resonance (NMR) based metabolomics is a powerful approach to monitoring an organism’s metabolic response to environmental exposure. However, the discrimination between exposed and control groups, depends largely on the NMR technique chosen. Here, three 1-D NMR and three 2-D NMR techniques were investigated for their ability to discriminate between control earthworms (Eisenia fetida) and those exposed to a sub-lethal concentration of a commonly occurring organochlorine pesticide, endosulfan. Partial least-squares discriminant analysis found 1H–13C Heteronuclear Single Quantum Coherence (HSQC) spectroscopy to have the highest discrimination with a MANOVA value (degree of separation) three orders lower than any of the 1-D and 2-D NMR techniques. HSQC spectroscopy identified alanine, leucine, lysine, glutamate, glucose and maltose as the major metabolites of exposure to endosulfan, more than all the other techniques combined. HSQC spectroscopy in combination with a shorter 1-D experiment may prove to be an effective tool for the discrimination and identification of significant metabolites in organisms under environmental stress.

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