Gel-to-sol transition of 13C-labeled (1 → 3)-β-d-glucan, 13C-SSG, assessed by 13C nuclear magnetic resonance (13C-NMR) spectroscopy

1995 ◽  
Vol 270 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Masahiro Suda ◽  
Naohito Ohno ◽  
Yoshiyuki Adachi ◽  
Toshiro Yadomae
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

scholarly journals Determination of the 1,3- and 2-Positional Distribution of Fatty Acids in Olive Oil Triacylglycerols by 13C Nuclear Magnetic Resonance Spectroscopy

2006 ◽  
Vol 89 (4) ◽  
pp. 1071-1076 ◽  
Author(s):  
Giovanna Vlahov
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fatty Acid ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Olive Oil ◽  
Distribution Pattern ◽  
Random Distribution ◽  
Linear Models ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

Abstract Linear models were selected from a large data set acquired for Italian olive oil samples by quantitative 13C nuclear magnetic resonance (NMR) spectroscopy with distortionless enhancement by polarization transfer (DEPT). The models were used to determine the composition of the 2 fatty acid pools esterifying the 1,3- and 2-positions of triacylglycerols. The linear models selected proved that the 1,3- and 2-distribution of saturated, oleate, and linoleate chains in olive oil triacylglycerols deviated from the random distribution pattern to an extent that depended on the concentration of the fatty acid in the whole triacylglycerol. To calculate the fatty acid composition of the 1,3- and 2-positions of olive oil triacylglycerols, the equations of the selected linear models were applied to the fatty acid percentages determined by gas chromatography. These data were compared with the values predicted by the computer method (used to determine the theoretical amounts of triacylglycerols), which is based on the 1,3-random-2-random theory of the fatty acid distribution in triacylglycerols. The biggest differences were found in the linoleate chain, which is the chain that deviated the most from a random distribution pattern. The results confirmed that the 1,3-random-2-random distribution theory provides an approximate method for determining the structure of triacylglycerols; however, the linear models calculated by the direct method that applies 13C NMR spectroscopy represent a more precise measurement of the composition of the 2 fatty acid pools esterifying the 1,3- and 2-positions of triacylglycerols.

scholarly journals Dereplication of Natural Extracts Diluted in Glycerin: Physical Suppression of Glycerin by Centrifugal Partition Chromatography Combined with Presaturation of Solvent Signals in 13C-Nuclear Magnetic Resonance Spectroscopy

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5061
Author(s):  
Marine Canton ◽  
Jane Hubert ◽  
Stéphane Poigny ◽  
Richard Roe ◽  
Yves Brunel ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
13C Nmr ◽  
Model Mixture ◽  
Partition Chromatography ◽  
Centrifugal Partition Chromatography ◽  
Chemical Profiling ◽  
Natural Extracts ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

For scientific, regulatory, and safety reasons, the chemical profile knowledge of natural extracts incorporated in commercial cosmetic formulations is of primary importance. Many extracts are produced or stabilized in glycerin, a practice which hampers their characterization. This article proposes a new methodology for the quick identification of metabolites present in natural extracts when diluted in glycerin. As an extension of a 13C nuclear magnetic resonance (NMR) based dereplication process, two complementary approaches are presented for the chemical profiling of natural extracts diluted in glycerin: A physical suppression by centrifugal partition chromatography (CPC) with the appropriate biphasic solvent system EtOAc/CH3CN/water 3:3:4 (v/v/v) for the crude extract fractionation, and a spectroscopic suppression by presaturation of 13C-NMR signals of glycerin applied to glycerin containing fractions. This innovative workflow was applied to a model mixture containing 23 natural metabolites. Dereplication by 13C-NMR was applied either on the dry model mixture or after dilution at 5% in glycerin, for comparison, resulting in the detection of 20 out of 23 compounds in the two model mixtures. Subsequently, a natural extract of Cedrus atlantica diluted in glycerin was characterized and resulted in the identification of 12 metabolites. The first annotations by 13C-NMR were confirmed by two-dimensional NMR and completed by LC-MS analyses for the annotation of five additional minor compounds. These results demonstrate that the application of physical suppression by CPC and presaturation of 13C-NMR solvent signals highly facilitates the quick chemical profiling of natural extracts diluted in glycerin.

scholarly journals Qualitative and Quantitative Analysis of Heavy Crude Oil Samples and Their SARA Fractions with 13C Nuclear Magnetic Resonance

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 995
Author(s):  
Ilfat Rakhmatullin ◽  
Sergey Efimov ◽  
Vladimir Tyurin ◽  
Marat Gafurov ◽  
Ameen Al-Muntaser ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Crude Oil ◽  
Functional Groups ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
Sara Fractions ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) approaches have unique advantages in the analysis of crude oil because they are non-destructive and provide information on chemical functional groups. Nevertheless, the correctness and effectiveness of NMR techniques for determining saturates, aromatics, resins, and asphaltenes (SARA analysis) without oil fractioning are still not clear. In this work we compared the measurements and analysis of high-resolution 13C NMR spectra in B0 ≈ 16.5 T (NMR frequency of 175 MHz) with the results of SARA fractioning for four various heavy oil samples with viscosities ranging from 100 to 50,000 mPa·s. The presence of all major hydrocarbon components both in crude oil and in each of its fractions was established quantitatively using NMR spectroscopy. Contribution of SARA fractions in the aliphatic (10–60 ppm) and aromatic (110–160 ppm) areas of the 13C NMR spectra were identified. Quantitative fractions of aromatic molecules and oil functional groups were determined. Aromaticity factor and the mean length of the hydrocarbon chain were estimated. The obtained results show the feasibility of 13C NMR spectroscopy for the express analysis of oil from physical properties to the composition of functional groups to follow oil treatment processes.

scholarly journals Design, Synthesis, Characterization, Biological Activity and ADME Study of New 5-arylidene-4-Thiazolidinones Derivatives Having

2019 ◽  
pp. 77-88
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Chloroacetic Acid ◽  
13C Nmr Spectroscopy ◽  
Proton Nuclear Magnetic Resonance ◽  
Design Synthesis ◽  
Antibacterial And Antifungal ◽  
Adme Study ◽  
Nuclear Magnetic

New series of Nabumetone containing 5-arylidene-4-thiazolidinones pharmacophore as in compounds 3(a-e) were designed and synthesized by using nabumetone and hydrazinethiocarboamide to synthesize compound (1) (Schiff base), next step compound (1) will react with chloroacetic acid and anhydrous sodium acetate in order to synthesize compound (2) containing 4-thiazolidinone ring this compound will react with 4-benzaldehyde derivatives in the presence of basic media such as piperidine to form compounds 3(a-e). The structures of new intermediate and final synthesized compounds were detected by determination of physical properties (melting points). The structure of synthesized compounds has been confirmed by FT-IR spectroscopy, proton nuclear magnetic resonance (1H-NMR) spectroscopy and carbon 13 nuclear magnetic resonance (13C-NMR) spectroscopy the final synthesized compounds were also screened for their antibacterial and antifungal activity.

scholarly journals 13C Nuclear Magnetic Resonance Phytochemical Profiling of the In Vitro Antidiabetic Potential of Vitex negundo L.

2019 ◽  
Vol 4 (1) ◽  
pp. 181
Author(s):  
Myrnille Joy B. Zabala ◽  
Lolita G. Lagurin ◽  
Fabian M. Dayrit
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Ethyl Acetate ◽  
13C Nmr ◽  
Structural Features ◽  
Vitex Negundo ◽  
13C Nuclear Magnetic Resonance ◽  
Glucose Diffusion ◽  
Nuclear Magnetic

Vitex negundo has been known since ancient times as a medicinal plant. The objective of this study is to investigate the effect of methanol and ethanol extracts, and ethyl acetate, chloroform and aqueous fractions of Vitex negundo using an in vitro model to test glucose diffusion and to determine the phytochemical profile of the extracts and fractions using 13C nuclear magnetic resonance (NMR) spectroscopy. The chloroform fractions, ethyl acetate-EtOH and ethyl acetate-MeOH gave the highest inhibitory effect on both the diffusion activities in vitro. Retardation of glucose diffusion suggests that negundo has the potential to lower postprandial glucose. Correlation analysis of the 13C NMR profile with retardation activity suggests that compounds containing glycosidic residues may be responsible for the glucose retardation activity. This is the first example where activity has been correlated with specific structural features of compounds from a crude extract using 13C NMR chemical shifts to assist in the identification of active compounds.

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