Qualitative and Quantitative Analysis of Amygdalin Using NMR Spectroscopy

Turczan, John W.; Medwick, Thomas

doi:10.1080/00032717708059224

Cited by 16 publications

(9 citation statements)

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“…The assigned chemical shifts of the single peaks integrated for quantification by 1 H NMR for each metabolite are vanillin – δ 9.73 (s), glucovanillin – δ 9.82 (s), p -hydroxybenzaldehyde – δ 9.75 (s), vanillyl alcohol – δ 3.87 (s), vanillic acid – δ 3.89 (s), p -hydroxybenzoic acid – δ 6.90 (d, J = 8.8 Hz), sucrose – δ 5.40 (d, J = 3.6 Hz), glucose (two peaks integrated) – δ 4.63 (d, J = 8.0 Hz), δ 5.18 (d, J = 3.7 Hz) and fructose - δ4.03 (H-8, dd, J = 12.9,1.0 Hz) [10, 36, 37]. …”

Section: Methodsmentioning

confidence: 99%

“…The amounts of metabolites were calculated using the 1 H NMR equation as in Turczan and Medwick [ 37 ] as follows: nx = ny (Ix / Iy) (Ny / Nx) where nx : Number of moles of unknown; ny : Number of moles of TMSP; Nx : Number of protons of unknown; Ny : Number of protons of TMSP; Ix : Integration of peak of unknown and Iy : Integration of peak of TMSP (9 protons, 2.90 × 10 −4 mol). The assigned chemical shifts of the single peaks integrated for quantification by 1 H NMR for each metabolite are vanillin – δ 9.73 (s), glucovanillin – δ 9.82 (s), p -hydroxybenzaldehyde – δ 9.75 (s), vanillyl alcohol – δ 3.87 (s), vanillic acid – δ 3.89 (s), p -hydroxybenzoic acid – δ 6.90 (d, J = 8.8 Hz), sucrose – δ 5.40 (d, J = 3.6 Hz), glucose (two peaks integrated) – δ 4.63 (d, J = 8.0 Hz), δ 5.18 (d, J = 3.7 Hz) and fructose - δ4.03 (H-8, dd, J = 12.9,1.0 Hz) [ 10 , 36 , 37 ].…”

Section: Methodsmentioning

confidence: 99%

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Fungal endophytes of Vanilla planifolia across Réunion Island: isolation, distribution and biotransformation

et al. 2015

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BackgroundThe objective of the work was to characterize fungal endophytes from aerial parts of Vanilla planifolia. Also, to establish their biotransformation abilities of flavor-related metabolites. This was done in order to find a potential role of endophytes on vanilla flavors.ResultsTwenty three MOTUs were obtained, representing 6 fungal classes. Fungi from green pods were cultured on mature green pod based media for 30 days followed by 1H NMR and HPLC-DAD analysis. All fungi from pods consumed metabolized vanilla flavor phenolics. Though Fusarium proliferatum was recovered more often (37.6 % of the isolates), it is Pestalotiopsis microspora (3.0 %) that increased the absolute amounts (quantified by 1H NMR in μmol/g DW green pods) of vanillin (37.0 × 10−3), vanillyl alcohol (100.0 × 10−3), vanillic acid (9.2 × 10−3) and p-hydroxybenzoic acid (87.9 × 10−3) by significant amounts.ConclusionsAll plants studied contained endophytic fungi and the isolation of the endophytes was conducted from plant organs at nine sites in Réunion Island including under shade house and undergrowth conditions. Endophytic variation occured between cultivation practices and the type of organ. Given the physical proximity of fungi inside pods, endophytic biotransformation may contribute to the complexity of vanilla flavors.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0522-5) contains supplementary material, which is available to authorized users.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Fungal endophytes of Vanilla planifolia across Réunion Island: isolation, distribution and biotransformation

et al. 2015

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“…25 In the past three decades, there has been growing interest in quantitative NMR (qNMR) 26,27 with the significant contribution of Turczan and Medwick. 28 For complex mixtures with overlapped peaks or very weak amounts of molecules, quantitative 1D 1 H NMR spectroscopy was not sufficient, 29 giving rise to the development of 2D qNMR spectroscopy with heteronuclear single quantum coherence (HSQC experiments), 30 homonuclear total correlation spectroscopy (TOCSY) experiments, 31 and a combination of both. 32 This kind of approach, developed so far for liquid NMR applications, has not been developed to our knowledge in a context of a semisolid nonanisotropic environment like the epidermis.…”

Section: ■ Introductionmentioning

confidence: 99%

In Situ Alkylation of Reconstructed Human Epidermis by Methyl Methanesulfonate: A Quantitative HRMAS NMR Chemical Reactivity Mapping

Srour

Moussallieh

Elbayed

et al. 2020

Chem. Res. Toxicol.

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Allergic Contact Dermatitis (ACD) is a reaction of the immune system resulting from skin sensitization to an exogenous hazardous chemical and leading to the activation of antigenspecific T-lymphocytes. The adverse outcome pathway (AOP) for skin sensitization identified four key events (KE) associated to the mechanisms of this pathology, the first one being the ability of skin chemical sensitizers to modify epidermal proteins to form antigenic structures that will further trigger the immune system. So far, these interactions have been studied in solution using model nucleophiles such as amino acids or peptides. As a part of our efforts to better understand chemistry taking place during the sensitization process, we have developped a method based on the use of high resolution magic angle spinning (HRMAS) NMR to monitor in situ the reactions of 13 C substituted chemical sensitizers with nucleophilic amino acids of epidermal proteins in reconstructed human epidermis. A quantitative approach, developed so far for liquid NMR applications, has not been developed to our knowledge in a context of a semi-solid non-anisotropic environment like the epidermis. We now report a quantitative chemical reactivity mapping of methyl methanesulfonate, a sensitizing methylating agent, in reconstructed human epidermis by qHRMAS NMR. First, the haptenation process appeared to be much faster in RHE than in solution with a maximum concentration of adducts reached between 4 to 8 hours. Second, it was observed that the concentration of cysteine adducts did not significantly increase with the dose (2.07 nmol/mg at 0.4 M and 2.14 nmol/mg at 1 M) nor with the incubation time (maximum of 2.27 nmol/mg at 4 h) compared to other nucleophiles indicating a fast reaction and a potential saturation of targets. Third, when increasing the exposure dose we observed an increase of adducts up to 12.5 nmol/mg of RHE, excluding Cystein adducts, for 3112 µg/cm 2 (1M solution) of ( 13 C)MMS. This methodology applied to other skin sensitizers could allow to better understand the potential links between the amount of chemical modifications formed in the epidermis in relation with exposure and the sensitization potency.

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“…Amygdalin is a by-product of the fruit industry, and a naturally occurring glycoside found in many food plants such as the kernels of apricots, almonds and apples. 21 Amygdalin has been used as a main constituent in commercial preparations of laetrile, 22,23 a purported therapeutic agent. In particular, our aim is to synthesize amygdalin derivatives which can form nanoaggregates through self-assembly, encapsulation of hydrophobic drugs, followed by the release of the encapsulated drug upon enzyme mediated degradation (an enzyme triggered drug delivery model).…”

Section: Soft Materials From Amygdalin: Biocatalysis As a Tool To Mak...mentioning

confidence: 99%

Design and development of soft nanomaterials from biobased amphiphiles

John

Vemula

2006

Soft Matter

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Qualitative and Quantitative Analysis of Amygdalin Using NMR Spectroscopy

Cited by 16 publications

References 2 publications

Fungal endophytes of Vanilla planifolia across Réunion Island: isolation, distribution and biotransformation

Fungal endophytes of Vanilla planifolia across Réunion Island: isolation, distribution and biotransformation

In Situ Alkylation of Reconstructed Human Epidermis by Methyl Methanesulfonate: A Quantitative HRMAS NMR Chemical Reactivity Mapping

Design and development of soft nanomaterials from biobased amphiphiles

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