MHz 1H NMR Spectroscopy Research Articles

Association Between Changes in Serum and Skeletal Muscle Metabolomics Profile With Maximum Power Output Gains in Response to Different Aerobic Training Programs: The Times Study.

Purpose: High heterogeneity of the response of cardiorespiratory fitness (CRF) to standardized exercise doses has been reported in different training programs, but the associated mechanisms are not widely known. This study investigated whether changes in the metabolic profile and pathways in blood serum and the skeletal muscle are associated with the inter-individual variability of CRF responses to 8-wk of continuous endurance training (ET) or high-intensity interval training (HIIT).Methods: Eighty men, young and sedentary, were randomized into three groups, of which 70 completed 8 wk of intervention (> 90% of sessions): ET, HIIT, or control. Blood and vastus lateralis muscle tissue samples, as well as the measurement of CRF [maximal power output (MPO)] were obtained before and after the intervention. Blood serum and skeletal muscle samples were analyzed by 600 MHz 1H-NMR spectroscopy (metabolomics). Associations between the pretraining to post-training changes in the metabolic profile and MPO gains were explored via three analytical approaches: (1) correlation between pretraining to post-training changes in metabolites' concentration levels and MPO gains; (2) significant differences between low and high MPO responders; and (3) metabolite contribution to significantly altered pathways related to MPO gains. After, metabolites within these three levels of evidence were analyzed by multiple stepwise linear regression. The significance level was set at 1%.Results: The metabolomics profile panel yielded 43 serum and 70 muscle metabolites. From the metabolites within the three levels of evidence (15 serum and 4 muscle metabolites for ET; 5 serum and 1 muscle metabolites for HIIT), the variance in MPO gains was explained: 77.4% by the intervention effects, 6.9, 2.3, 3.2, and 2.2% by changes in skeletal muscle pyruvate and valine, serum glutamine and creatine phosphate, respectively, in ET; and 80.9% by the intervention effects; 7.2, 2.2, and 1.2% by changes in skeletal muscle glycolate, serum creatine and creatine phosphate, respectively, in HIIT. The most changed and impacted pathways by these metabolites were: arginine and proline metabolism, glycine, serine and threonine metabolism, and glyoxylate and dicarboxylate metabolism for both ET and HIIT programs; and additional alanine, aspartate and glutamate metabolism, arginine biosynthesis, glycolysis/gluconeogenesis, and pyruvate metabolism for ET.Conclusion: These results suggest that regulating the metabolism of amino acids and carbohydrates may be a potential mechanism for understanding the inter-individual variability of CRF in responses to ET and HIIT programs.

Mitigating instrument effects in 60 MHz 1H NMR spectroscopy for authenticity screening of edible oils

Low field (60 MHz) 1H NMR spectroscopy was used to analyse a large (n = 410) collection of edible oils, including olive and argan, in an authenticity screening scenario. Experimental work was carried out on multiple spectrometers at two different laboratories, aiming to explore multivariate model stability and transfer between instruments. Three modelling methods were employed: Partial Least Squares Discriminant Analysis, Random Forests, and a One Class Classification approach. Clear inter-instrument differences were observed between replicated data collections, sufficient to compromise effective transfer of models based on raw data between instruments. As mitigations to this issue, various data pre-treatments were investigated: Piecewise Direct Standardisation, Standard Normal Variates, and Rank Transformation. Datasets comprised both phase corrected and magnitude spectra, and it was found that that the latter spectral form may offer some advantages in the context of pattern recognition and classification modelling, particularly when used in combination with the Rank Transformation pre-treatment.

A ceric ammonium nitrate based oxidative cleavage pathway for the asymmetric aldol adducts of oxadiazinones derived from (1R,2S)-N-p-methoxybenzylnorephedrine

An N4-p-methoxybenzyloxadiazinone has been prepared from (1R,2S)-norephedrine through a process of reductive amination, N-nitrosation, reduction, and cyclization. The oxadiazinone was acylated and employed in the asymmetric aldol addition reaction with aromatic and aliphatic aldehydes to yield aldol adducts in isolated yields ranging from 54% to 90%. Selected aldol adducts were treated with ceric ammonium nitrate in aqueous acetonitrile to afford the desired β-hydroxycarboxylic acids through a tandem process of oxidative cleavage of the N4-p-methoxybenzyl group and acidic hydrolysis of the N3-acyl side chain. The β-hydroxycarboxylic acids were recovered in high diastereomeric purity as determined by 500MHz 1H NMR spectroscopy and the absolute configuration was confirmed by polarimetry. The chiral auxiliary unit, the 3,4,5,6-tetrahydro-2H-1,3,4-oxadiazin-2-one (oxadiazinone), was converted into its corresponding 3,6-dihydro-2H-1,3,4-oxadiazin-2-one (oxadiazinone) through an oxidative pathway promoted by the ceric ammonium nitrate.

Synthesis of multivalent carbohydrate mimetics with aminopolyol end groups and their evaluation as L-selectin inhibitors.

In this article a series of divalent and trivalent carbohydrate mimetics on the basis of an enantiopure aminopyran and of serinol is described. These aminopolyols are connected by amide bonds to carboxylic acid derived spacer units either by Schotten–Baumann acylation or by coupling employing HATU as reagent. The O-sulfation employing the SO3·DMF complex was optimized. It was crucial to follow this process by 700 MHz 1H NMR spectroscopy to ensure full conversion and to use a refined neutralization and purification protocol. Many of the compounds could not be tested as L-selectin inhibitor by SPR due to their insolubility in water, nevertheless, a divalent and a trivalent amide showed surprisingly good activities with IC50 values in the low micromolar range.

1,6‐ and 1,7‐Regioisomers of Dicyano‐Substituted Perylene Bisimides: Synthesis, Optical and Electrochemical Properties

AbstractIn this study, 1,6‐ ad 1,7‐regioisomers of dicyano‐substituted perylene bisimides (1,6‐C and 1,7‐C) were synthesized and successfully isolated from their regioisomeric mixture using conventional methods of separation, and subsequently characterized by 400 MHz 1H NMR spectroscopy. This is the first time that the 1,6‐dicyanoperylene bisimide 1,6‐C has been obtained in pure form. Moreover, the optical and electrochemical properties of 1,6‐C and 1,7‐C were found to be virtually the same. Time‐dependent density functional theory calculations performed on both dyes are reported in order to rationalize their electronic structures and optical properties.

Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy

This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60MHz 1H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional “authentic” beef region (p=0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze–thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60MHz 1H NMR represents a feasible high-throughput approach for screening raw meat.

1,6‐Dinitroperylene Bisimide Dyes: Synthesis, Characterization and Photophysical Properties

Abstract1,6‐ and 1,7‐regioisomers of dinitro‐substituted perylene bisimides (1a—1b and 2a—2b) were synthesized under mild condition in high yields. The 1,6‐ and 1,7‐regioisomers were successfully isolated from the regioisomeric mixture using conventional methods of separation and subsequently characterized by 500 MHz 1H NMR spectroscopy. This is the first time when 1,6‐dinitroperylene bisimides (1a—1b) are obtained in pure form. Furthermore, the photophysical and electrochemical properties of 1 and 2 were found to be almost the same. The nitro functionalities provide stability of n‐type charge carriers by lowering the LUMO to resist ambient oxidation, which may offer potential applications in air‐stable n‐type organic semiconductors.

1,6- and 1,7-Regioisomers of Asymmetric and Symmetric Perylene Bisimides: Synthesis, Characterization and Optical Properties

The 1,6- and 1,7-regioisomers of dinitro- (1,6-A and 1,7-A) and diamino-substituted perylene bisimides (1,6-B and 1,7-B), and 1-amino-6-nitro- and 1-amino-7-nitroperylene bisimides (1,6-C and 1,7-C) were synthesized. The 1,6-A and 1,7-A regioisomers were successfully separated by high performance liquid chromatography and characterized by 500 MHz 1H-NMR spectroscopy, and subsequently, their reduction which afforded the corresponding diaminoperylene bisimides 1,6-B and 1,7-B, respectively. On the other hand, the monoreduction of 1,6-A and 1,7-A, giving the asymmetric 1-amino-6-nitro (1,6-C) and 1-amino-7-nitroperylene bisimides (1,7-C), respectively, can be performed by shortening the reaction time from 6 h to 1 h. This is the first time the asymmetric 1,6-disubstituted perylene bisimide 1,6-C is obtained in pure form. The photophysical properties of 1,6-A and 1,7-A were found to be almost the same. However, the regioisomers 1,6-C and 1,7-C, as well as 1,6-B and 1,7-B, exhibit significant differences in their optical characteristics. Time-dependent density functional theory calculations performed on these dyes are reported in order to rationalize their electronic structure and absorption spectra.

1,6- and 1,7-regioisomers of dinitro- and diamino-substituted perylene bisimides: synthesis, photophysical and electrochemical properties

1,6- and 1,7-regioisomers of dinitro- (1,6-3 and 1,7-3) and diamino-substituted perylene bisimides (1,6-1 and 1,7-1) were synthesized. The regioisomers 1,6-3 and 1,7-3 were successfully separated by high performance liquid chromatography and characterized by 500MHz 1H NMR spectroscopy. Subsequently, the reduction of 1,6-3 and 1,7-3 afforded the corresponding diaminoperylene bisimides 1,6-1 and 1,7-1, respectively. This is the first time 1,6-regioisomers of dinitro- and diamino-substituted perylene bisimides are obtained in pure form. The photophysical and electrochemical properties of 1,6-3 and 1,7-3 were found to be almost the same. However, the regioisomers 1,6-1 and 1,7-1 exhibit significant differences in their optical characteristics. The absorption spectrum of 1,6-1 covers a larger part of the visible region compared to that of 1,7-1. Upon excitation, 1,6-1 also show larger dipole moment change than that of 1,7-1. Time-dependent density functional theory calculations are reported on these dyes in order to rationalize their electronic structure and absorption spectra.

An NMR Metabolomics Investigation of Perturbations after Treatment with Chinese Herbal Medicine Formula in an Experimental Model of Sepsis

Sepsis is a leading cause of morbidity and mortality in critically ill patients. OMICS and systems pharmacology approaches offer the promise of new therapeutic candidates for the treatment of patients with sepsis. Qin-Re-Jie-Du (QRJD) and Liang-Xue-Huo-Xue (LXHX) are two traditional Chinese herbal medicine (CHM) formulas with putative effects in sepsis treatment. The present study aimed to assess their efficacy in an experimental model of sepsis in rats (cecal ligation and punctures) and investigate their mechanism of action using a 1H-NMR metabolomics approach. Rats were randomly divided into four groups (i.e., model group, sham control group, and two CHM treatment groups). Water extracts of QRJD and LXHX were orally administered to the two CHM treatment groups at a dose of 24 g/kg of body weight, once daily for 3 consecutive days. The same volume of 0.9% saline solution was orally administered to the model and sham surgery groups. Plasma samples were collected and measured using 600 MHz 1H-NMR spectroscopy. As a result, 18 potential metabolite biomarkers involved in multiple metabolic pathways, including increased energy metabolism, fat mobilization, and disrupted amino acid metabolism, were identified in septic rats. The principal component analysis (PCA) and partial least squares discriminant (PLS-DA) plots of the metabolic state correlated well with the mortality and clinical biochemistry results. An analysis of potential biomarkers verified the holistic effects of the two CHM formulas. The Cori cycle was positively regulated in the QRJD-treated formulas treatment group but also inhibited in the LXHX-treated group, which demonstrates the different efficacies of these solutions in septic rats.

Abstract B14: Predicting prostate cancer: a novel, non-invasive approach

Abstract Introduction: Current approaches to the detection of prostate cancer require improvement. PSA and other methods fall short in discriminating between benign and malignant prostates, as well as defining the nature of disease. We hypothesize that multiple markers, in non-invasive samples, can better detect prostate cancer and improve patient outcomes. Methods: Discriminating mRNA markers in prostatic tissues were identified, and quantified using standard assays, to complement the non-coding gene PCA3. Complementary metabolomic analysis of ejaculate was performed using 500 MHz 1H-NMR spectroscopy. Results: In 100 patients, RT-PCR for PCA3 and Hepsin from ejaculate in combination with serum PSA provided improved prediction compared with PSA alone. Further mRNA markers marginally improved these results. Metabolomic analysis of ejaculate was initially confounded by contributions from buffer solution. Appropriate exclusion of confounders provided improved insight into sample and disease pathophysiology, and was combined with the molecular analysis. Preliminary results have indicated that combining molecular and metabolomic data promise to improve detection rates. Results from this combined data analysis will be presented. Furthermore, patients with initially negative prostate biopsies have been monitored for disease progression, with a number changing status over time. These findings have been analyzed and will also be presented. Conclusion: Our results suggest that there is potential for non-invasive detection of prostate cancer. Current methods of detection are improved by combining clinical, genetic and metabolic markers from excreted biofluids. Further insight is provided into the pathophysiology of prostate cancer, which will further advance integration with imaging, as well as advancing the development of an accurate, non-invasive screening test for prostate cancer. Citation Format: Matthew J. Roberts, Horst J. Schirra, Martin F. Lavin, Robert A. Gardiner. Predicting prostate cancer: A novel, noninvasive approach. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr B14.

1,7- And 1,6-Regioisomers of Diphenoxy and Dipyrrolidinyl Substituted Perylene Diimides: Synthesis, Separation, Characterization, and Comparison of Electrochemical and Optical Properties

1,7- And 1,6-regioisomers of N,N′-dioctyl-di(2,4-di-tert-butylphenoxy)perylene diimide (1,7-5 and 1,6-5) and N,N′-dioctyl-dipyrrolidinylperylene diimide (1,7-8 and 1,6-8) dyes are prepared. These 1,7- and 1,6-regioisomers are successfully isolated from the regioisomeric mixture using conventional methods of separation and subsequently characterized, unambiguously, by 300 MHz 1H NMR spectroscopy. This is the very first time when 1,6-regioisomers of diphenoxy and dipyrrolidinyl substituted perylene diimides are obtained in pure form. Optical and redox properties of these 1,6-regioisomers are examined extensively and compared with respective 1,7-regioiosmers. The optical and electrochemical characteristics of diphenoxy substituted isomers, 1,7-5 and 1,6-5, were found to be virtually the same. However, quite unexpectedly, crucial differences were observed in the properties of regioisomers of dipyrrolidinyl substituted PDIs, 1,7-8 and 1,6-8. Differential pulse voltammetry revealed that 1,7-8 has better electro...

ChemInform Abstract: Highly Diastereoselective Reduction of Ketones in 2-Acyl-2-alkyl-1,3- dithiane 1-Oxides.

2-Acyl-2-alkyl-1,3-dithiane 1-oxides undergo diastereoselective reduction upon treatment with diisobutylaluminium hydride to give the corresponding secondary alcohols. The sense of diastereoselectivity is commonly reversed by the presence of zinc chloride during the action of the reducing agent. In many cases diastereoselectivity is sufficiently high that the minor isomer could not be detected by 400 MHz 1H NMR spectroscopy.

Bond reactivity and antioxidant effect on the autoxidation of soybean oil

Soybean oil (SBO) contains many unsaturated fatty acids, so that it can be easily oxidized by air/oxygen. Therefore the autoxidation of soybean oil was performed to investigate the bond reactivities of allylic, bisallylic CH 2, α-CH 2, β-CH 2, chain CH 2 and CH 2O of backbone in the presence and absence of phenolic and aniline antioxidants by means of iodometry and 500 MHz 1H NMR spectroscopy. From the active oxygen concentration, the inhibiting effect and by application of proton integration of each bond of pure and oxidized soybean oil to the first order rate equation, got firstly the orders of the reactivity of each C–H bond and inhibiting effect of antioxidants. In the presence of 2,6-di- t-butyl-4-cresol, three phenol adducts from oxidation product also firstly were identified by means of GC–MS spectroscopy.

The Lan3‐2 glycoepitope of Hirudo medicinalis consists of β‐(1,4)‐linked mannopyranose

While glycosyltransferases are restrictively expressed in invertebrate model organisms, little is known of their glycan end products. One such restrictively expressed glycoepitope was localized to sensory and epithelial cells of leech and Caenorhabditis elegans using the Lan3-2 monoclonal antibody. A biological function for the neural Lan3-2 epitope was previously determined in the leech. Here we report on the chemical structure of this mannosidic epitope harvested from whole Hirudo medicinalis. Crude glycans were liberated from glycoproteins by hydrazinolysis. Re-N-acetylated glycans were subjected to immunoaffinity purification. The affinity-purified glycans were fractioned by size chromatography into oligosaccharides and polysaccharides. Lan3-2 oligosaccharide structure was characterized by gas chromatography of alditol acetates, methylation analysis, 500 MHz 1H NMR spectroscopy, matrix-assisted laser desorption/ionization mass spectrometry, and electrospray ionization tandem MS-MS of permethylated derivatives. The predominant components of the Lan3-2 oligosaccharide fraction were a series of linear beta-(1,4)-linked mannose polymers. The homologous expression of the Lan3-2 epitope in C. elegans will facilitate the exploration of its glycosylation pathway. Other invertebrates expressing the Lan3-2 epitope are Planaria dugesia, Capitella sp. I and Lumbriculus variegatus. The glycoepitope was not detected in the diploblastic animals Hydra littoralis and Aptaisia sp. or in deuterostomes.

Comparative Study on the Conformation of Phalloidin, Viroisin, and Related Derivatives in Aqueous Solution

We investigated the conformations of toxic phalloidin and viroisin in aqueous solution using 500–MHz 1H-NMR spectroscopy in conjunction with molecular modeling. The conformations of two non-toxic phalloidin derivatives, secophalloidin and dethiophalloidin, were also correspondingly studied for comparison purposes. Results indicate that the non-toxic peptides have a multiple conformation, whereas the toxic peptides are comprised of a rigid molecule. It was found that the conformation of phalloidin partially resembles that of viroisin in the region of Cys3-Pro4-Ala5-Trp6, being different from that of the non-toxic peptides; thereby suggesting this region plays an important role leading to their toxicity.

Larvicidal Properties of the Three Major Furostanol Saponins of Balanites aegyptiaca Fruit Mesocarp against Aedes agypti Mosquito Larvae

Among various biological activities, saponin-rich extracts have been found to be larvicidal against mosquito larvae; however, no study so far has reported using pure furostanol saponins. In this study, three major furostanol saponins: 26-( O-β-D-glucopyranosyl)-3β,22,26-trihydroxyfurost-5-ene 3- O-β-D-glucopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (1), 26-( O-β-D-glucopyranosyl)-22- O-methylfurost-5-ene-3β,26-diol 3- O-β-D-xylopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (2), and 26-( O-β-D-glucopyranosyl)-22- O-methylfurost-5-ene.3β,26-diol 3- O-β-D-glucopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (3) were isolated from methanol extracts of the fruit mesocarp of Balanites aegyptiaca (L.) Del. (desert date). Their identification was carried out by ESI-MSn and structures were elucidated by 800 MHz 1H NMR spectroscopy. The larvicidal properties of these saponins against the Aedes aegypti mosquito larvae were evaluated. Results suggest that all three saponins possess larvicidal activity, but the activity was found to be related to the structure of the saponins, basically in the C-22 position of the aglycone and in the oligosaccharide chain. A furostanol saponin that presents -OCH3 at the C-22 position compared to an -OH group, and the lack of a xylose molecule compared to its presence is found to be more larvicidal.

Metabonomic Studies on the Physiological Effects of Acute and Chronic Psychological Stress in Sprague−Dawley Rats

The biochemical effects of acute and chronic psychological stress have been investigated in male Sprague-Dawley rats using a combination of 1H NMR spectral analysis of plasma and conventional hematological analyses. Animals were subjected to 35 consecutive days of 6-h sessions of stress, and following a 9 day break, were stressed for a further 6-h period. Plasma samples were collected at 0, 1, 3, and 6 h on days 1, 9, 21, 35, and 44, measured using 600 MHz 1H NMR spectroscopy, and analyzed by Principal Components Analysis. Time-dependent biochemical effects of psychological stress on a range of endogenous metabolites were evident and were correlated with the intensity of the stress response as defined by corticosterone and hematological parameters. Following acute stress, increases in the levels of glucose and ketone bodies, and decreases in the levels of acetate, alanine, isoleucine, lactate, leucine, valine, and lipoproteins, were observed. Chronic stress-induced increases in plasma levels of alanine, lactate (day 9), and leucine, valine, and choline (day 44) and decreases in acetate (day 9) and lipoprotein concentrations were observed. Positive correlations between plasma corticosterone level and glucose and glycerol, and between plasma lipoprotein concentrations and hemoglobin levels, were established using Projection to Latent Structures (PLS) analysis. This study indicates the potential of using NMR-based metabonomic strategies for the characterization of endogenous metabolic perturbations induced by psychological stressors and lifestyle choices.

Investigation of the complexation of the anti-cancer drug novantrone with the hairpin structure of the deoxyheptanucleotide 5′-d(GpCpGpApApGpC)

In aqueous solution the deoxyheptanucleotide, 5′-d(GpCpGpApApGpC), exists as a very stable hairpin structure in equilibrium with small proportions of the single-stranded and duplex forms. Complexation of the anti-cancer drug novantrone (mitoxantrone) with the DNA heptamer was investigated by one- and two-dimensional 500 MHz 1H NMR spectroscopy (2M-TOCSY, 2M-NOESY) and molecular dynamics simulations. The proton chemical shifts of NOV in mixed solutions with the heptamer were measured as a function of concentration and temperature and the equilibrium association parameters were determined for complexation of NOV with the three forms of the heptamer. The spatial structure of the complex of the antibiotic with the hairpin form of the heptamer was built on the basis of 2D-NOE data. The conformational dynamics of the complex and its interaction with the water environment were investigated by molecular dynamics methods. The results suggest that NOV complexes with the hairpin form of the heptamer in solution by intercalation. Complexation of NOV with the hairpin stem results in a disruption of about one half of the intramolecular water bridges of the hairpin, which is considered to be the main reason for the observed decrease in the thermodynamical stability of the hairpin on binding with the ligand.

Complexation of anthracycline drugs with DNA in the presence of caffeine

The competitive binding of anthracycline antitumour drugs, [daunomycin (DAU), doxorubicin (DOX) or nogalamycin (NOG)], with caffeine (CAF) to a model DNA oligomer has been investigated by 500 MHz 1H NMR spectroscopy under physiological solution conditions. The method depends on the stepwise analysis of one-component (self-association), two-component (hetero-association and DNA complexation) and three-component interactions, in order to de-convolute the overall binding of the anthracycline antibiotic and CAF to DNA into two competing processes, viz. hetero-association of the antibiotic-CAF ('interceptor' action of CAF) and CAF-DNA complexation ('protector' action of CAF). It is found that the complexation of DAU with DNA in the presence of CAF is mainly affected by the CAF-DNA complexation, whereas the binding of either DOX or NOG to DNA is affected approximately equally by both the CAF-DNA complexation and CAF-antibiotic hetero-association. Quantitative evaluation of the three-component mixture of drug-CAF-DNA has enabled the proportion of the antibiotic displaced from DNA on addition of CAF to be calculated over a large range of CAF concentration, which may provide a quantitative basis for the change in anthracycline-related toxicity on addition of CAF.