Simultaneous determination of caffeine, gallic acid, theanine, (−)-epigallocatechin and (−)-epigallocatechin-3-gallate in green tea using quantitative<sup>1</sup>H-NMR spectroscopy

Song, Yuelin; Jing, Wanghui; Wang, Ying; Yang, Xuejing; Liu, Deyun

doi:10.1039/c3ay41369a

Cited by 41 publications

(30 citation statements)

References 24 publications

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“…As a non-targeted method, NMR measurements do not require separation and chemical modification; therefore, comprehensive information regarding the chemical components of mixtures can be rapidly and directly provided [ 2 , 3 ]. For the past decade, NMR has been recognized as a powerful technique for discerning the chemical properties of complex mixtures and has been widely applied to identify organic compounds in foods, such as milk [ 4 ], soy sauce [ 5 ], coffee [ 6 ], wine [ 7 ], mango juice [ 8 ], and green tea [ 9 ]. Among NMR-based comprehensive analyses, 1 H NMR is the most useful tool because of its informative spectral patterns and high-throughput acquisition.…”

Section: Introductionmentioning

confidence: 99%

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Lü

Miyakawa

et al. 2016

Metabolites

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NMR measurements do not require separation and chemical modification of samples and therefore rapidly and directly provide non-targeted information on chemical components in complex mixtures. In this study, one-dimensional (1H, 13C, and 31P) and two-dimensional (1H-13C and 1H-31P) NMR spectroscopy were conducted to analyze yogurt without any pretreatment. 1H, 13C, and 31P NMR signals were assigned to 10 types of compounds. The signals of α/β-lactose and α/β-galactose were separately observed in the 1H NMR spectra. In addition, the signals from the acyl chains of milk fats were also successfully identified but overlapped with many other signals. Quantitative difference spectra were obtained by subtracting the diffusion ordered spectroscopy (DOSY) spectra from the quantitative 1H NMR spectra. This method allowed us to eliminate interference on the overlaps; therefore, the correct intensities of signals overlapped with those from the acyl chains of milk fat could be determined directly without separation. Moreover, the 1H-31P HMBC spectra revealed for the first time that N-acetyl-d-glucosamine-1-phosphate is contained in yogurt.

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Section: Introductionmentioning

confidence: 99%

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Lü

Miyakawa

et al. 2016

Metabolites

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“…Green tea is a well-studied mixture and its hot water extracts contain a number of NMR detectable compounds such as catechins, avonoids, caffeine, amino acids and carbohydrates. 24 Carbohydrates are the most abundant compound type producing crowded signals in the 1 H NMR spectra of green tea ( Fig. 2) and as such will be used here to illustrate the resolving power of the proposed experiments.…”

Section: Resultsmentioning

confidence: 99%

Reduced dimensionality hyphenated NMR experiments for the structure determination of compounds in mixtures

Sakas

Bell

2019

Faraday Discuss.

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“…S34-S36, respectively. The majority of the discriminating molecular formulae were assigned to the most likely compounds, considering those previously found in green tea [18][19][20]22,30,40,42,45,46 .…”

Section: Produced Only In Grassland (I 4 294) Only In Woodland (I mentioning

confidence: 99%

“…The spectra can be divided into three main regions: 8.5-6 ppm -aromatics (mostly catechins), caffeine (in the unburied tea); 5.5-3 ppm -mostly carbohydrates, caffeine, amino acids, catechins and organic acids; and 3-0 ppm, aliphatic molecules and moieties, such as amino acids, fatty acids and catechins. Assignment of the major signals present in the 1 H NMR spectrum of the HWE unburied tea based on literature data 22,29,30 and 2D NMR analysis 31 , is given in Supplementary Fig. S2.…”

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Molecular level study of hot water extracted green tea buried in soils - a proxy for labile soil organic matter

Bell

Smith

Zhu

et al. 2020

Sci Rep

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Understanding the composition of soil organic matter (SoM) is vital to our understanding of how soils form, evolve and respond to external stimuli. the shear complexity of SoM, an inseparable mixture of thousands of compounds hinders the determination of structure-function relationships required to explore these processes on a molecular level. Litter bags and soil hot water extracts (HWe) have frequently been used to study the transformation of labile SoM, however these are still too complex to examine beyond compound classes. in this work, a much simpler mixture, HWe buried green tea, was investigated by nuclear Magnetic Resonance (nMR) spectroscopy and fourier transform ion cyclotron Resonance Mass Spectrometry (ft-icR-MS), as a proxy for labile SoM. changes induced by the burial over 90 days in a grassland, woodland and two peatland sites, one damaged by drainage and one undergoing restoration by drain-blocking, were analysed. Major differences between the extracts were observed on the level of compound classes, molecular formulae and specific molecules. The causes of these differences are discussed with reference to abiotic and biotic processes. Despite the vastly different detection limits of NMR and MS, chemometric analysis of the data yielded identical separation of the samples. These findings provide a basis for the molecular level interrogation of labile SOM and c-cycling processes in soils. Earth's soils store a greater amount of C than both the vegetation and atmosphere combined and thus play a crucial role in the global C cycle 1. The accumulation of C is largely the result of restricted decomposition rates, which are ecosystem dependent. Three major causes for these restrictions include climate (temperature and moisture), substrate quality (chemical and physical characteristics), and the composition, abundance and activity of the soil biotia 2,3. Soil decomposition has historically been studied using litter bags, which consist of plant material of known mass enclosed in a screened container 4,5. A variety of different litter bag compositions and protocols have been used over the years, which makes a cross-study comparison practically impossible 6,7. More recently, a standardized method using green and rooibos Lipton tea bags has emerged 8 , which involves burying pairs of pre-weighed green and rooibos tea bags 15 cm apart to a depth of 8 cm. After 90 days, the tea bags are collected, dried and weighed. Using the fact that the rooibos tea decomposes slower than the green tea permits the so-called stabilization factor, S and decomposition rate, k, to be calculated from the determined weight losses. These two variables constitute the Tea Bag Index (TBI) which has been measured for different soils worldwide in order to define the relationships between soil types, decomposition rates and environmental factors 6,8-10. The tea bag decomposition rates, k, have been shown to positively correlate with those of local litter and respond in similar ways to biotic factors 7,9,11. On a molecular level soil litter d...

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Simultaneous determination of caffeine, gallic acid, theanine, (−)-epigallocatechin and (−)-epigallocatechin-3-gallate in green tea using quantitative¹H-NMR spectroscopy

Abstract: 1H-NMR spectroscopy is utilized for chemical characterization along with simultaneous determination of caffeine, gallic acid, theanine and tea polyphenols, in commercial green tea.

Cited by 41 publications

References 24 publications

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Reduced dimensionality hyphenated NMR experiments for the structure determination of compounds in mixtures

Molecular level study of hot water extracted green tea buried in soils - a proxy for labile soil organic matter

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Simultaneous determination of caffeine, gallic acid, theanine, (−)-epigallocatechin and (−)-epigallocatechin-3-gallate in green tea using quantitative1H-NMR spectroscopy

Abstract: 1H-NMR spectroscopy is utilized for chemical characterization along with simultaneous determination of caffeine, gallic acid, theanine and tea polyphenols, in commercial green tea.

Cited by 41 publications

References 24 publications

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Reduced dimensionality hyphenated NMR experiments for the structure determination of compounds in mixtures

Molecular level study of hot water extracted green tea buried in soils - a proxy for labile soil organic matter

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Product

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Simultaneous determination of caffeine, gallic acid, theanine, (−)-epigallocatechin and (−)-epigallocatechin-3-gallate in green tea using quantitative¹H-NMR spectroscopy