An LC-ESI/MS method for determining theanine in green tea dietary supplements

Bedner, Mary; Sander, Lane C.; Sharpless, Katherine E.

doi:10.1007/s00216-010-3713-9

Cited by 14 publications

(8 citation statements)

References 13 publications

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“…It is abundant in all protein foods, while its richest sources are fish and wheat bran [9]. It is derived from L-glutamate, a breakdown product of L-theanine [10,11]; the two reactions involved are catalyzed consecutively by theanine hydrolase (TH, EC 3.5.1.65) and a cytosolic glutamic acid decarboxylase (GAD, EC 4.1.1.15). GABA can be further metabolized by two mitochondrial enzymes, GABA transaminase (GABA-T, EC 2.6.1.19) and succinic semialdehyde dehydrogenase (SSADH, EC 1.2.1.24), to succinate semi aldehyde and succinate, respectively [10].…”

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confidence: 99%

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Quantification of γ-Aminobutyric Acid in Sri Lankan Tea by Means of Ultra Performance Tandem Mass Spectrometry

Carvalho

Punyasiri

Somasiri

et al. 2014

Natural Product Communications

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γ-Aminobutyric acid (GABA), an important bioactive component of tea, acts as a major inhibitory neurotransmitter and is considered to influence other physiological processes in human as well as in planta. In the hereby presented study, the content of this valuable metabolite was investigated in two novel types of Ceylon Tea, explicitly "Silver Tips" and "White Tea", originating from minimally processed buds of the unique cultivar, "TRI 2043". The samples were subjected to hot water infusion, equivalent to the traditional beverage preparation procedure, and analyzed by means of hydrophilic interaction ultra performance liquid chromatography coupled to tandem mass spectrometry (HILIC LC-MS/MS). The registered GABA levels were compared with those obtained for the classic "Black Tea" and "Green Tea" samples from Sri Lanka. A high variation of GABA content was observed among the different tea types, especially in the case of "Silver Tips" and "White Tea", indicating the crucial influence of the manufacturing procedure (processing extent) on the final abundance of the bioactive component of interest. Furthermore, "White Tea" samples boasted the highest GABA concentration reported for this type of tea so far, reaching up to 50% of that characteristic of the high-priced "GABA Tea". Therefore, "White Tea" and "Silver Tips" were proved to be high quality teas with amounts of γ-aminobutyric acid comparable with those described for similar types before. To our knowledge, this is the first report on HILIC LC-MS/MS application for the quantification of GABA and for in-depth characterization of teas from Sri Lanka.

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Quantification of γ-Aminobutyric Acid in Sri Lankan Tea by Means of Ultra Performance Tandem Mass Spectrometry

Carvalho

Punyasiri

Somasiri

et al. 2014

Natural Product Communications

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“…of Standards and Technology (NIST) now offers a suite of green tea reference materials and a catechin calibration solution developed to evaluate the chemical composition of green tea dietary supplement products. These Standard Reference Materials® (SRMs), SRM 3254, SRM 3255, SRM 3256, and SRM 3257 are available on the NIST Website (http://www.nist.gov/srm/index.cfm) (Bedner and others , ; Sander and others ). The Certificates of Analysis that accompany the SRMs provide assigned values for concentrations of 7 catechins and gallic acid, 3 xanthine alkaloids (including caffeine), theanine, and toxic elements (arsenic, cadmium, lead, and mercury).…”

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confidence: 99%

Feasibility of Including Green Tea Products for an Analytically Verified Dietary Supplement Database

Saldanha

Dwyer

Andrews

et al. 2015

Journal of Food Science

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The Dietary Supplement Ingredient Database (DSID) is a federally funded, publicly accessible dietary supplement database that currently contains analytically-derived information on micronutrients in selected adult and children’s multivitamin and mineral (MVM) supplements. Other constituents in dietary supplement products such as botanicals are also of interest and thus are being considered for inclusion in the DSID. Thirty-eight constituents, mainly botanicals were identified and prioritized by a federal interagency committee. Green tea was selected from this list as the botanical for expansion of the DSID. This paper describes the process for prioritizing dietary ingredients in the DSID. It also discusses the criteria for inclusion of these ingredients, and the approach for selecting and testing products for the green tea pilot study.

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“…The most significant challenges were related to the determination of low-level catechins, fully resolving closely related compounds, and detection of theanine (which has no chromophore). As with the multivitamin, the development of state-of-the art separation methods for the catechins (31,32) and the development of an ID-LC-MS method for the detection of theanine (33) were essential for the measurement community. In addition, the development of linked, authenticated materials for the leaves and the extracts allows for laboratories to develop and test identification and authentication methods.…”

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Challenges in Developing Analytically Validated Laboratory-Derived Dietary Supplement Databases

Betz

Rimmer

Saldanha

et al. 2018

The Journal of Nutrition

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The Dietary Supplement Label Database (DSLD) is sponsored by the Office of Dietary Supplements (ODS) and the National Library of Medicine (NLM). It provides a searchable, free database of the contents of ∼65,000 supplement labels. A companion database of analytically verified product labels [the Dietary Supplement Ingredient Database (DSID)] was created by ODS, NLM, and the USDA. There are considerable challenges to populating both databases, but the DSID faces unique analytic chemistry challenges. This article describes the challenges to creating analytically verified marketplace surveys of dietary supplement (DS) product content claims for inclusion in public databases. Nutritionists and public health scientists require information on actual exposures to DS constituents because labeled content may not match labeled product content. Analytic verification of composition of DSs provides a link to actual exposure. A public database of analytically derived DS content was developed to provide more accurate estimates of dietary intake in population-based epidemiologic studies. The DSID has conducted surveys of several types of vitamin- and mineral-containing DSs. Results showing label content claims as analytically derived values are available in the current DSID. A recent pilot project explored the feasibility of adding botanical DS products to the DSID. Candidates for future botanical DSID studies will be based on sales volume, potential public health impacts, and the availability of validated analytic methods and reference materials. Databases like DSID and the DSLD are essential for researchers and clinicians to evaluate dietary ingredient intakes in population-based epidemiologic studies. Together, these databases provide a picture of the DS marketplace. The DSID provides an analytic survey of marketed DSs. However, selection of future botanical supplements for DSID evaluation involves analytic challenges. Even when appropriate resources are available, method selection and data evaluation are resource- and time-consuming.

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An LC-ESI/MS method for determining theanine in green tea dietary supplements

Cited by 14 publications

References 13 publications

Quantification of γ-Aminobutyric Acid in Sri Lankan Tea by Means of Ultra Performance Tandem Mass Spectrometry

Quantification of γ-Aminobutyric Acid in Sri Lankan Tea by Means of Ultra Performance Tandem Mass Spectrometry

Feasibility of Including Green Tea Products for an Analytically Verified Dietary Supplement Database

Challenges in Developing Analytically Validated Laboratory-Derived Dietary Supplement Databases

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