Dynamic Calibration Approach for Determining Catechins and Gallic Acid in Green Tea Using LC–ESI/MS

2011 ◽  
Vol 83 (16) ◽  
pp. 6169-6176 ◽  
Author(s):  
Mary Bedner ◽  
David L. Duewer
Keyword(s):  
Gallic Acid ◽  
Green Tea ◽  
Dynamic Calibration ◽  
Esi Ms ◽  
Calibration Approach

scholarly journals Aldose Reductase Differential Inhibitors in Green Tea

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1003 ◽  
Author(s):  
Francesco Balestri ◽  
Giulio Poli ◽  
Carlotta Pineschi ◽  
Roberta Moschini ◽  
Mario Cappiello ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Green Tea ◽  
Aldose Reductase ◽  
Active Site ◽  
Inhibitory Action ◽  
Computational Study ◽  
Epigallocatechin Gallate ◽  
Polyol Pathway ◽  
Differential Inhibition ◽  
Tea Extract

Aldose reductase (AKR1B1), the first enzyme in the polyol pathway, is likely involved in the onset of diabetic complications. Differential inhibition of AKR1B1 has been proposed to counteract the damaging effects linked to the activity of the enzyme while preserving its detoxifying ability. Here, we show that epigallocatechin gallate (EGCG), one of the most representative catechins present in green tea, acts as a differential inhibitor of human recombinant AKR1B1. A kinetic analysis of EGCG, and of its components, gallic acid (GA) and epigallocatechin (EGC) as inhibitors of the reduction of L-idose, 4-hydroxy2,3-nonenal (HNE), and 3-glutathionyl l-4-dihydroxynonanal (GSHNE) revealed for the compounds a different model of inhibition toward the different substrates. While EGCG preferentially inhibited L-idose and GSHNE reduction with respect to HNE, gallic acid, which was still active in inhibiting the reduction of the sugar, was less active in inhibiting HNE and GSHNE reduction. EGC was found to be less efficient as an inhibitor of AKR1B1 and devoid of any differential inhibitory action. A computational study defined different interactive modes for the three substrates on the AKR1B1 active site and suggested a rationale for the observed differential inhibition. A chromatographic fractionation of an alcoholic green tea extract revealed that, besides EGCG and GA, other components may exhibit the differential inhibition of AKR1B1.

Herbal infusions bioelectrochemical polyphenolic index: Green tea – The gallic acid interference

2011 ◽  
Vol 129 (4) ◽  
pp. 1537-1543 ◽  
Author(s):  
Dulce M.A. Gil ◽  
Pedro L.V. Falé ◽  
Maria L.M. Serralheiro ◽  
Maria J.F. Rebelo
Keyword(s):  
Gallic Acid ◽  
Green Tea ◽  
Herbal Infusions

scholarly journals Phenolic Antioxidants Identified by ESI-MS from Yerba Maté (Ilex paraguariensis) and Green Tea (Camelia sinensis) Extracts

Molecules ◽  
2007 ◽  
Vol 12 (3) ◽  
pp. 423-432 ◽  
Author(s):  
Deborah Bastos ◽  
Luciane Saldanha ◽  
Rodrigo Catharino ◽  
Alexandra Sawaya ◽  
Ildenize Cunha ◽  
...  
Keyword(s):  
Green Tea ◽  
Ilex Paraguariensis ◽  
Phenolic Antioxidants ◽  
Yerba Mate ◽  
Esi Ms

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

2014 ◽  
Vol 6 (3) ◽  
pp. 907-914 ◽  
Author(s):  
Yunfei Yuan ◽  
Yuelin Song ◽  
Wanghui Jing ◽  
Yitao Wang ◽  
Xiaoyun Yang ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Gallic Acid ◽  
Simultaneous Determination ◽  
Green Tea ◽  
Chemical Characterization ◽  
Tea Polyphenols ◽  
H Nmr

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

Quenching of α,β-unsaturated aldehydes by green tea polyphenols: HPLC–ESI–MS/MS studies

2008 ◽  
Vol 48 (3) ◽  
pp. 606-611 ◽  
Author(s):  
Giangiacomo Beretta ◽  
Sandra Furlanetto ◽  
Luca Regazzoni ◽  
Marina Zarrella ◽  
Roberto Maffei Facino
Keyword(s):  
Green Tea ◽  
Tea Polyphenols ◽  
Green Tea Polyphenols ◽  
Esi Ms ◽  
Unsaturated Aldehydes

Development of rapid and simultaneous quantitative method for green tea catechins on the bioanalytical study using UPLC/ESI-MS

2012 ◽  
Vol 27 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Shingen Misaka ◽  
Keisuke Kawabe ◽  
Satomi Onoue ◽  
José Pablo Werba ◽  
Monica Giroli ◽  
...  
Keyword(s):  
Green Tea ◽  
Quantitative Method ◽  
Tea Catechins ◽  
Esi Ms ◽  
Green Tea Catechins
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