Chemiluminescence–High-Performance Liquid Chromatographic Determination of Tea Catechin, (−)-Epigallocatechin 3-Gallate, at Picomole Levels in Rat and Human Plasma

Nakagawa, Kiyotaka; Miyazawa, Teruo

doi:10.1006/abio.1997.2098

Cited by 169 publications

(108 citation statements)

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“…The detection limit for PY was 2.5-fold lower than that obtained by the FIA-electrochemistry chemiluminescence method; 19 the detection limit of GA was 5-fold higher than that obtained by the GC/MS method; 10 EGC and EGCG showed the same sensitivity as with the HPLC-CL method. 20,21 In the HPLC-CL assay, H2O2/CH3CHO/HRP was used. Polyphenol reacts with H2O2 to form an oxygenated intermediate, which is then converted to an electrically excited hydroxyl compound under the oxygenation of acetaldehyde.…”

Section: Resultsmentioning

confidence: 99%

Determination of Polyphenols with HPLC-Sensitized Chemiluminescence

Nakazono

Ohba

et al. 2002

ANAL. SCI.

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Section: Resultsmentioning

confidence: 99%

Determination of Polyphenols with HPLC-Sensitized Chemiluminescence

Nakazono

Ohba

et al. 2002

ANAL. SCI.

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“…Generally, tea catechins are analyzed using high-performance liquid chromatography (HPLC) with ultraviolet (UV), chemiluminescence (CL), or electrochemical detection (ECD) also commonly used are capillary electrophoresis (CE) and gas chromatography with mass spectrometry (GC-MS) [14][15][16][17][18]. These methods have been used for determining catechin concentrations in tea, rat plasma, human plasma, and urine.…”

Section: Methods Of Analysis For Green Tea Catechinsmentioning

confidence: 99%

Green Tea Catechins -Pharmacokinetic Properties and Health Beneficial Effects

ErisaTomishige¹

2015

Pharm Anal Acta

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In this review, we provide information on thepharmacokinetic properties of green tea catechins and their beneficial health effects. The major catechins in green tea are (-)-epicatechin (EC), its hydroxyl derivative (-)-epigallocatechin (EGC), and their gallic acid esters, (-)-epicatechin-3-gallate (ECg) and (-)-epigallocatechin-3-gallate (EGCg). We developed an analytical method for determination of the presence of green tea catechins in human serum using ion-pair HPLC with electrochemical detection to estimate the pharmacokinetic parameters of target catechins. The C max values indicated that catechin absorption was relatively low. One of the gallatedcatechins, EGCg, had a longer half-life than the non-gallatedcatechins. Green tea catechins, in particular, have attracted attention as cancer preventive agents in terms of their low toxicity and being readily available to the general population. Several epidemiological studies revealed that green tea consumption reduces cancer incidence. Numerous in vitro cell culture studies have shown that EGCg, which is defined as a major green tea catechin contributing to green tea's anticancer effects, inhibits cell growth concomitant with induction of apoptosis. We have previously found that the cell death-inhibiting gene, Bcl-xL, was decreased by EGCg. These results support the hypothesis that EGCg regulates cytoplasmic NF-κB and subsequently induction of apoptosis. Green tea consumption may also play a role in preventing other lifestyle diseases, such as cardiovascular diseases and stroke, due to its hypocholesterolemic and hypotensive activities. In conclusion, habitual green tea drinking may promote human health by preventing lifestyle-related diseases.

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“…Despite the excellent properties of tea catechins, they have at least one limitation, their low bioavailability (Nakagawa & Miyazawa, 1997). Factors influencing this low bioavailability could be related to their low stability in neutral or slightly alkaline solutions and their inability to cross cellular membranes (Hong et al, 2002).…”

Section: Synthetic Catechins As Antifolate Prodrugs Against Melanomamentioning

confidence: 99%