Theaflavins in black tea and catechins in green tea are equally effective antioxidants

Lai Kwok Leung; Yalun Su; Ruoyun Chen; Zesheng Zhang; Yu Huang; Zhen-Yu Chen

doi:10.1093/jn/131.9.2248

Theaflavins in black tea and catechins in green tea are equally effective antioxidants

Lai Kwok Leung, Yalun Su, Ruoyun Chen, Zesheng Zhang, Yu Huang, Zhen-Yu Chen

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

465 Citations (Scopus)

Abstract

Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF₁), theaflavin-3-gallate (TF₂A), theaflavin-3′-gallate (TF₂B) and theaflavin-3,3′-digallate (TF₃). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu⁺²-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF₃ > ECG > EGCG ≥ TF₂B ≥ TF₂A > TF₁ ≥ EC > EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu⁺²-mediated LDL oxidation at concentrations of 5-40 μmol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.

Original language	English
Pages (from-to)	2248-2251
Journal	Journal of Nutrition
Volume	131
Issue number	9
DOIs	https://doi.org/10.1093/jn/131.9.2248
Publication status	Published - 2001
Externally published	Yes

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Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

Research Keywords

Black tea
Catechins
Green tea
Low density lipoprotein
Oxidation
Theaflavins

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title = "Theaflavins in black tea and catechins in green tea are equally effective antioxidants",

abstract = "Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3′-gallate (TF2B) and theaflavin-3,3′-digallate (TF3). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu+2-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF3 > ECG > EGCG ≥ TF2B ≥ TF2A > TF1 ≥ EC > EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu+2-mediated LDL oxidation at concentrations of 5-40 μmol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.",

keywords = "Black tea, Catechins, Green tea, Low density lipoprotein, Oxidation, Theaflavins",

author = "Leung, {Lai Kwok} and Yalun Su and Ruoyun Chen and Zesheng Zhang and Yu Huang and Zhen-Yu Chen",

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T1 - Theaflavins in black tea and catechins in green tea are equally effective antioxidants

AU - Leung, Lai Kwok

AU - Su, Yalun

AU - Chen, Ruoyun

AU - Zhang, Zesheng

AU - Huang, Yu

AU - Chen, Zhen-Yu

N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

PY - 2001

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N2 - Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3′-gallate (TF2B) and theaflavin-3,3′-digallate (TF3). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu+2-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF3 > ECG > EGCG ≥ TF2B ≥ TF2A > TF1 ≥ EC > EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu+2-mediated LDL oxidation at concentrations of 5-40 μmol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.

AB - Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3′-gallate (TF2B) and theaflavin-3,3′-digallate (TF3). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu+2-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF3 > ECG > EGCG ≥ TF2B ≥ TF2A > TF1 ≥ EC > EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu+2-mediated LDL oxidation at concentrations of 5-40 μmol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.

KW - Black tea

KW - Catechins

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KW - Low density lipoprotein

KW - Oxidation

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DO - 10.1093/jn/131.9.2248

M3 - RGC 21 - Publication in refereed journal

C2 - 11533262

SN - 0022-3166

VL - 131

SP - 2248

EP - 2251

JO - Journal of Nutrition

JF - Journal of Nutrition

IS - 9

ER -

Theaflavins in black tea and catechins in green tea are equally effective antioxidants

Abstract

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