Preparation of Epimers of Tea Catechins by Heat Treatment

Seto, Ryota; Nakamura, Hironori; Nanjo, Fumio; Hara, Yukihiko

doi:10.1271/bbb.61.1434

Cited by 185 publications

(153 citation statements)

References 10 publications

(10 reference statements)

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“…And their isomers, (+)-epicatechin (+EC), (−)-catechin (−C), (−)-gallocatechin (−GC), (−)-catechin gallate (−CG), and (−)-gallocatechin gallate (−GCG) are known to form during heat sterilization in the production of bottled green tea. 1,2) It is well recognized that tea catechins have preventive effects against cancer, heart disease, diabetes, age-related diseases. [3][4][5] Accordingly, study on the metabolism of tea catechins has recently received increased attention in the explanation of their physiological functions.…”

Section: Catechins Such As (+)-Catechin (+C) (−)-Epicatechin (−Ec) mentioning

confidence: 99%

Bioconversion of (−)-Epicatechin, (+)-Epicatechin, (−)-Catechin, and (+)-Catechin by (−)-Epigallocatechin-Metabolizing Bacteria

Takagaki¹,

Nanjo²

2015

Biological & Pharmaceutical Bulletin

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Section: Catechins Such As (+)-Catechin (+C) (−)-Epicatechin (−Ec) mentioning

confidence: 99%

Bioconversion of (−)-Epicatechin, (+)-Epicatechin, (−)-Catechin, and (+)-Catechin by (−)-Epigallocatechin-Metabolizing Bacteria

Takagaki¹,

Nanjo²

2015

Biological & Pharmaceutical Bulletin

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“…Green tea, a popular beverage in Asian countries, contains a series of polyphenols known as catechins, in particular epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and epigallocatechin gallate (EGCG) (3,14,15,21). There is considerable interest in the anti-obesity potential of green tea (24), as several reports have shown that administration of polyphenols resulted in a significant reduction in body weight gain and body fat accumulation induced by a high-fat diet in animal models (9,16,20).…”

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confidence: 99%

Effect of tea catechins on body fat accumulation in rats fed a normal diet

et al. 2008

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Although it is known that tea catechins exert potent effects in obese subjects, there is scant information concerning these effects on body weight gain and body fat accumulation in the non-obese. We studied normal rats fed a normal diet and water containing either 0.1% or 0.5% tea catechins to examine the effects on body fat content and serum cholesterol levels, as well as evaluating whether the effect is related to bile acids, which in recent years have emerged as an inducer of energy expenditure. The administration of 0.5% catechins decreased the accumulation of body fat and the serum levels of cholesterol and bile acids. These results indicate that tea catechins modulate lipid metabolism not only in obese subjects, but also in the non-obese.Green tea, a popular beverage in Asian countries, contains a series of polyphenols known as catechins, in particular epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and epigallocatechin gallate (EGCG) (3, 14, 15, 21). There is considerable interest in the anti-obesity potential of green tea (24), as several reports have shown that administration of polyphenols resulted in a significant reduction in body weight gain and body fat accumulation induced by a high-fat diet in animal models (9,16,20). But despite the great interest, there is scant information concerning the effects of tea catechins on body weight gain and body fat accumulation in non-obese subjects.Bile acids are synthesized from cholesterol in the liver, and secreted after meals to promote absorption of fat from the intestine. Although it has been shown that bile acids also mitigate diet-induced obesity (11), that finding has attracted limited attention. Recently, Watanabe et al. (23) confirmed and expanded this observation, showing that feeding mice with cholic acid moderated the effects of a high-fat diet. The novel metabolic effect of bile acids is critically dependent on inducing energy expenditure by promoting intracellular thyroid hormone activation (23). It is unclear whether the tea catechins-induced reduction in body weight gain is related to increased metabolism induced by bile acids.Therefore, we performed a study in normal rats fed a normal diet to examine the effects on body fat content and the levels of serum cholesterol and bile acids. MATERIALS AND METHODSTea catechins. We used a crude catechin extract (Teafuran 90S; Itoen Ltd, Tokyo, Japan) containing 55.5% (w/w) EGCG and 19% others (EC, ECG, EGC). According to the manufacturer, the total polyphenol content was 94%, and caffeine content was 0.6%.Animals. Male Wistar rats (200-250 g) were purchased at 7 weeks of age (Clea Japan Inc., Tokyo,

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“…In order to determine the equilibrium position for gallated catechins, we carried out epimerization between (-)-EGCg and (-)-GCg using the reported optimum temperature and pH (120 °C, pH 5.5) (Seto et al, 1997).…”

Section: Thermal Epimerization Between (-)-Egcg and (-)-Gcgmentioning

confidence: 99%

“…(Hara, 2001). Epi type catechins undergo epimerization in hot aqueous solutions to yield corresponding non-epi type isomers (Yamamoto et al, 1997;Seto et al, 1997). When canned and bottled tea drinks are manufactured, the products are usually autoclaved for pasteurization at 120 °C for several minutes.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cyclodextrins on the Thermal Epimerization of Tea Catechins

Okumura

Ichitani

Takihara

et al. 2008

FSTR

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The epimerization reaction of tea catechins was investigated at pH 5.5 and 120 °C in the absence/presence of cyclodextrins (CDs). In the absence of CDs, a considerable quantity (~20%) of products originating from reactions other than the epimerization ("other products") was formed during the epimerization of gallated catechins. In the case of (-)-EGCg, addition of β-CD to the reaction solution reduced the quantity of these other products to just a few percent, but other CDs with different cavity sizes had little effect. Generally, the addition of β-CD increased the ratio of non-epi type catechins, that is, [non-epi type catechin] / ([epi type catechin]+[non-epi type catechin]). Molecular orbital (MO) calculations using the PM3 method suggested that non-epi type catechins are more thermodynamically stable than their epitype counterparts, moving the equilibrium position in favor of non-epi type catechins in the epimerization process.

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Preparation of Epimers of Tea Catechins by Heat Treatment

Cited by 185 publications

References 10 publications

Bioconversion of (−)-Epicatechin, (+)-Epicatechin, (−)-Catechin, and (+)-Catechin by (−)-Epigallocatechin-Metabolizing Bacteria

Bioconversion of (−)-Epicatechin, (+)-Epicatechin, (−)-Catechin, and (+)-Catechin by (−)-Epigallocatechin-Metabolizing Bacteria

Effect of tea catechins on body fat accumulation in rats fed a normal diet

Effect of Cyclodextrins on the Thermal Epimerization of Tea Catechins

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