Covalent Binding of Tea Catechins to Protein Thiols: The Relationship between Stability and Electrophilic Reactivity

Mori, Tomohisa; Ishii, Takeshi; Akagawa, Mitsugu; Nakamura, Yoshimasa; Nakayama, Tsutomu

doi:10.1271/bbb.100509

Cited by 55 publications

(31 citation statements)

References 31 publications

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“…On the other hand, SKF252a did not show any effect on the PCA-and (+)-catechin-induced enhancement, whereas it showed a tendency to inhibit the BHT-enhanced edema formation (111% versus 136%, P = 0.08). These results suggested that higher amounts of the catechol-type polyphenols, including (+)-catechin, have the potential to enhance skin inflammation through a tyrosinase-dependent bioactivation, even though the catechol-type catechins have a lower antioxidant activity and higher stability compared to the gallate-type catechins, such as (-)-epigallocatechin-3-gallate (Mori et al 2010). In addition, the toxic effects of BHT, possibly through CYP, led us to the idea that more attention should be paid to the administered dose of monophenols not only in the skin, but also in the liver and kidneys, which have significant CYP activities and the potential target tissues for toxic effects of PCA and some tyrosinase substrates (Nakamura et al 2001b;Moridani et al 2002).…”

Section: -3 Results and Discussionmentioning

confidence: 99%

Plant Polyphenols as a Double-Edged Sword in Health Promotion: Lessons from the Experimental Models Using Simple Phenolic Acids

Nakamura¹

2016

AGri-Biosci. Monogr. (AGBM)

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erized molecules such as tannins are reportedly identified. Phenolic acids include caffeic acid, vanillic acid, and coumaric acid, that account for approximately onethird of the total dietary intake of polyphenols. Flavonoids, account for the remaining two-thirds of polyphenol intake, can be further subdivided into 13 classes, including flavones, flavanones, flavonols, isoflavones, catechins (flavanols), anthocyanins and proanthocyanidins, with more than 5,000 identified compounds. Epidemiological studies have supported the hypothesis that high dietary intake of polyphenols is associated with decreased risk of a range of diseases including cardiovascular disease, cancer and neurodegenerative diseases (Fraga 2007;Martin and Appel 2010). Since the French paradox was described two decades ago (Renaud and Lorgeril 1992), several Abstract Polyphenols in foods possess potential to exhibit various beneficial effects in health promotion. Although polyphenols are well known to have antioxidant properties, a wealth of data suggests that most of the relevant mechanisms of disease prevention by polyphenols are not mainly related to their antioxidant properties. The protective function of phenolic compounds, which can be metabolically converted into electrophiles, might be ascribed to the induction of the cytoprotective responses against oxidative stress or toxic chemicals. Based on compelling evidence regarding the beneficial potential of polyphenols, various polyphenol-rich dietary supplements are being developed for public use. It is recently becoming apparent that commonly used dietary compounds can exert deleterious effects at pharmacological (supraphysiological) doses. Moreover, some human intervention trials showed not only failure to protect by polyphenols but accelerated development of chronic diseases in susceptible subjects. Thus, the present monograph tries to provide experimental evidence supporting the idea that optimal polyphenol supplementation can confer beneficial effects but high doses elicit adverse effects in an electrophilic reaction-dependent manner, thereby establishing a double-edge sword in health promotion. Current knowledge of polyphenols as phase II inducers is also discussed, with consideration of the metabolic activation, binding targets and factors influencing the biological activities of polyphenols. In addition, this monograph attempts to provide a brief perspective on the beneficial and harmful effects of food polyphenols. Fig. 1. The major reactions of a catechol type-polyphenol; antioxidant, pro-oxidant, and electrophilic conjugation reactions. Reprinted from Bioscience, Biotechnology and Bioscience, 74(2), Nakamura and Miyoshi, Electrophiles in foods: the current status of isothiocyanates and their chemical biology, 242-255, Fig. 2. Conceptual illustration of electrophile and nucleophile. Reprinted from Bioscience, Biotechnology and Bioscience, 74(2), Nakamura and Miyoshi, Electrophiles in foods: the current status of isothiocyanates and their chemical biology, 242-255,

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Section: -3 Results and Discussionmentioning

confidence: 99%

Plant Polyphenols as a Double-Edged Sword in Health Promotion: Lessons from the Experimental Models Using Simple Phenolic Acids

Nakamura¹

2016

AGri-Biosci. Monogr. (AGBM)

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“…The stability and autoxidation of EGCG are also associated with several factors including pH, temperature, metal ion, antioxidant levels, oxygen levels, concentration of EGCG, and other ingredients in tea [ 66 ]. It is reported that EGCG is more prone to undergo autoxidation at alkaline pH, and the instability is related to their electrophilic reactivity [ 75 ].…”

Section: The Basic Properties Of Egcgmentioning

confidence: 99%

Green Tea Extracts Epigallocatechin-3-gallate for Different Treatments

Chu

Deng

Man

et al. 2017

BioMed Research International

268

157

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Epigallocatechin-3-gallate (EGCG), a component extracted from green tea, has been proved to have multiple effects on human pathological and physiological processes, and its mechanisms are discrepant in cancer, vascularity, bone regeneration, and nervous system. Although there are multiple benefits associated with EGCG, more and more challenges are still needed to get through. For example, EGCG shows low bioactivity via oral administration. This review focuses on effects of EGCG, including anti-cancer, antioxidant, anti-inflammatory, anticollagenase, and antifibrosis effects, to express the potential of EGCG and necessity of further studies in this field.

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“…These results suggested that higher amounts of the catechol-type polyphenols, including (+)-catechin, have the potential to enhance skin inflammation through a tyrosinasedependent bioactivation, even though the catechol-type catechins have a lower antioxidant activity and higher stability compared to the gallate-type catechins, such as (-)-epigallocatechin-3-gallate. 14) In addition, the toxic effects of BHT, possibly through CYP, led us to the idea that much attention should be paid to the administered dose of monophenols not only in the skin, but also in the liver and kidney, which have significant CYP activities and the potential target tissues for toxic effects of PCA and some tyrosinase substrates. 15,16) In the present study, we have indicated that the catechol-type polyphenols can modify sulfhydryl groups in a phenol oxidase-dependent manner.…”

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confidence: 99%

Thiol modification by bioactivated polyphenols and its potential role in skin inflammation

Nakamura

Ishii

Abe

et al. 2014

Bioscience, Biotechnology, and Biochemistry

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In the present study, we evaluated the modifying behavior of simple phenolic compounds on the sulfhydryl groups of glutathione and proteins. The catechol-type polyphenols, including protocatechuic acid, but neither the monophenols nor O-methylated catechol, can modify the sulfhydryl groups in a phenol oxidase-dependent manner. The possible involvement of polyphenol bioactivation in the enhancement of skin inflammation was also suggested.

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Covalent Binding of Tea Catechins to Protein Thiols: The Relationship between Stability and Electrophilic Reactivity

Cited by 55 publications

References 31 publications

Plant Polyphenols as a Double-Edged Sword in Health Promotion: Lessons from the Experimental Models Using Simple Phenolic Acids

Plant Polyphenols as a Double-Edged Sword in Health Promotion: Lessons from the Experimental Models Using Simple Phenolic Acids

Green Tea Extracts Epigallocatechin-3-gallate for Different Treatments

Thiol modification by bioactivated polyphenols and its potential role in skin inflammation

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