Bactericidal activity of catechin-copper (II) complexes on Escherichia coli ATCC11775 in the absence of hydrogen peroxide

Kimura, Takeshi; Hoshino, Nobuo; Yamaji, Akihiro; Hayakawa, Fumiko; Ando, Takashi

doi:10.1046/j.1472-765x.1998.00458.x

Cited by 12 publications

(11 citation statements)

References 4 publications

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“…The recommended dietary allowance (RDA) for children is 200−400 µg/day while it is about 900 µg/day for adults. EGCG had been shown to chelate Cu 2+ in various systems (Mira et al, 2002;Kimura et al, 1998;Yoshioka et al, 2001;Kumamoto et al, 2001); many previous studies used Cu 2+ to initiate the free-radical oxidation of human low-density lipoproteins. To date, there are no reports of studies to examine the bioactivity of EGCG derivatives and EGCG-Cu 2+ complex.…”

Section: Introductionmentioning

confidence: 99%

Cytotoxicity of epigallocatechin-3-gallate to LNCaP cells in the presence of Cu2+

Shen

Xiong³

2005

J Zheijang Univ Sci B

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Epigallocatechin-3-gallate (EGCG) has shown remarkably anti-cancer activity, with its bioactivity being related to reactive conditions, such as pH and metal ions. The present study investigated the degradation of EGCG and its effect on prostate cancer cell in the presence of Cu 2+. EGCG was incubated with prostate cancer cells, LNCaP, pretreated with or without Cu 2+ . EGCG in F-12 medium was quantified using HPLC and the viability of cells was assessed by gel electrophoresis, flow cytometry, and electron microscope. The results of HPLC showed that EGCG degraded completely within 12 h in F-12 medium with or without Cu 2+. Gel electrophoresis and flow cytometry did not detect apoptosis of LNCaP cells when they were incubated with EGCG. Electron microscopy examination revealed that EGCG-Cu 2+ complex led to damage of cytoplasm membrane in LNCaP cells. It was speculated that not EGCG, but its oxide and complex with Cu 2+ , are the bioactive components responsible for its cytotoxicity to LNCaP prostate cancer cells.

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Section: Introductionmentioning

confidence: 99%

Cytotoxicity of epigallocatechin-3-gallate to LNCaP cells in the presence of Cu2+

Shen

Xiong³

2005

J Zheijang Univ Sci B

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“…[10][11][12][13][14][15] We have reported that, in the presence of Cu 2þ under aerobic conditions, some tea catechins induced DNA cleavage, 16) accelerated the peroxidation of unsaturated fatty acid, 16) and killed bacteria. [17][18][19] These effects are considered due to the prooxidative property of catechins. This activity varies with the structure of a catechin 20) and metal ion.…”

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confidence: 99%

Prooxidative Activities of Tea Catechins in the Presence of Cu²⁺

Hayakawa

Ishizu

Hoshino

et al. 2004

Bioscience, Biotechnology, and Biochemistry

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“…Since these flavonols are abundant in the seed coat of the black jamapa bean, they may also contribute to the generation of hydrogen peroxide (2). Studies with E. coli have shown that the flavonoids catechin, epigallocatechin, and epichatechin in the presence of copper(II) produce bactericidal concentrations of H 2 O 2 (25,26,33). According to Hoshino et al (26), catechin-Cu(II) complexes where Cu(II) is reduced to Cu(I) are formed, and the reoxidation of Cu(I) to Cu(II) by molecular oxygen generates H 2 O 2 .…”

Section: Discussionmentioning

confidence: 99%

Requirement of a Plasmid-Encoded Catalase for Survival ofRhizobium etliCFN42 in a Polyphenol-Rich Environment

Santos¹,

López²,

Cubillas³

et al. 2008

Appl Environ Microbiol

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Nitrogen-fixing bacteria collectively called rhizobia are adapted to live in polyphenol-rich environments. The mechanisms that allow these bacteria to overcome toxic concentrations of plant polyphenols have not been clearly elucidated. We used a crude extract of polyphenols released from the seed coat of the black bean to simulate a polyphenol-rich environment and analyze the response of the bean-nodulating strain Rhizobium etli CFN42. Our results showed that the viability of the wild type as well as that of derivative strains cured of plasmids p42a, p42b, p42c, and p42d or lacking 200 kb of plasmid p42e was not affected in this environment. In contrast, survival of the mutant lacking plasmid p42f was severely diminished. Complementation analysis revealed that the katG gene located on this plasmid, encoding the only catalase present in this bacterium, restored full resistance to testa polyphenols. Our results indicate that oxidation of polyphenols due to interaction with bacterial cells results in the production of a high quantity of H 2 O 2 , whose removal by the katG-encoded catalase plays a key role for cell survival in a polyphenol-rich environment.Flavonoids are a widespread group of polyphenolic compounds in the plant kingdom. Their basic chemical structure consists of two benzene (A and B) rings linked through a heterocyclic pyran or pyrone (C) ring. Substitutions in the C ring give rise to anthocyanidins, flavanols, flavonols, flavones, flavanones, chalcones, and isoflavonoids. Many are esterified at hydroxyl groups with different sugars, commonly glucose, galactose, or rhamnose, to produce glycosides. They are distributed throughout the plant, including in the fruit and seeds.Several groups of bacteria are adapted to live in environments rich in polyphenols, such as the gastrointestinal tracts of ruminants or the rhizosphere, the soil region surrounding the plant root (6, 45). Nitrogen-fixing bacteria belonging to the genera Rhizobium, Sinorhizobium, Mesorhizobium, Bradyrhizobium, and Azorhizobium (collectively called rhizobia) live surrounded by a wide variety of organic substances released by germinating seeds and plant roots, including polyphenolic compounds. Some of the flavonoids exuded by legume seeds and roots induce transcription of rhizobial nodulation (nod, noe, and nol) genes, which allow these bacteria to establish a symbiotic association with their host plant (9, 27). In addition, flavonoids enhance the growth rates of bacterial cells and promote bacterial movement toward the plant (12,22,42). Since root exudation is a highly dynamic process influenced by multiple biotic and abiotic factors, it is very likely that under field growth conditions, rhizobia are constantly exposed to large amounts and wide varieties of polyphenols in addition to the specific nod gene-inducing flavonoids (5). For instance, the presence of multiple microorganisms, including plant pathogens, may influence the quality and quantity of flavonoids produced by the roots (43, 47). It has also been shown that diverse envi...

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Bactericidal activity of catechin-copper (II) complexes on Escherichia coli ATCC11775 in the absence of hydrogen peroxide

Cited by 12 publications

References 4 publications

Cytotoxicity of epigallocatechin-3-gallate to LNCaP cells in the presence of Cu2+

Cytotoxicity of epigallocatechin-3-gallate to LNCaP cells in the presence of Cu2+

Prooxidative Activities of Tea Catechins in the Presence of Cu²⁺

Requirement of a Plasmid-Encoded Catalase for Survival ofRhizobium etliCFN42 in a Polyphenol-Rich Environment

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Bactericidal activity of catechin-copper (II) complexes on Escherichia coli ATCC11775 in the absence of hydrogen peroxide

Cited by 12 publications

References 4 publications

Cytotoxicity of epigallocatechin-3-gallate to LNCaP cells in the presence of Cu2+

Cytotoxicity of epigallocatechin-3-gallate to LNCaP cells in the presence of Cu2+

Prooxidative Activities of Tea Catechins in the Presence of Cu2+

Requirement of a Plasmid-Encoded Catalase for Survival ofRhizobium etliCFN42 in a Polyphenol-Rich Environment

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Prooxidative Activities of Tea Catechins in the Presence of Cu²⁺