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A novel pathway for the photooxidation of catechin in relation to its prooxidative activity.

ABSTRACT: In the present study, we evaluated the prooxidative mode of action of photoirradiated (+)-catechin at 400 nm in relation to reactive oxygen species generation and its possible application to disinfection. Photoirradiation of (+)-catechin at a concentration of 1 mg/mL yielded not only hydrogen peroxide (H₂O₂) but hydroxyl radical (·OH) in a total amount of approximately 20 μM in 10 min. As a result, photoirradiated catechin killed Staphylococcus aureus, and a > 5-log reduction in viable bacteria counts was observed within 20 min. Liquid chromatography-high-resolution-electrospray ionization-mass spectrometry showed that photoirradiation decreased the (+)-catechin peak (molecular formula C₁₅H₁₄O₆) whilst it increased two peaks of a substance with the molecular formula C₁₅H₁₂O₆ with increasing irradiation time. Nuclear magnetic resonance analysis revealed that the two C₁₅H₁₂O₆ peaks were allocated to intramolecular cyclization products that are enantiomers of each other. These results suggest that photoirradiation induces oxidation of (+)-catechin resulting in the reduction of oxygen to generate H₂O₂. This H₂O₂ is then homolytically cleaved to ·OH, and alongside this process, (+)-catechin is finally converted to two intramolecular cyclization products that are different from the quinone structure of the B ring, as proposed previously for the autoxidation and enzymatic oxidation of catechins.

SUBMITTER: Shishido S

PROVIDER: S-EPMC6110801 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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A novel pathway for the photooxidation of catechin in relation to its prooxidative activity.

Shishido Shunichi S Miyano Rei R Nakashima Takuji T Matsuo Hirotaka H Iwatsuki Masato M Nakamura Keisuke K Kanno Taro T Egusa Hiroshi H Niwano Yoshimi Y

Scientific reports 20180827 1

In the present study, we evaluated the prooxidative mode of action of photoirradiated (+)-catechin at 400 nm in relation to reactive oxygen species generation and its possible application to disinfection. Photoirradiation of (+)-catechin at a concentration of 1 mg/mL yielded not only hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) but hydroxyl radical (·OH) in a total amount of approximately 20 μM in 10 min. As a result, photoirradiated catechin killed Staphylococcus aureus, and a > 5-log reducti ...[more]

PMID: 30150642

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A novel pathway for the photooxidation of catechin in relation to its prooxidative activity.

Publications

A novel pathway for the photooxidation of catechin in relation to its prooxidative activity.

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