A Study of Catechin Photostability Using Photolytic Processing

Shiuh-Tsuen Huang,Meei-Ju Yang,Chien-Wei Cheng,Ji-Yuan Liang,Shwu-Yuan Lee,Jeu-Ming P Yuann

doi:10.3390/pr9020293

Shiuh-Tsuen Huang, Meei-Ju Yang + Show 4 more

Open Access

https://doi.org/10.3390/pr9020293

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Abstract

Catechin exhibits numerous physiological characteristics. In this study, we determined the photosensitivity of catechin to various lights under alkaline conditions, and the mechanisms by which catechin generates free radical species and polymerizes via a photoreaction. In addition to this, the application of catechin photolysis was investigated. A solution of catechin is transparent, but turns yellowish under blue light illumination (BLI) in neutral or weak alkaline solutions. When catechin is subjected to BLI, a dimeric catechin (proanthocyanidin) and a superoxide anion radical (O2•−) are generated in a photolytic reaction. When ascorbic acid or gallic acid is added to catechin and the mixture is subjected to BLI at alkaline pH, fewer catechin dimers and less O2•− are produced, because both acids inhibit the photosensitive oxidation of catechin. When AlCl3 is added to catechin and the mixture is subjected to BLI at pH 8, a photolytic reaction is suppressed by AlCl3, and AlCl3 acts as a catalyst for the disconnection of proanthocyanidin during photolysis. Under alkaline conditions, catechin generates O2•− via photosensitive oxidation, which suppresses the growth of Acinetobacter baumannii (A. baumannii) by at least 4 logs, and deactivates its multi-drug-resistant strain. This study shows that catechin photolysis is a process of oxidation, and that it can be safely applied as a tool for environmental applications.

Highlights

Phenolic compounds are secondary metabolites within plants, and most are polyhydroxyl examples
The when radical-scavenging ability of catechin because compounds is a feature of tea, butThe tea are bottled during manufacturing, catechin is unstable beverages are unstable when bottled during manufacturing, because catechin is unstable oxidative brown reaction of green tea catechin can affect the taste of the tea [8]
The signal intensities for catechin and dimeric catechin (Btype proanthocyanidin), as measured by high performance liquid chromatography and mass spectrometry (HPLC-MS), were negatively correlated with the pH change, and catechin is unstable in alkaline or neutral conditions when subjected to blue light illumination (BLI) [11]