scholarly journals A Study of Catechin Photostability Using Photolytic Processing

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 293
Author(s):  
Jeu-Ming P. Yuann ◽  
Shwu-Yuan Lee ◽  
Meei-Ju Yang ◽  
Shiuh-Tsuen Huang ◽  
Chien-Wei Cheng ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Alkaline Solutions ◽  
Light Illumination ◽  
Drug Resistant ◽  
Alkaline Ph ◽  
Radical Species ◽  
Alkaline Conditions ◽  
Photolytic Reaction

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.

scholarly journals Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography–Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5985
Author(s):  
Meei-Ju Yang ◽  
Shwu-Yuan Lee ◽  
Chieh-I Liu ◽  
Shih-Hsuan Chen ◽  
Iou-Zen Chen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Aluminum Chloride ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Structural Changes ◽  
Liquid Chromatography Mass Spectrometry ◽  
Relative Percentage ◽  
Alkaline Conditions

Tea is rich in catechins and aluminum. In this study, the process of catechin photolysis was applied as a model for examining the effects of aluminum chloride (AlCl3) on the structural changes of catechin and the alteration of aluminum complexes under blue light irradiation (BLI) at pH 8 using liquid chromatography and mass spectrometry techniques. Additionally, the effects of anions on catechin upon the addition of AlCl3 and treatment with BLI were also studied. In this study, when 1 mM catechin was treated with BLI, a superoxide anion radical (O2•−) was generated in an air-saturated aqueous solution, in addition to forming a dimeric catechin (proanthocyanidin) via a photon-induced redox reaction. The relative percentage of catechin was found to be 59.0 and 95.7 for catechin treated with BLI and catechin upon the addition of 1 mM AlCl3 treated with BLI, respectively. It suggested that catechin treated with BLI could be suppressed by AlCl3, while AlCl3 did not form a complex with catechin in the photolytic system. However, under the same conditions, it was also found that the addition of AlCl3 inhibited the photolytic formation of O2•−, and reduced the generation of proanthocyanidin, suggesting that the disconnection of proanthocyanidin was achieved by AlCl3 acting as a catalyst under treatment with BLI. The influence of 1 mM fluoride (F−) and 1 mM oxalate (C2O42−) ions on the photolysis of 1 mM catechin upon the addition of 1 mM AlCl3 and treatment with BLI was found to be insignificant, implying that, during the photolysis of catechin, the Al species were either neutral or negatively charged and the aluminum species did not form a complex with anions in the photolytic system. Therefore, aluminum, which is an amphoteric species, has an inherent potential to stabilize the photolysis of catechin in an alkaline conditions, while suppressing the O2•− and proanthocyanidin generation via aluminum ion catalysis in the catechin/Al system under treatment with BLI.

Optimization of Pyrogallol Autoxidation Conditions and Its Application in Evaluation of Superoxide Anion Radical Scavenging Capacity for Four Antioxidants

2016 ◽  
Vol 99 (2) ◽  
pp. 504-511 ◽  
Author(s):  
Qing-An Zhang ◽  
Xi Wang ◽  
Yun Song ◽  
Xue-Hui Fan ◽  
Juan Francisco García Martín
Keyword(s):  
Ascorbic Acid ◽  
Antioxidant Capacity ◽  
Gallic Acid ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Superoxide Anion Radical ◽  
Scavenging Activity ◽  
Pyrogallol Autoxidation

Abstract In this study, some factors influencing pyrogallol autoxidation, including EDTA, temperature, and solvent, were systematically investigated to improve its feasibility in the evaluation of antioxidants for the first time. Subsequently, the improved pyrogallol autoxidation conditions were used to assess the superoxide anion scavenging activity (SASA) of four commonly used antioxidants, namely, ascorbic acid, rutin, catechin, and gallic acid, by both the reaction rate method and the terminated method. The results indicate that pyrogallol autoxidation could be successfully used to determine the antioxidant capacity of ascorbic acid and rutin, which correspondingly suggests the feasibility of its use to measure the superoxide anion radical scavenging activity of polysaccharides and flavonols, because these compounds have a similar basic structural unit as ascorbic acid and rutin, respectively. Unexpectedly, however, pyrogallol autoxidation cannot be used to evaluate the SASA of catechin and gallic acid, although their good antioxidant capacity was confirmed by the 1,1-diphenyl-2-picrylhydrazyl assay. Together, these results suggest the importance of noting the conditions used for pyrogallol autoxidation when assessing the SASA of targeted compounds.

Superoxide Anion Radical: Generation and Detection in Cellular and Non-Cellular Systems

2015 ◽  
Vol 22 (37) ◽  
pp. 4234-4256 ◽  
Author(s):  
Renan Chiste ◽  
Marisa Freitas ◽  
Adriana Mercadante ◽  
Eduarda Fernandes
Keyword(s):  
Superoxide Anion ◽  
Anion Radical ◽  
Cellular Systems ◽  
Superoxide Anion Radical ◽  
Radical Generation

scholarly journals Effect of extraction conditions of paprika oleoresins on their free radical scavenging and anticancer activity

2014 ◽  
Vol 12 (3) ◽  
pp. 377-385 ◽  
Author(s):  
Vesna Šaponjac ◽  
Dragana Četojević-Simin ◽  
Gordana Ćetković ◽  
Jasna Čanadanović-Brunet ◽  
Sonja Djilas ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Cell Line ◽  
Antiproliferative Activity ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Radical Scavenging ◽  
Superoxide Anion Radical ◽  
Food Ingredients ◽  
Supercritical Carbon

AbstractGround spice paprika was extracted with hexane, by conventional Soxhlet procedure (SX oleoresin), and with supercritical carbon dioxide at three different pressures — 20, 30 and 40 MPa (SF20, SF30 and SF40 oleoresins). The effect of extraction method and conditions on the colour intesity of paprika oleoresins, content of α-tocopherol, as well as antioxidant and antiproliferative activity was examined. Hexane showed highest selectivity for paprika pigments (886.02 ASTA), while α-tocopherol showed highest solubility (3846.9 mg kg−1) in supercritical carbon dioxide at 20 MPa. All paprika oleoresins exhibited good superoxide anion radical scavenging activity SF30 being the best superoxide anion radical scavenger. Cell growth activity was evaluated in vitro in human cell lines:cervix epitheloid carcinoma (HeLa), breast adenocarcinoma (MCF7) and colon adenocarcinoma (HT-29). The highest antiproliferative activity was exhibited by SX in MCF7 cell line (IC50=14.28 mg mL−1). Extract SF40 produced significant and selective antiproliferative action towards HeLa cell line. These results suggest that paprika oleoresins, due to high antiradical and tumor cell-inhibiting activity, can be regarded as functional food ingredients.

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