Antioxidant capacity of (+)-catechin visible-light photoirradiated in the presence of vitamin B-2

作者：Barua M G; Escalada J P; Bregliani M; Pajares A; Criado S^*

来源：Redox Report, 2017, 22(6): 282-289.

DOI：10.1080/13510002.2016.1240287

• Antioxidants
• catechins
• vitamin B-2
• reactive oxygen species
• photodegradation
• riboflavin

Objectives: Catechins are important components of human diet and have received special attention due to their antioxidant capacity. The purpose of this paper was to study the antioxidant action of (+)-catechin (CTQ) in the presence of vitamin B-2 (riboflavin) as light-absorbing agent. Furthermore, two model compounds, catechol (CTC) and resorcinol (RSC), were selected in order to elucidate the reactive target of the CTQ molecule. The influence of pH-medium was investigated.
Methods: Stationary photolysis, polarographic detection of dissolved oxygen, reactive oxygen species (ROS)-scavengers, time-resolved near-IR phosphorescence detection, stationary, and time-resolved fluorescence and laser flash photolysis techniques were employed.
Results: CTQ interacts with riboflavin under visible-light photoirradiation as well as with different ROS which are generated in this mechanism. Radical-scavenging activity increases with increasing of pH-medium.
Discussion: pH-effect of the medium on radical-scavenging activity comes from the increased electron-donating ability of CTQ upon deprotonation. These results are very interesting due to the fact that the pH of the food products displays important variations.
The O-2((1)Delta(g))-scavenging ability of CTQ, would be equal to the additive contribution of each reactive center, CTC, and RSC, present at the molecule of CTQ. However, CTQ would have a moderate ability to removal of O-2((1)Delta(g))-species at pH 7.

• 出版日期2017