Ascorbic acid modifies the free radical scavenging behaviour of catechin: An insight into the mechanism

作者：Mahmoud Mohamed Ahmed Abbas; Chedea Veronica Sanda; Detsi Anastasia; Kefalas Panagiotis^*

来源：Food Research International, 2013, 51(2): 907-913.

DOI：10.1016/j.foodres.2013.02.023

• Catechin
• Ascorbic acid
• Antioxidant/pro-oxidant
• Dimerisation
• o-Quinone

In this study, the behaviour of catechin (Cat) and ascorbic acid (AA) and their mixtures at different ratios was studied in view of elaborating predictions over an eventual pro-oxidant or synergistic antioxidant activity. The Co(II)-EDTA luminol chemiluminescence showed that the mixture of Cat:AA (3:1) had the highest antioxidant activity, while the mixture of Cat:AA (1:2) the most pronounced pro-oxidant activity. As the concentration of AA increases, the antioxidant behaviour of the mixture increases strongly as well. The LC-MS analysis for the two mixtures (Cat:AA at ratios of 1:2 and 1:3) revealed that the sufficient of AA accounts for the good antioxidant behaviour of catechin (Cat:AA 1:3 with an IC50 of 47.61 +/- 0.00 mu M and the mixture Cat:AA 1:2 with an IC50 of 75.32 +/- 0.86 mu M as assessed by chemiluminescence), supported by the formation of structure I (m/z 183). As its concentration decreases, the antioxidant activity drops and this is attributed to the formation of structure II (m/z 255). However, when AA becomes lesser beyond this point, a re-strengthening of the antioxidant behaviour has been observed, which may be assigned to the formation of procyanidin structures. Thus, AA may suppress the formation of procyanidin, i.e. creation of C-C bonds between the catechin units.

• 出版日期2013-5