The main effects mediated by reactive oxygen species (ROS) relate to its potential to cause oxidative damage in cells and tissues. Therefore, a ROS burst contributes to cellular dysfunction and can cause a wide range of chronic diseases. Polyphenol such as catechin and resveratrol is capable of scavenging ROS resulting in the prevention of oxidative stress related diseases. In this study, planar catechin (PCat), in which the geometry of catechin is constrained to be planar, was conjugated to metal chelater DTPA. The antioxidative activity of the compound (PCat-DTPA) was evaluated in terms of the capacity to scavenge DPPH radical as an oxyl radical species. The compound (PCat-DTPA) showed weak antioxidative activity compared with planar catechin due to intramolecular hydrogen bonding between DTPA with catechol moiety of catechin structure. Alternatively, in the presence of Fe3+, the antioxidative activity of PCat-DTPA greatly increased 345-fold, which was 3-fold compared to that of PCat. The strong antioxidative activity of PCat-DTPA in the presence of Fe3+ was also shown by Fenton system and hypoxanthin-xanthine oxidase system. Enhanced radical scavenging activity of PCat-DTPA compared with PCat suggested that reduction of DPPH with PCat-DTPA accelerated by Fe3+ mediated electron transfer. Transition metal ions, which have an ability to produce ROS by redox cycle, demonstrates the role of positive oxidative stress in age-related diseases. However, PCat-DTPA exhibits more potent antioxidative activity by coordinating with Fe3+. Therefore, the compound is a promising seed for the new antioxidant for the treatment of the oxidative stress-related diseases.

Planar catechin conjugated with DTPA as a promising antioxidant triggered by Fe3+ coordination

2019 Fall National Meeting

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