Effect of Epigallocatechin-3-gallate on DMPC Oxidation Revealed by Infrared Spectroscopy

The daily exposure of skin cells to the sun increases the rate of production of free radicals, which threatens the healthy appearance of skin and, even more worrying, damages the structural integrity of tissues and DNA, causing inflammation and carcinogenesis. This work demonstrates the feasibility of using natural agents, in particular tea catechins, in protecting lipidic membranes from oxidative stress-induced by UV radiation exposure. For that purpose, thin cast films prepared from vesicular suspensions of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylcholine + (-)-epigallocatechin-3-gallate (DMPC + EGCG) were deposited onto calcium fluoride supports and irradiated with 254 nm UV radiation. The molecular damage after irradiation with UV light was analysed by infrared (IR) together with 2D correlation spectroscopies. Results revealed that the DMPC phospholipid polar moiety is the most vulnerable and sensitive structural target of UV radiation. To check if the presence of the EGCG molecules is protecting the lipids, the principal components analysis (PCA) mathematical method was applied, allowing to conclude that EGCG slows down the cascade of the oxidant-events in the lipid, thus protecting the polar moiety of the lipid.