Figure 6.
Schematic representation of yellowing of the dermis by carbonyl adducts: photoexposure (especially UVA radiation), induces free radicals which can directly attack polyunsaturates fatty acids (PUFAS) in membranes and initiate lipid peroxidation. PUFAs are degraded to a variety of products. Some of them such as aldehydes (e.g., MDA, 4-HNE, acrolein) are very reactive and can damage proteins and cause the yellowing observed in our study.