Ferulic acid shields the skin from UVB-induced redness. Ferulic acid, when combined with ascorbic Acid and Vitamin E, can increase the stability of the formulation and double its photoprotection capacity. It also protects the skin from environmental aggressors. Ferulic acid has been shown in clinical trials to have high permeation capacities through the stratum corneum,  due to its lipophilicity properties.
See also:
Antioxidant
Ascorbic Acid
Vitamin E