Ferulic and caffeic acids as potential protective agents against photooxidative skin damage

The biological properties and, particularly, the antioxidant activity of plant hydroxycinnamic acids, such as caffeic and ferulic acids, are well recognised. This preliminary study was designed to estimate the potential utility of caffeic and ferulic acids to prevent, when topically applied, photooxidative stress in the skin. With this aim we have evaluated the antioxidant activity of ferulic and caffeic acids in two experimental models: (1) the UV radiation-induced peroxidation in phosphatidylcholine (PC) liposomal membranes; (2) the scavenging activity against nitric oxide (a radical involved in oxidative reactions). In addition, given that a suitable percutaneous absorption is an essential requirement for successful topical photoprotective agents, we measured their in vitro permeation through excised human skin. Caffeic and ferulic acids efficiently protected PC liposomes from UV radiation-induced peroxidation and reacted with nitrogen oxides. In addition, caffeic and ferulic acids were able to permeate through the stratum corneum (the main barrier against the penetration of exogenous substances through the skin). Taken together, these findings suggest that caffeic and ferulic acids should be good canditates for successful employment as topical protective agents against UV radiation-induced skin damage. (C) 1999 Society of Chemical Industry.