A topical antioxidant solution containing vitamins C and E stabilized by ferulic acid provides protection for human skin against damage caused by ultraviolet irradiation

Background

Skin cancer and photoaging changes result from ultraviolet (UV)-induced oxidative stress. Topical antioxidants may protect skin from these effects.

Objective

We sought to determine whether a stable topical formulation of 15% L-ascorbic acid, 1% alpha-tocopherol, and 0.5% ferulic acid (CEFer) could protect human skin in vivo from substantial amounts of solar-simulated UV radiation.

Methods

CEFer and its vehicle were applied to separate patches of normal-appearing human skin for 4 days. Each patch was irradiated with solar-simulated UV, 2 to 10 minimal erythema doses, at 2-minimal erythema dose intervals. One day later, skin was evaluated for erythema and sunburn cells, and immunohistochemically for thymine dimers and p53. UV-induced cytokine formation, including interleukin (IL)-1α, IL-6, IL-8, and IL-10, and tumor necrosis factor-α, were evaluated by real-time polymerase chain reaction.

Results

CEFer provided significant and meaningful photoprotection for skin by all methods of evaluation.

Limitations

The number of patients evaluated was relatively small.

Conclusion

CEFer provided substantial UV photoprotection for skin. It is particularly effective for reducing thymine dimer mutations known to be associated with skin cancer. Its mechanism of action is different from sunscreens and would be expected to supplement the sun protection provided by sunscreens.

Abbreviations used: cDNA, complementary DNA, CEFer, 15% L-ascorbic acid, 1% alpha-tocopherol, and 0.5% ferulic acid, IL, interleukin, MED, minimal erythema dose, mRNA, messenger RNA, PBS, phosphate-buffered saline, PCR, polymerase chain reaction, RT, real time, TNF, tumor necrosis factor, UV, ultraviolet