A Topical Antioxidant Solution Containing Vitamins C and E with Ferulic Acid Protects Human Skin from Sunlight Damage and DNA Mutations Associated with Skin Cancer

Presented by John C. Murray, M.D., James A. Burch, Mary Ann Iannacchione RN, CCRP, & Sheldon R. Pinnell, M.D.
Presentations From The Academy for Investigative Dermatology

Sunlight exposure generates oxidative stress in skin that can result in photodamage, including photoaging and skin cancer. The body uses antioxidants to neutralize oxidation of nucleic acids, proteins and lipids; but protection achieved by oral ingestion is limited (Placzek et al., 2005). To augment antioxidant protection, the authors developed and reported three generations of topical antioxidant formulations, each with progressively better protection against solar simulated radiation. The current formulation contains physiologic antioxidants, vitamins C and E, stabilized by a potent plant antioxidant, ferulic acid; optimized for chemical stability, percutaneous absorption, and photoprotection (Lin et al., 2005).

In this study, conducted at Duke University Medical Center, with the approval of the Duke Institutional Review Board, two different solutions were applied to back skin of human volunteers daily for 4 days. One solution was an aqueous solution containing 15% L-ascorbic acid, 1% dltocopherol and 0.5% trans ferulic acid (C E Ferulic); the other, a vehicle control solution. On day 4, solar simulated ultraviolet radiation, passed through a WG295 Schott selective UVB band high pass filter to eliminate wavelengths less than 295 nm was administered to each patch of treated skin. The vehicle patch received 2-6x MED and the C E Ferulic patch received 2-10x MED of solar-simulated irradiation, each at 2x MED intervals. One day later, skin was evaluated by colorimeter for erythema and biopsies of 6x MED-irradiated skin were evaluated for sunburn cells. Erythema was measured by computerized colorimetry evaluation in the “a” mode of digital skin photographs (Tournas, 2005). Each spot and adjacent unirradiated skin was measured in triplicate. The difference between irradiated and unirradiated skin determined the erythema. Sunburn cells were determined in-fixed 8mm punch biopsy sections stained with hematoxylin and eosin. An additional 4 subjects who received 1-5x MED of solar simulated irradiation were biopsied for immunohistochemistry.

Results

C E Ferulic provided substantial protection against erythema. At 2-6x MED irradiance, colorimeter readings for vehicle vs. C E Ferulic revealed significant photoprotection by C E Ferulic. Moreover, C E Ferulic provided significant protection at 8x MED and 10x MED when compared to 6x MED irradiated vehicle-treated skin. Also, sunburn cell enumeration of 6x MED-irradiated skin revealed significant protection by C E Ferulic, Immunohistochemistry of skin receiving 2x MED revealed virtually complete protection by C E Ferulic against UV-generation.

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