Protective Effects of a Topical Antioxidant Complex Containing Vitamins C and E and Ferulic Acid Against Ultraviolet Irradiation-InducedPhotodamage in Chinese Women
April 2013 | Volume 12 | Issue 4 | Original Article | 464 | Copyright © April 2013
Yan Wu MD PhD,a* Xin Zheng,a* Xue-Gang Xu MD,a Yuan-Hong Li MD PhD,a Bin Wang PhD,a Xing-Hua Gao MD PhD,a Hong-Duo Chen MD,a Margarita Yatskayer MS,b and Christian Oresajo PhDb,c
*These authors contributed equally to this study.
aDepartment of Dermatology, No. 1 Hospital of China Medical University, Liaoning, Shenyang, China
bResearch and Innovation, L’Oréal USA, Clark, NJ
cSkinceuticals, Inc, New York, NY
OBJECTIVE: The objective of the study was to investigate whether a topical antioxidant complex containing vitamins C and E and ferulic acid can protect solar-simulated ultraviolet irradiation (ssUVR)-induced acute photodamage in human skin.
METHOD: Twelve healthy female Chinese subjects were enrolled in this study. Four unexposed sites on dorsal skin were marked for the experiment. The products containing antioxidant complex and vehicle were applied onto 2 sites, respectively, for 4 consecutive days. On day 4, the antioxidant complex-treated site, the vehicle-treated site, and the untreated site (positive control) received ssUVR (5 times the minimal erythema dose). The fourth site (negative control) received neither ssUVR nor treatment. Digital photographs were taken, and skin color was measured pre- and postirradiation. Skin biopsies were obtained 24 hours after exposure to ssUVR, for hematoxylin and eosin and immunohistochemical staining.
RESULTS: A single, 5 times the minimal erythema dose of ssUVR substantially induced large amounts of sunburn cell formation, thymine dimer formation, overexpression of p53 protein, and depletion of CD1a+ Langerhans cells. The antioxidant complex containing vitamins C and E and ferulic acid conferred significant protection against biological events compared with other irradiated sites.
CONCLUSION: A topical antioxidant complex containing vitamins C and E and ferulic acid has potential photoprotective effects against ssUVR-induced acute photodamage in human skin. J Drugs Dermatol.
It is well-known that continuous exposure to ultraviolet irradiation (UVR) leads to various of biological effects, including cutaneous erythema, edema, sunburn, immunosuppression, photoaging, as well as skin carcinogenesis.1 One of the mechanisms is that UVR increases the cellular levels of reactive oxygen species (ROS), which damage lipids, proteins, and nucleic acids in both epidermal and dermal cells, and stimulates the inflammatory process in the skin.2
Ultraviolet A (UVA), in a wavelength of 320 to 400 nm, contributes up to 95% of total UV exposure and is a significant source of oxidative stress in human skin.3,4 Experimental findings show that cumulative UVA doses are capable of inducing cellular DNA damage, which may lead to photoaging of the skin, altered expression of oncogenes and tumor suppressor genes, and skin carcinoma.5-7 Ultraviolet B (UVB), in a wavelength of 290 to 320 nm, critically damages cellular macromolecules and induces the formation of ROS. Newly formed ROS, such as hydroxyl radical and superoxide anion, can activate genes, damage DNA, oxidize cell lipids and proteins, and ultimately lead to apoptotic or necrotic cell death.8-10 To protect cells from UVR-induced damage, the skin has an elaborate antioxidant defense system consisting of enzymatic and nonenzymatic components to quench reactive oxygen intermediates.11 However, with the ongoing exposure to UVR, the body’s endogenous antioxidative system will be overwhelmed and the production of ROS increases. Supporting the skin’s antioxidant defense system is a necessary strategy to combat oxidative damage induced by UVR.
Vitamin C (ascorbic acid) and vitamin E (mainly α-tocopherol) are the 2 elemental nutrients that could quench free radicals and prevent ROS-induced cellular damage. Vitamin C can directly scavenge free radicals in the water phase and can protect cellular membranes.12 In contrast, vitamin E is mainly a free radical scavenger in the lipid phase by means of inhibiting lipid peroxidation.13 When vitamin C and vitamin E coexist, they demonstrate synergistic effects.14 Ferulic acid is a potent phenolic antioxidant found ubiquitously and at high concentrations in plants.15 It has been demonstrated that ferulic acid can protect membranes from lipid peroxidation, neutralize alkoxyl radicals, and prevent cells from damage induced by hydroxyl radicals, nitric oxide, and superoxide radical.16 When ferulic acid was incorporated into a formulation of vitamin C and/or vitamin E, the topical delivery of