ABSTRACT
Department of Dermatology, University of California, San Francisco, California, USA TOPALIX, Topical Product Development, San Francisco, California, USA
Introduction 38
Constitutive Skin Antioxidants 39
Water-Soluble Antioxidants 39
Ascorbate 39
Glutathione 42
Urate 44
Lipid-Soluble Antioxidants 44
Vitamin E 44
Ubiquinols/Ubiquinones (“Coenzyme Q”) 45 Carotenoids and Vitamin A 48
Enzymatic Antioxidant Systems 49
Enzymatic GHS System 49
Superoxide Dismutases 50
Catalase 51
Effect of Environmental Stressors on Skin Antioxidants 51
Hydrophilic Skin Antioxidants 52
Lipophilic Skin Antioxidants 53
Enzymatic Skin Antioxidants 54
Role of Antioxidants in the Photoprotection of Skin 55
Topical Application of Antioxidants 55
Vitamin E 55
Vitamin C 63
Other Antioxidants 63
Antioxidant Combinations 70
Topical Application of Antioxidants after UVR Exposure 73
Topical Application of Substances Other than Conventional
Antioxidants 74
Summary and Conclusion 74
Acknowledgments 75
References 75
INTRODUCTION
As the outermost organ of the body, the skin is frequently and directly exposed to
a pro-oxidative environment, including ultraviolet radiation, drugs, and air pollu-
tants (1). Besides dealing with external inducers of oxidative attack, the skin has
to cope with endogenous generation of reactive oxygen species (ROS) and other
free radicals, which are continuously produced during physiological cellular
metabolism. To counteract the harmful effects of ROS, the skin is equipped
with antioxidant systems, which maintain an equilibrium between pro-and
antioxidants.
