ANCONA, Italy—Due to recent incorporations of antioxidants into sunscreens, nitroxides—a class of compounds with versatile antioxidant activity—have been developed and studied for their photo-protective effects—when attached to a popular UV filter in sunscreens—on reactive oxygen species (ROS) production (which is a result of skin exposure to UVA radiation) and induction of matrix metalloproteinase-1 (MMP-1), responsible for collagen damage and photo-aging.
These effects were assessed in human dermal fibroblasts exposed to UVA and compared with vitamin E (J Dermatolog Sci. 2011;63(1):55-61). Exposure of fibroblasts to 18J/cm2 UVA lead to a two-fold increase in ROS production, which was reduced to non-irradiated control levels in the presence of 50μM nitroxide compounds and vitamin E. Under the same conditions, a ten-fold increase in MMP-1 mRNA expression levels was observed 24hours post-UVA treatment, which was significantly reduced by all nitroxide compounds, but not vitamin E. These results support the potential use of nitroxide compounds, including novel nitroxide-based UV filters, as a useful and alternative strategy for improving the efficacy of topical formulations against photo-aging and possibly photo-carcinogenesis.
