Counteracting Skin Aging In Vitro by Phytochemicals

The skin is the most extensive organ in the human body. Photo exposure to ultraviolet (UV) rays causes several damages to skin cells, including premature skin aging, the onset of possible DNA mutations, and the risk of developing cancers, including melanoma. Protecting skin from the damaging effects of sun exposure through the application of creams and filters is important to prevent irreversible damages. Several natural extracts and biomolecules with antioxidant activity are widely used in the production of dietary supplements or topical products, for the prevention and treatment of skin affections. Within this context, we pre-treated human skin fibroblasts (HFF1), skin-isolated stem cells (SSCs) and keratinocytes (HaCaT) with two creams containing a specific solar protection factor (SPF) for 72 h and then exposed the cells to UV light. Gene expression analysis was performed for the key cell cycle regulators (p16, p19, p21, p53 and TERT). Cell senescence was assessed by colorimetric assays of beta-galactosidase and antioxidant potential, revealing the ability of treated cells to counteract free radical production as a result of oxidative stress. Finally, possible mutations in DNA induced by photo exposure were studied. The results obtained demonstrated that the tested products elicit positive effects on all skin cell populations, preserving them from photo exposure damages and premature senescence, being also able to increase the DNA repairing mechanisms and inducing a youngest phenotype.