| Abstract: |
Electromagnetic radiation in the ultraviolet, infrared (IR), and visible (VIS) ranges produces biological effects in humans, but also harmful effects to organs such as the skin, particularly from those that are derived from ultraviolet radiation (UVR). The generation of reactive oxygen species (ROS) by UVR (and, therefore, oxidative-stress production) is one of the mechanisms through which UVR can manifest its possible harmful effects on the skin. A shared feature of skin cancer is that, according to current opinions, they are all related to overexposure to solar or artificial UVR. Topical or systemic photoprotection is an important weapon to avoid the undesirable effects of solar radiation. Topical and oral antioxidants with photoprotective and antiphotocarcinogenic properties could provide therapies to prevent damage from solar radiation. The extract of Polypodium leucotomos (PL, trade name Fernblock, IFC Group, Spain) has a high content of phenolic compounds and is a powerful antioxidant. PL has photoprotective and antiphotocarcinogenic properties. It is administered topically and orally, with proven safety. The protection mechanisms vary and include antioxidant, antiinflammatory, and immunomodulatory effects. PLs provide protection against UVR, IR, and VIS rays and prevent carcinogenesis and aging. The reduction of oxidative stress mediated by PL includes inhibition of the generation and release of ROS. It prevents DNA damage induced by UVR and ROS, inhibits the expression of AP1 and NF-κB, and protects the production of natural antioxidant-enzyme systems. At the cellular level, PL decreases UVR-mediated cell apoptosis, activates the p53 tumor suppressor and inhibits abnormal remodeling of the extracellular matrix. PL prevents immunosuppression and inhibits the expression of the enzyme cyclooxygenase-2 (COX-2), which is induced by UV rays. PL also prevents skin damage induced by visible light and infrared radiation as the expression of MMP-1. PL effects are reflected in the inhibition of carcinogenesis and photoaging. © 2021 Elsevier Inc. |
