Atividade fotoprotetora de extratos vegetais: uma revisão da literatura

Abstract

Ultraviolet radiation generates photochemical reactions in the skin due to electron excitation in chromophoric molecules, interacting directly with molecular substrates such as DNA in type I sensitization reactions or indirectly, with the production of free radicals in the photo- type II awareness. Exposures to this radiation lead to unwanted effects from a simple skin burn to more serious problems such as skin cancer. This work aims to perform a literature review of the last five years on the evaluation of the photoprotective activity of plant extracts. National and international references available in books, scientific articles, theses and magazines were consulted in the Medline/PubMed, SCIELO, LILACS and Google Scholar databases. The first sunscreens launched on the market were developed in order to protect the skin against sunburn, protecting against UVB radiation, yet they allowed a tanning by UVA radiation. However, with the increase in knowledge about the deleterious effects caused by UVA radiation, it became clear that in addition to protection against UVB radiation, UVA photoprotection is also necessary to reduce changes in photoaging and the risk of skin cancer due to sun exposure. Many of the studies aimed at analyzing the photoprotection of plant extracts show, besides the good result of photoprotection against UVB radiation, productive responses as to their antioxidant function, which is highly desired for cosmetic products, in view of giving these products the reduction or delay of photoaging, showing the benefit of the association of these extracts with the photoprotectors, therefore, the analysis of photoprotective activity of plant extracts is a matter of utmost importance, in addition to being a promising branch in the country's pharmaceutical industry, due to its vast flora.