A IMPORTÂNCIA DA PROTEÇÃO TÓPICA E MECÂNICA PARA PREVENÇÃO DO CÂNCER DE PELE

Introdução: O câncer de pele é a neoplasia mais frequente no Brasil. Sua incidência está relacionada, mormente, à exposição aos raios ultravioletas (UV), fator associado à ausência de prevenção. Destarte, é evidente a necessidade dos cuidados com a pele, mediante uso de protetor solar, de acordo com o local do corpo a ser protegido e o tipo de pele. Simultaneamente, urge a diminuição da exposição aos raios solares. Objetivo: Realizar uma revisão de literatura reconhecendo a importância da proteção solar como método efetivo na prevenção do câncer de pele. Materiais e métodos: Foi realizada uma revisão de literatura a partir da análise de 13 publicações científicas publicadas entre 2013 e 2020. Destes, foram selecionados sete, na base de dados PubMed e Scielo, utilizando como termos de pesquisa: “Skin Neoplasms”, “Sunscreening Agents” e “Oncology”, terminologias de acordo com o sistema de Descritores em Ciências da Saúde (DeCs). Resultados: Estudos constataram a possibilidade de 90% dos cânceres de pele não melanomas e 65% dos melanomas estarem associados à exposição solar inadequada. Isso se deve, comumente, à falta de informação da população acerca da prevenção, fato evidenciado pela postura dos principais grupos de risco do câncer de pele (trabalhadores expostos ao ar livre). De acordo com pesquisas, muitos desses declararam que nunca ou raramente usavam camisa de manga comprida e chapéu. Portanto, são necessárias maiores explanações a respeito da necessidade da aplicação diária de proteção solar e do uso de roupas fotoprotetoras, além de evitar exposição solar direta, principalmente das 10 às 16 horas. Conclusão: Destarte, conclui-se que são necessárias mais medidas fotoeducativas, a exemplo da disseminação de informações acerca da necessidade do uso regular de protetor solar, com, no mínimo, fator de proteção solar (FPS) 30, além de estratégias de fotoproteção mecânica, com o intuito de prevenir o câncer cutâneo.

The Involvement of Xanthone and (E)-Cinnamoyl Chromophores for the Design and Synthesis of Novel Sunscreening Agents

Excessive UV exposure contributes to several pathological conditions like skin burns, erythema, premature skin aging, photodermatoses, immunosuppression, and skin carcinogenesis. Effective protection from UV radiation may be achieved with the use of sunscreens containing UV filters. Currently used UV filters are characterized by some limitations including systemic absorption, endocrine disruption, skin allergy induction, and cytotoxicity. In the research centers all over the world new molecules are developed to improve the safety, photostability, solubility, and absorption profile of new derivatives. In our study, we designed and synthesized seventeen novel molecules by combining in the structures two chromophores: xanthone and (E)-cinnamoyl moiety. The ultraviolet spectroscopic properties of the tested compounds were confirmed in chloroform solutions. They acted as UVB or UVA/UVB absorbers. The most promising compound 9 (6-methoxy-9-oxo-9H-xanthen-2-yl)methyl (E)-3-(2,4-dimethoxyphenyl)acrylate) absorbed UV radiation in the range 290–369 nm. Its photoprotective activity and functional photostability were further evaluated after wet milling and incorporation in the cream base. This tested formulation with compound 9 possessed very beneficial UV protection parameters (SPFin vitro of 19.69 ± 0.46 and UVA PF of 12.64 ± 0.32) which were similar as broad-spectrum UV filter tris-biphenyl triazine. Additionally, compound 9 was characterized by high values of critical wavelength (381 nm) and UVA/UVB ratio (0.830) thus it was a good candidate for broad-spectrum UV filter and it might protect skin against UVA-induced photoaging. Compound 9 were also shown to be photostable, non-cytotoxic at concentrations up to 50 µM when tested on five cell lines, and non-mutagenic in Ames test. It also possessed no estrogenic activity, according to the results of MCF-7 breast cancer model. Additionally, its favorable lipophilicity (miLogP = 5.62) does not predispose it to penetrate across the skin after topical application.

Development of Sunscreen Products Containing Titanium Dioxide and Aloe vera Gel

This study aimed to develop sunscreen emulsion from natural sunscreening agents, titanium dioxide and Aloe vera gel extract that have good sun protection efficacy. The effects of formulation variables i.e., particle size and amount of titanium dioxide, amount of Aloe vera gel extract (spray dried powder) and combination of sunscreening agents (titanium dioxide and Aloe vera gel extract) on physical properties and sun protection efficacy (e.g., SPF, UVA/UVB ratio, critical wavelength) of sunscreen products were evaluated. The results showed that the smaller particle size of titanium dioxide improved the sun protection efficacy and increased the UVB absorption edge of the products. SPF of the formulations could be ranked as Nanofine TiO2 (particle size 25–30 nm) > Kingruti T-01 TiO2 (particle size 200 nm) > Pigment TiO2 (particle size < 45,000 nm) and UVA/UVB ratio and critical wavelength of the formulations could be arranged in order as follows: Nanofine TiO2 < Kingruti T-01 TiO2 < Pigment TiO2. Increasing amount of titanium dioxide from 5 to 15 %w/w increased significantly viscosity and SPF of formulations. Aloe vera gel extract itself did not significantly affect SPF, however, combination of Aloe vera gel extract and titanium dioxide seemed to have synergistic effect on sun protection efficacy and decreased viscosity of the formulation. According to the results, the good sunscreen formulation consisted of 15 %w/w Nanofine TiO2, 5 %w/w Aloe vera gel spray dried powder in emulsion base because it was broad spectrum sunscreen and showed high SPF (27.53±1.92), high UVA/UVB ratio with critical wavelength higher than 370 nm.