Sunscreen protection against ultraviolet-induced oxidative stress: evaluation of reduced glutathione levels, metalloproteinase secretion, and myeloperoxidase activity.

Several studies have demonstrated the skin protection by sunscreens considering the aspects skin penetration, photostability, and protection against erythema and sunburn. However, little is known about the effect of topically applied sunscreen formulations on the antioxidant defense, metalloproteinases, and inflammatory processes of skin in response to UVR exposure. Therefore, this study aimed to investigate the use of a cream gel formulation containing the UV filters benzophenone-3, octyl methoxycinnamate, and octyl salicylate to prevent skin damage from a single dose of UVR (2.87 J/cm2). This protective effect was evaluated in vivo by measuring the following biochemical parameters: reduced glutathione levels, secretion of matrix metalloproteinases, and myeloperoxidase activity. The results showed that the sunscreen formulation, despite having sun protection factor (SPF) 15, was not completely effective to protect the skin against GSH depletion, MMP-9 secretion and the inflammatory process induced by UVR. These results demonstrate the importance of analyzing UV-altered biochemical parameters of skin in order to propose new sunscreen formulations that can completely protect skin against UVR-induced damage.

Development of topical functionalized formulations added with propolis extract: stability, cutaneous absorption and in vivo studies.

Propolis, which is a natural product widely consumed in the folk medicine, is a serious candidate to be applied topically due to its outstanding antioxidant properties. So, the purpose of this study was to develop stable topical formulations added with propolis extract in an attempt to prevent and/or treat the diseases occurring in skin caused by UV radiation. The antioxidant activity using a chemiluminescent method was used to evaluate the functional stability and the permeation/retention in skin of these formulations. In the long-term stability study, the formulations were stored at 25+/-2 degrees C/AH and at 40+/-2 degrees C/70% RH for 360 days. It was found in this study, that the formulations prepared with Polawax showed functional and physical stability in the period of study. In addition, this formulation presented good results in the percutaneous study, allowing the antioxidant compounds present in the propolis extract to reach lower layers in pig ear skin and in the whole hairless mice skin (retention=0.12 and 0.13 microL of propolis/g of skin, respectively). In the in vivo study, it was also suggested that this formulation may be effective in protecting skin from UVB photodamage, nevertheless other assays need to be done in order to have a complete understanding of the protective effect of formulations added with propolis extract.