In Brazil, non-melanoma is the most frequent type of skin cancer, representing about 25% of all tumors diagnosed in all geographic regions. Ultraviolet radiation (UVR) from the sun is its biggest etiological agent. Cellular and structural changes arise as a result of an association between UVR and chronological aging. Different strategies are used for prevention and treatment of photoaging. Phytochemical analysis of many plants used for this purpose have shown that these substances containing antioxidants have significant effects on prevention and treatment of photoaging. Many studies on the pharmacology and phytochemical fruit of Lycium barbarum demonstrated that it presents a large amount of polysaccharides, which is the main active ingredient with antioxidant, antitumor and immunomodulatory effects. In order to obtain the polysaccharide fraction (LBP), it was weighed 300 g of dried and triturated fruit from L. barbarum and added 2L of ethanol 95% at a temperature of 75° C for 5 hours (HEE) under reflux to remove the lipids. This procedure was performed three times and the supernatant of extractions, after filtration, were concentrated in rotaevaporator, reserved and called HEE extract. Then, the residue was extracted 4 times with 1 L of distilled water (each time), 3 in 3 hours apart from each other at room temperature. The extract (4 L) was filtered through qualitative filter paper and lyophilized; its volume was reduced by 10 times (400 mL). Afterwards, the material obtained was precipitated in 95% ethanol (4 L) for 12 hours at 4 ° C. The extract was filtered under vacuum and the residue washed with absolute ethanol, acetone and ether successively. The washed precipitate had a final mass of 13 g. This was defined as polysaccharides fraction (LBP) and stored in a freezer (± 20 ° C). Antioxidant activity assays were performed by DPPH method, with extracts of HEE and with the fraction of LBP. The antioxidant activity of ascorbic acid (positive control) was significantly higher (P <0.001) than the activity of all concentrations and test samples. When the activity of the HEE was evaluated and compared with LBP fraction, it was observed a significant difference between the two samples, where the HEE have higher antioxidant potential than the LBP fraction in concentrations of 100 mg / mL (P <0.001), 50 ug / mL (P <0.001), 25 ug / mL (P <0.001), and 3.12 ug / mL (P <0.05). However, at a concentration of 1.56 mg / mL, no significant difference between the two samples is observed, indicating that, at this concentration, the inhibition of oxidative potential is similar for both the HEE and the LBP fraction. Thus, it is clear that choosing any of the samples for testing in the animal model would be effective. We chose to test the antioxidant potential of LBP fraction on the skin of artificially photo-aged hairless mice due to findings in the literature, which used the LBP fraction application in other experimental models, nevertheless with the same goals.
Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP
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