Photoprotective Effect of Annona muricata L. Extracts in Rats Exposed to Ultraviolet Radiation via P53 and RB Gene Expression.

A current problem is the increase in skin damage, including cancer, caused mainly by prolonged exposure to ultraviolet rays from sunlight. Therefore, the aim of this work was to study the photoprotective effect to ultraviolet radiation of phenolics and acetogenic-rich extracts obtained from Annona muricata leaves applied to the skin of rats by means of gene expression in P53 and Rb, involved in tumor processes due to cell damage, in addition to the content of phenols, acetogenins and antioxidant activity present in the extract, which presented a total phenol content of 61.5 mg EAG/100 g of dry sample and flavonoids of 50 mg EQ/100 g. HPLC analysis revealed that the major compound was shikimic acid, followed by gallocatechin and 13 other phenols. DPPH analysis showed an inhibition of 64.37% and FRAP showed a value of 28,880 µmol Eq trolox/mL. The presence of acetogenins was verified by Kedde's reagent in HPTLC. Histopathological findings in the treated groups (T4, T5) suggest thickening of the epidermis, which could be due to fibroblast proliferation. The results show a higher increase in P53 and Rb gene expression with the tested extracts compared to the positive control group, so it can be concluded that the extracts have positive effects.