Photochemoprotective Potential of the Ethyl Acetate Fraction from Eugenia hiemalis Leaves and Its 2,6-Di-O-galloylarbutin Isolate Against UVB-Induced Photodamage

Intense and constant exposure to UVB radiation can lead to inflammation and oxidative stress, which are associated with many cutaneous disorders, including photoaging and skin cancer. Antioxidant plant materials that are rich in polyphenols, such as the ethyl acetate fraction (EAF) from Eugenia hiemalis leaves, and phenolic compounds represent a promising approach to protect the skin against UVB-induced damage. The present study evaluated the photochemoprotective potential of the EAF and its 2,6-di-O-galloylarbutin (1) isolate. The EAF and the phenolic antioxidant (1) reduced UVB-induced L929 fibroblast death. The EAF prevented UVB-induced damage in fibroblasts by inhibiting the intracellular production of reactive oxygen species and lipid peroxidation, especially in pretreated cells. Topical treatment with an emulsion with 1% EAF prevented/attenuated UVB-induced inflammation and oxidative stress in the skin in hairless mice by controlling the increase in myeloperoxidase activity, reducing superoxide anion production, maintaining radical-scavenging ability and ferric reducing power, and controlling the depletion of reduced glutathione and catalase levels. The EAF also inhibited the increase in epidermal thickness, mast cell infiltration, the number of sunburn cells and collagen fiber destruction that were triggered by UVB. The in vitro and in vivo results indicated that the EAF is a bioactive agent that is able to protect the skin against the harmful effects of UVB.