Rosmarinus officinalis extract-loaded emulgel prevents UVB irradiation damage to the skin

UVB-irradiation increases the risk of various skin disorders, therefore leading to inflammation and oxidative stress. In this sense, antioxidant-rich herbs such as Rosmarinus officinalis may be useful in minimizing the damage promoted by reactive oxygen species. In this work, we report the efficacy of a R. officinalis hydroethanolic extract (ROe)-loaded emulgel in preventing UVB-related skin damage. Total phenols were determined using Folin-Ciocalteu assay, and the main phytocomponents in the extract were identified by UHPLC-HRMS. Moreover, in vitro sun protection factor (SPF) value of ROe was also assessed, and we investigated the in vivo protective effect of an emulgel containing ROe against UVB-induced damage in an animal model. The ROe exhibited commercially viable SPF activity (7.56 ± 0.16) and remarkable polyphenolic content (24.15 ± 0.11 mg (Eq.GA)/g). HPLC-MS and UHPLC-HRMS results showcased that the main compounds in ROe were: rosmarinic acid, carnosic acid and carnosol. The evaluation of the in vitro antioxidant activity demonstrated a dose-dependent effect of ROe against several radicals and the capacity to reduce iron. Therefore, we demonstrated that topical application of the formulation containing ROe inhibited edema formation, myeloperoxidase activity, GSH depletion and maintained ferric reducing (FRAP) and ABTS scavenging abilities of the skin after UVB exposure.