The biological effects of Rosa rugosa extract on keratinocyte differentiation and enhancement of skin barrier function

We investigated the biological activity of Rosa rugosa (R. rugosa) extract in human epidermal keratinocytes. To assess the antioxidant capacity of the extract, various concentrations (0.1, 0.5, 1, 5, 10, 50 mg/ml) were tested against DPPH and ABTS free radicals. The results showed antioxidant activities of 45% at 5 mg/ml, 60% at 10 mg/ml, and 82% at 50 mg/ml. Cell toxicity experiments using human keratinocytes revealed no cytotoxicity up to 10 μg/ml, and the cells exhibited a differentiated morphology. We confirmed the efficacy of the extract in keratinocytes, with a significant increase in the expression of keratinocyte differentiation factors Keratin (KRT)1 and KRT10. Moreover, the expression of genes related to skin barrier function, including Filaggrin (FLG), Involucrin (IVL), Loricrin (LOR), and Claudin1 (CLDN1), significantly increased. In an in vitro atopic model experiment treating human keratinocytes with Interleukin (IL)-4/IL-13, the R. rugosa extract maintained the expression of FLG protein. Overall, R. rugosa demonstrated high antioxidant activity and was found to be a safe material for human keratinocytes. Furthermore, it induced keratinocyte differentiation, particularly increasing the expression of FLG, IVL, LOR, and CLDN1, which are components of the skin barrier. While additional research is needed to validate these experimental results, R. rugosa extract holds promise as a novel ingredient for the development of cosmetics or pharmaceuticals that could alleviate inflammatory skin conditions such as atopic dermatitis or psoriasis.