Rosa rugosa Root Extract as a Functional Food Ingredient, Mitigating UVB ‐Induced Skin Aging Through MAPK / AP ‐1 and AGE ‐ RAGE Pathway Modulation

ABSTRACT Rosa rugosa root extract (RR‐r) has been used in East Asian medicine to treat metabolic disorders, including diabetes and alcohol‐induced liver toxicity. Although RR‐r has been demonstrated to exhibit anti‐inflammatory and antioxidant properties, further research is required to elucidate its protective effects against ultraviolet B (UVB)‐induced skin photoaging. In this study, high‐performance liquid chromatography was used to identify rutin as the major indicator compound of RR‐r. The photoprotective activity of RR‐r was evaluated using a mouse model of UVB‐induced skin damage. Mice were orally administered RR‐r (100 or 200 mg/kg) for 8 weeks during UVB irradiation. RR‐r significantly alleviated UVB‐induced wrinkle formation, epidermal thickening, and collagen fiber degradation. The assessment of skin morphology and hydration was conducted through the use of histological staining (H&E and Masson's trichrome), wrinkle and moisture analysis, and enzyme‐linked immunosorbent assay quantification of hyaluronic acid. Western blotting revealed that RR‐r increased pro‐collagen type I, tissue inhibitor of metalloproteinases 1, hyaluronan, collagen‐1 while reducing the matrix metalloproteinase family, hyaluronidase 1 and hyaluronidase 2. A further mechanistic analysis revealed that RR‐r inhibited UVB‐induced phosphorylation of mitogen‐activated protein kinase pathway components and downstream activator protein‐1 factors. Furthermore, RR‐r significantly suppressed UVB‐induced accumulation of advanced glycation end products (AGEs) and expression of their receptor, RAGE. Collectively, these findings demonstrate that oral RR‐r effectively protects against UVB‐induced photoaging by regulating wrinkle‐related proteins, enhancing skin hydration, and modulating MAPK/AP‐1 and AGE‐RAGE signaling. Thus, RR‐r may represent a promising natural candidate for skin anti‐aging interventions.