Cycloastragenol exerts protective effects against UVB irradiation in human dermal fibroblasts and HaCaT keratinocytes

Background: Cycloastragenol (CAG) is a triterpene aglycone of astragaloside IV that possesses various pharmacological actions including improving telomerase activity, inhibiting inflammation and cell proliferation, inducing apoptosis.Objective: CAG has also shown effect to significantly improve the appearance of aging skin but, its molecular mechanism of protective effect against UVB induced-damage have not been elucidated. We investigated the potential effect of CAG on UVB wrinkle promoting activities and skin-moisturizing effects in human dermal fibroblasts (HDF) and HaCaT keratinocytes.Methods: After UVB irradiation or H2O2 treatment, the levels of matrix metalloproteinases (MMPs) and ROS generation were measured in CAG-treated HDF cells. In addition, after UVB irradiation, hyaluronic acid and skin hydration factors (filaggrin and SPT) were also analyzed in CAG (0-0.5-1-2 & mu;M)-treated HDF and HaCaT cells.Results: We found that CAG caused a significant decrease in the levels of UVB-induced MMP-1, MMP-9, MMP-13 and ROS generation, also increased UVB-damaged Collagen I. We also noted that CAG increased cell viability and can regulate MMP-1, MMP-9, MMP-13and Collagen I in H2O2-damaged HDF cells. Moreover, we noticed that CAG effectively enhanced levels of hyaluronic acid and expression of skin hydration factors (filaggrin and serine palmitoyltransferase (SPT)) in UVB-damaged HDF and HaCaT cells. Conclusion: This is first report indicating that CAG can exhibit protective effect against UVB and H2O2induced damages and can contribute in maintenance of healthy skin.& COPY; 2023 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.