Protective Function of Malus baccata (L.) Borkh Methanol Extract against UVB/Hydrogen Peroxide-Induced Skin Aging via Inhibition of MAPK and NF-κB Signaling

Ultraviolet (UV) irradiation induces ROS production, which activates activator protein (AP)-1 and nuclear factor (NF)-κB signaling and downstream molecules, ultimately triggering the generation of matrix metalloproteinases (MMPs) and degradation of collagen. The aim of this study was to investigate the protective effect of methanol extract from Malus baccata (L.) Borkh (Mb-ME) against aging. DPPH and ABTS assays showed that Mb-ME had a significant antioxidant capacity. Flow cytometry results indicated that Mb-ME attenuated UVB and H₂O₂-stimulated apoptosis and reactive oxygen species (ROS) generation. RT-PCR analysis in HaCaT and HDF cells suggested that Mb-ME treatment blocked the expression of MMPs, COX-2, IL-1β, IL-6, HYALs, and p53 while promoting the levels of TGM1, FLG, HASs, Sirt1, and Col1A1. Mechanically, Mb-ME inhibited the phosphorylation of MAP kinases and NF-κB signaling. Overall, these results strongly suggest that Mb-ME can be developed as an antiaging therapy.