Bazi Bushen capsule alleviates skin photoaging by targeting the KEAP1–NRF2 pathway

BACKGROUND: Photoaging is a prevalent and multifaceted form of exogenous skin aging. A comprehensive approach to preventing photoaging may yield greater benefits compared to a single intervention. PURPOSE: This study aimed to investigate the pharmacological effects and underlying mechanism of the compound medicine Bazi Bushen (BZBS) capsule in combating skin photoaging. STUDY: Experiments were conducted to verify the therapeutic effect of BZBS in treating skin photoaging. Potential compounds and targets were screened through network pharmacology analysis and validated using both in vitro and in vivo experiments. METHODS: Laser Doppler flow imaging, histopathological examination, biochemical evaluation, western blot (WB), real-time reverse transcription-polymerase chain reaction (RT-qPCR) and immunofluorescence staining were employed to evaluate the therapeutic effects of BZBS in photoaging mice. Network pharmacology analysis, molecular docking and bio-layer interferometry (BLI) were utilized to predict the key targets and pathways. The role of key compounds on the kelch-like ECH-associated protein 1 (KEAP1) -nuclear factor erythroid 2-related factor 2 (NRF2) pathway in photodamaged skin cells was further validated by antioxidant response element-luciferase (ARE-luc) reporter system, immunofluorescence staining, WB and RT-qPCR. RESULTS: BZBS and β-Nicotinamide Mononucleotide (NMN) effectively mitigated structural and functional degeneration caused by ultraviolet radiation (UVR) of the mice, promoted hair follicle growth, and suppressed inflammatory cell infiltration. Mechanistically, BZBS enhanced the expression of NRF2 both in vivo and in vitro, thereby alleviating oxidative stress and associated aging phenotypes. Furthermore, verbascoside and epimedin A-key components of BZBS-directly bound to KEAP1, inhibiting KEAP1-mediated degradation of NRF2 and consequently alleviating oxidative senescence. CONCLUSION: This study demonstrates the therapeutic potential of BZBS in combating skin photoaging by modulating the KEAP1-NRF2 pathway. Notably, we identified two novel natural compounds in BZBS-verbascoside and epimedin A-that specifically target and bind to KEAP1. These findings offer a promising therapeutic strategy for alleviating skin photoaging through traditional Chinese medicine and provide valuable insights into the anti-aging mechanisms of composite drugs.