Ganoderic Acid A Reverses Ultraviolet B Induced Hyperpigmentation via Multi-Targeted Regulation of Mitochondrial Homeostasis and Inflammation

BACKGROUND: Conventional tyrosinase (TYR) inhibitors irritate skin and trigger rebound pigmentation, necessitating safer and more effective depigmenting agents. METHODS: Biocompatibility was assessed by cell viability. Melanin content and TYR activity were measured spectrophotometrically. Reactive oxygen species (ROS), adenosine triphosphate (ATP), and inflammatory cytokines were detected by fluorescence, luminescence, and ELISA. Western blot and RT-qPCR assessed oxidative stress, inflammatory, and melanogenic targets. Molecular docking simulated Ganoderic Acid A (GAA) interactions with key proteins. RESULTS: GAA exhibits good biocompatibility, inhibits melanin synthesis and TYR activity in B16-F10 cells, and reverses ultraviolet B-induced pigmentation. Mechanistically, GAA restores mitochondrial homeostasis by scavenging ROS, replenishing ATP, activating the nuclear factor erythroid 2-related factor 2 (Nrf2) axis, and inhibiting nuclear factor kappa-B (NF-κB) and cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) to regulate the inflammatory microenvironment. This synergistic regulation inhibits the mitogen-activated protein kinase (MAPK) signaling pathway and down-regulates the microphthalmia-associated transcription factor (MITF) transcriptional network and the expression of TYR, tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2). CONCLUSION: GAA eliminates ultraviolet B-induced hyperpigmentation through a multi-target mechanism of mitochondrial repair, inflammation inhibition, and direct binding to tyrosinase, and is a potential natural candidate drug for the treatment of skin diseases.