Purification, characterization and protective effects on UVB‐induced photoaging in zebrafish of Pleurotus citrinopileatus polysaccharide PCP‐2

Abstract BACKGROUND Polysaccharides from Pleurotus citrinopileatus exhibit diverse bioactivities, yet their efficacy against ultraviolet B (UVB)‐induced photoaging remains unexplored. This study aimed to purify and characterize a specific PCP and assess its protective effects using a UVB‐induced zebrafish model. RESULTS A polysaccharide, designated as PCP‐2, was isolated from P. citrinopileatus through hot‐water extraction, ultrafiltration and chromatography. PCP‐2 is a galactoglucan with a molecular weight of 1.52 × 10 6 Da, predominantly composed of 1,4‐linked glucopyranosyl and 1,4,6‐linked galactopyranosyl residues. In UVB‐exposed zebrafish, PCP‐2 administration resulted in a significant reduction of reactive oxygen species and malondialdehyde levels, alongside enhanced activities of antioxidant enzymes, including superoxide dismutase, catalase and glutathione peroxidase. Additionally, PCP‐2 inhibited apoptosis by upregulating Bcl‐2 expression and downregulating caspase‐3. It also attenuated cellular senescence, as indicated by decreased β ‐galactosidase activity and increased telomerase activity. Moreover, PCP‐2 promoted the synthesis of type I and III collagen by suppressing matrix metalloproteinases MMP‐1 and MMP‐3 and reduced melanin production through the downregulation of tyrosinase expression. Mechanistic studies suggested that these protective effects are mediated via activation of the Nrf2/HO‐1 signaling pathway. CONCLUSION PCP‐2 from P. citrinopileatus effectively mitigates UVB‐induced photoaging, primarily by activating the Nrf2/HO‐1 pathway. These findings suggest PCP‐2's potential as an anti‐photoaging agent in both food and pharmaceutical industries. © 2025 Society of Chemical Industry.