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

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.