Comparative Profiling of Free and Bound Polyphenols from Five Wild Boletus edulis Varieties: Antioxidant Activity and Longevity-Regulating Effects in Caenorhabditis elegans

Abstract Boletus edulis is rich in phenolic compounds, but the composition and bioactivity of its free and bound polyphenols remain insufficiently compared. In this study, free and bound polyphenols from five wild edible Boletus edulis samples were profiled, and their antioxidant and longevity-regulating effects were evaluated in vitro and in Caenorhabditis elegans. A total of 27 phenolic compounds were identified, showing marked variation among samples and fractions. The free fraction of Leccinum rugosiceps (LrS-F) and the bound fraction of Boletus edulis Bull.: Fr. (BeB-B) showed the best overall antioxidant and lifespan-promoting performance, reducing reactive oxygen species and malondialdehyde levels, enhancing superoxide dismutase and catalase activities, and extending nematode lifespan. Mutant-based, transcriptional, and protein-level analyses indicated that these effects involved daf-16-dependent antioxidant regulation and additional JNK-1/SKN-1-related stress responses. These findings highlight B. edulis polyphenols as natural antioxidant resources with potential longevity-regulating activity.