Investigation of Polysaccharides from Morchella esculenta Cap and Stipe: Structural Characterization and Antioxidant Activities in a Caenorhabditis elegans Model

Abstract Morchella esculenta is a valuable edible and medicinal mushroom. Investigation and comparison of polysaccharides from various parts of M. esculenta are still deficient, especially the stipes are mostly discarded, causing resource wastage. This study investigated structural characteristics and antioxidant activities of polysaccharides from the cap (MECP) and stipe (MESP) of M. esculenta. MECP and MESP were both composed of glucose, mannose, ribose, and glucuronic acid but in different proportions. MECP and MESP possessed polysaccharide characteristic functional groups and dense sheet-like structures, which can effectively scavenge free radicals (ABTS+, DPPH) and had strong reducing power. Under hydrogen peroxide stress, MECP and MESP enhanced the survival rate and time of Caenorhabditis elegans by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and up-regulating gst-4, sod-3, and gsh-px gene expression, thereby resisting oxidative stress and aging process. These findings provided certain valuable insights for further development and utilization of M. esculenta cap and stipe.