Mycochemical study of polysaccharides from the edible mushroom Cortinarius caperatus (Gypsy mushroom)

Among basidiomycete molecules, cell wall polysaccharides have been recognized as a major class of bioactive constituents. [1] They are safe molecules and they have a wide spectrum of biological activities, such as immunostimulatory and antioxidant, therefore they possess a prominent role in health benefits coming from mushroom consumption. These properties make mushroom polysaccharides potential candidates for nutraceutical applications and bioactive ingredients production. [2] Fractionation of the hot aqueous extract of Cortinarius caperatus led to isolation of two fractions characterized by spectroscopic analyses (1H-NMR, 13C-NMR, DEPT, 1H-1H COSY, DQCOSY, TOCSY, HSQC, HMBC and HMQC), mass spectrometry (EI-MS, ESI-MS), infrared spectroscopy (FT-IR), chemical reactions of hydrolysis and derivatization followed by GC and HPLC analyses. [3] This mycochemical study revealed a water-soluble fraction characterized as a β-(16)-D-glucan, whose presence inside C. caperatus has never, to the best of our knowledge, been reported before. Moreover, a water insoluble fraction purified has been characterized as a branched , (1→6) glucan which structure is assumed to be: [→6)-β-D-Glcp(1→6)]4-α-D-Glcp(1→4)-β-D-Glcp(1→ 6 ↑ 1 α-D-Glcp The antioxidant activity of the soluble polysaccharide fraction has been evaluated as radical-scavenging activity with the DPPH test, the β-(16)-D-glucan showed significative antioxidant activity.