Structural elucidation of an immunoenhancing heteroglycan isolated from Russula albonigra (Krombh.) Fr.

► A heteroglycan (PS-II) was isolated from the mushroom Russula albonigra (Krombh.) Fr. ► The PS-II consisted of glucose, galactose, manose, 2-OMe-fucose, and fucose. ► Its structure was established by chemical and 2D NMR studies. ► This molecule showed immunostimulatory property.