Structural characterization of an immunoenhancing cytotoxic heteroglycan isolated from an edible mushroom Calocybe indica var. APK2

A water-soluble polysaccharide of an edible mushroom Calocybe indica var. APK2 showed immunoenhancing (macrophage, splenocyte, thymocyte, and bone marrow activation) and cytotoxic activity toward HeLa cell lines and found to consist of D-glucose, D-galactose, and L-fucose in a molar ratio of nearly 3:1:1. On the basis of acid hydrolysis, methylation analysis, and NMR studies (H-1, C-13, DEPT-135, TOCSY, DQF-COSY, NOESY, ROESY, HMQC, and HMBC), the structure of the repeating unit of the fuco-galacto-glucan was established as: -> 3)-alpha-D-Galp-(1 -> 4)-beta-D-Glcp-(1 -> 6)-beta-D-Glcp-(1 -> 6)-beta-D-Glcp-(1 -> 6 up arrow 1 alpha-L-Fucp (C) 2011 Elsevier Ltd. All rights reserved.