Composition and proposed structure of a water-soluble glycan from the Keumsa Sangwhang Mushroom (Phellinus linteus)

Phellinus linteus is a mushroom which has been prized in Korea for its medicinal properties since ancient times. A glycan preparation from this source has shown promise in experimental anti-tumour and metastasis studies, but the glycan has not been well characterized. In the present work, the glycan fraction of a hot water extract from P. linteus (Keumsa Sangwhang Mushroom, Korea) has been isolated following ammonium sulfate precipitation, dialysis/concentration and anion exchange chromatographic steps. Analyses for monosaccharide composition showed glucose and mannose to be the major constituents. Digestion of the glycan fraction with specific glycosidases and by linkage analysis allowed us to propose a core β(1–3) linked glucan heavily substituted via (1–6) links with β(1–3) linked mannose chains. Significant levels of galactose and xylose, present in the glycan fraction, may be associated with this glucomannan or not. These findings are consistent with the view that a core β(1–3)-linked glucan chain with β(1–6) branch points is a common feature of mushroom glycans possessing anti-tumour activity.