A mannofucogalactan, fomitellan A, with mitogneic effect from fruit bodies of Fomitella fraxinea (Imaz.)

Abstract

A heterogalactan, fomitellan A, was isolated from a 0.9% sodium chloride extract of the fruit bodies of Fomitella fraxinea by a combination of fractionation procedures, including precipitation with ethanol and chromatography on columns of DEAE-cellulose and Toyopearl HW 65F. On employing gel permeation-high performance liquid chromatograpy, fomitellan A exhibited a single peak with a molecular weight of 15 kDa. The results of methylation, and 1H and 13C NMR spectroscopic analyses indicated that the heterogalactan fomitellan A was a repeating unit (pentasaccharide) composed of a backbone with (1 → 6)-linked D-galactopyranosyl residues. Its C-2 atom position was substituted with disaccharide units of 3-O-D-mannopyranosyl-L-fucopyranosyl residues. The fucomannaogalactan (fomitellan A) from Fomitella fraxinea showed pronounced immunostimulating activity in an in vitro lymphocytes proliferation assay.