Abstract
Two water-insoluble glucans, U-3-N ([α]D +1.0°, 0.5 M sodium hydroxide) and U-3-AP1 ([α]D +2.5°, 1 M sodium hydroxide) were isolated from hot-water extract of the fruiting bodies of Yu er (Chinese name) (Auricularia sp.). U-3-N and U-3-AP1 were investigated by a combination of chemical and spectroscopic methods. The results indicated that U-3-N (molecular weight, 6.1×105) was similar to β-(1→6)-branched (1→3)-β-D-glucan (N-5P : molecular weight, 5.6×105) isolated from the alkaline extract of the fruiting bodies, and U-3-AP1 (molecular weight, 6.3×104) was β(1→6)-branched (1→3)-β-D-glucan containing β-(1→6)-linked D-glucopyranosyl residues. U-3-N showed potent antitumor activity against the solid form of sarcoma 180, although U-3-AP1 had little effect on the tumor.
