Structure-function relationship of antitumor .BETA.-1,3-glucan obtained from matted mycelium of cultured Grifola frondosa.

Abstract

The structure-function relationship of the antitumor 6-branched β-1, 3-glucan (grifolan NMF-5N) extracted from the matted mycelium of Grifola frondosa was examined by using various chemical modification procedures (periodate oxidation, Smith degradation, and enzymic hydrolysis). The antitumor activity of grifolan NMF-5N was not lowered by periodate oxidation. Partial removal of branches by mild hydrolysis did not affect the activity. However, the linear β-1, 3-glucan obtained by Smith degradation lacked antitumor activity. From the results of enzymic hydrolysis of grifolan NMF-5N, this glucan contains a β-1, 3-glucanase-resistant core structure. The core structure is present randomly in this glucan, and does not itself show antitumor activity. These results suggest that some of the branches at C-6 in grifolan NMF-5N are important for the antitumor activity, and that the activity requires a relatively high molecular weight.