Lentinan samples

(13)-b-D-glucans containing 4.6-15.2 wt% proteins

coded as L-I1

L-I2

L-I3 and L-I4 (L-I) were isolated from four kinds of Lentinus edodes. These glucans were treated with acetone to remove the protein in order to obtain free protein glucans coded as LNP-I1

LNP-I2

LNP-I3 and LNP-I4 (LNP-I). The free-protein polysaccharides were sulfated to give derivatives (S-LNP-I) with degree of substitution (DS) from 0.4 to 0.8. The structural features and weight- average molecular weight (Mw) of the samples were investigated by using infrared spectroscopy

elemental analysis

13C-NMR

size exclusion chromatography combined with laser light scattering (SEC-LLS) and viscometry. The effects of structure and conformation of the polysaccharides on antitumor activities were assayed in vivo (Sarcoma 180 solid tumors) and in vitro (Sarcoma 180

HL-60

MCF-7 and Vero tumors). The results indicated that the predominant species of the samples L-I and LNP-I in 0.2 mol/L NaCl aqueous solution existed as triple-helical chains with high rigidity and in dimethyl sulfoxide (DMSO) as single-flexible chains. Interestingly

the antitumor activities of LNP-I are lower than those of the native glucans (L-I)

whereas their sulfated derivatives have higher inhibition ratio against Sarcoma 180 than LNP-I. The results reveal that the binding of protein

sulfated modification and the triple helix conformation are important factors in the enhancement of the antitumor activities of polysaccharides on the whole.