Neutral and acidic polysaccharides and their protein complexes were fractionated and purified from the brown seaweed umitoranoo (Sargassum thunbergii) by fractional extraction, iron-exchange chromatography, and gel filtration. Thirty-one polysaccharide fractions were obtained and tested for antitumor activity in mice with Ehrlich carcinoma transplanted i.p. Two of the fractions, GIV-A ([alpha]25D -127 degrees and mol. wt., 19,000) and GIV-B ([alpha]25D -110 degrees and mol. wt., 13,500) had such activity. On the basis of chemical and spectral analyses, these compounds were found to be a fucoidan or L-fucan containing approx. 30% sulfate ester groups per fucose residue, about 10% uronic acid, and less than 2% protein.

In the group receiving FIII-2-b, the percentages of splenic Thyl.2-, L3T4 and asialo GM1-positive cells were significantly increased as compared with the tumor-bearing mice treated with saline. Furthermore, the L3T4+/Lyt2+ ratio showed a tendency to increase, and the Lyt2+/Thy1.2+ ratio was markedly decreased. These results suggest that the antitumor effect of F III -2-b may be correlated with the changing pattern of the Thyl.2-, L3T4 and asialo GM1-positive cells.

Abstract. Blazein was isolated from mushroom (Agaricus blazei Murrill) and identified by Mass and 1 H-NMR as blazein. The effect of blazein on the DNA of human various cancer cells was investigated. DNA fragmentations by blazein to oligonucreosomal-sized fragments, a characteristic of apoptosis, were observed in the human lung LU99 and stomach KATO III cancer cells. The DNA fragmentations by blazein were observed from day 2 (KATO III cells) or day 3 (LU99 cells) after the addition of blazein to the culture cells. These findings suggest that growth inhibition by blazein results from the induction of apoptosis by the compound.