ENHANCING EFFECT OF POLYSACCHARIDES FROM AN EDIBLE BROWN ALGA, HIJIKIA FUSIFORME (HIJIKI), ON RELEASE OF TUMOR-NECROSIS-FACTOR-ALPHA FROM MACROPHAGES OF ENDOTOXIN-NONRESPONDER C3H HEJ MICE/

An enhancing activity for the release of tumor necrosis factor-alpha f rom macrophages of C3H/HeJ mice was detected in the hot water-soluble extract of an edible brown alga, Hijikia fusiforme (Hijiki in Japanese ). This activity was divided into the polysaccharide and nonpolysaccha ride fractions, with the former showing much higher activity than the latter. The active components in the polysaccharide fraction were furt her purified by ion-exchange column chromatography and gel permeation system of high-performance liquid chromatography; they were identified as polysaccharides with apparent molecular mass of about 2,000 and 70 kDa and were designated Hijiki-derived polysaccharides I and II (HPS- I and HPS-II), respectively. They also enhanced macrophage-dependent s uppression against the growth of EL-4 tumor cells in an in vitro cultu re experiment, with HPS-I exhibiting much higher immunologic activity than HPS-II. Furthermore, other comparative experiments confirmed that the immunoenhancing activities of polysaccharides from H. fusiforme a re associated with the functions of polysaccharides themselves, bur no r with the artificial activity induced by contaminated endotoxins. Som e biochemical properties of immunoenhancing polysaccharides were parti ally characterized, and the significance of-this finding is discussed from the viewpoint of the protective role of edible seaweeds against c arcinogenesis.