Antitumor effect of seaweeds. IV. Enhancement of antitumor activity by sulfation of a crude fucoidan fraction from Sargassum kjellmanianum
Yamamoto, I.; Takahashi, M.; Suzuki, T.; Seino, H.; Mori, H.
Japanese Journal of Experimental Medicine 54(4): 143-151
1984
ISSN/ISBN: 0021-5031 PMID: 6513098 Document Number: 225015
An antitumor aqueous extract from a brown marine alga S. kjellmanianum (Hahakimoku in Japanese) was reported. Although the extract was effective in the in vivo growth inhibition of the implanted Sarcoma-180 cells, it was not effective against L-1210-bearing mice. An attempt was made to obtain a polysaccharide fraction with antitumor activity against L-1210 leukemia from this alga, on the assumption that the main active substance may be sulfated polysaccharide, especially fucoidan which is mainly composed of L-fucose and ester sulfate. Two kinds of polysaccharide fractions (SKCF and SKCF-F), which contained L-fucose and ester sulfate in the amount of 12.6% and 15.4%, 23.5% and 17.2%, respectively, were first prepared starting with extraction with cold-hydrochloric acid, and their antitumor activity was examined. They were not effective. Sulfation of SKCF was then carried out. The resulting sulfate (sulfated SKCF) was observed to contain nearly 50% more ester sulfate than in SKCF and to be effective against L-1210 leukemia showing an ILS value of 26%. Mechanisms of antitumor action of this sulfate were discussed from the viewpoints of negativity of ester sulfate and of activation of host-mediated immune response as observed in antitumor polysaccharide preparations from other sources.