Antitumor effects of Marginisporum crassissimum (Rhodophyceae), a marine red alga

Marginisporum crassissimum (Yendo) Ganesan, a marine red alga found in the ordinal coastal sea around Japan, revealed antitumor (antimetastatic) effec ts in vitro and in vivo. In in vitro experiments, extracts of this alga inh ibited not only the growth of several tumor cell lines, such as B16-BL6 (a mouse melanoma cell line), JYG-B (a mouse mammary carcinoma cell line) and KPL-1 (a human mammary carcinoma cell line), but also invasion of B16-BL6 c ells in a culture system. In in vivo experiments, the lung metastasis of B1 6-BL6 cells inoculated to the tail vein of B57BL/6J mice was inhibited by i ntraperitoneal administration of an extract from the alga, In addition, lif e prolongation of B57BL/6J mice inoculated with B16-BL6 cells was also obse rved by the intraperitoneal administration of the extract. An effective sub stance showing B16-BL6 growth inhibition in vitro was partially purified by filtration and hydrophobic column chromatography, and was revealed to be s ensitive to trypsin-digestion and heat-treatment. The molecular weight of t he substance was greater than 100 kDa. This is the first study demonstratin g antitumor (antimetastatic) effects of M. crassissimum. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.