SELECTIVE CYTOTOXICITY OF MARINE-ALGAE EXTRACTS TO SEVERAL HUMAN LEUKEMIC-CELL LINES

Extracts from 8 species of marine algae which showed selective cytotox icity in our previous screening program, were further examined for cyt otoxic spectra to five human leukemic cell lines. The extract from a r ed alga, Amphiroa zonata exhibited strong cytotoxicity to all human le ukemic cell lines tested and murine leukemic cells L1210 at the final concentrations from 15 to 375 mu g ml(-1). Then the cytotoxicity was n ot found in normal human fibroblast HDF and murine normal cells NIH-3T 3. The active extract fraction from this alga was soluble in higher po lar organic solvents and water and heat-stable. The extract from a bro wn alga Dilophus okamurae with weak selective cytotoxic activity to 1. 1210 cells exhibited not only strong cytotoxicity to L1210, but also t o human leukemic cells, HL60 and MOLT-4 at 50 mu g ml(-1). While, the extract from a green alga, Cladophoropsis vaucheriaeformis with most s elective cytotoxic activity, did not show cytotoxicity to any human le ukemic cell lines tested at 50 mu g ml(-1) However, this extract showe d strong cytotoxicity to two human leukemic cell lines and NIH-3T3 at 100 mu g ml(-1) Thus, it was considered that a red alga, Amphiroa zona ta might be suitable natural source for development of anti-cancer age nts without side-effect.