Genotoxicity testing of low molecular weight fucoidan from brown seaweeds

Fucoidan extracts from brown seaweed have anticoagulant, antithrombotic, and antiviral activities. Low molecular weight fucoidan (LMF) obtained by acid hydrolysis of high molecular weight fucoidan showed more favorable bioactivity. Despite extensive work on LMF bioactivities, detailed studies on the genotoxicity of LMF have not been conducted. As part of a safety evaluation, the potential genotoxicity of LMF was evaluated using a standard battery of tests (bacterial reverse mutation assay, chromosomal aberrations assay, and mouse micronucleus assay). The LMF was determined not to be genotoxic under the conditions of the reverse mutation assay, chromosomal aberrations assay, or mouse micronucleus assay. In a reverse mutation assay using four Salmonella typhimurium strains and Escherichia coli, LMF did not increase the number of revertant colonies in any tester strain regardless of metabolic activation by S9 mix, and did not cause chromosomal aberration in short tests with the S9 mix or in the continuous (24 h) test. A bone marrow micronucleus test in ICR mice dosed by oral gavage at doses up to 2000 mg/kg body weight/day showed no significant or dose-dependent increases in the frequency of micronucleated polychromatic erythrocytes. Use of LMF is presently expected to be safe, as anticipated intake is small compared to doses administered in the genotoxicity assays and may prove to be a useful bioactive agent after further toxicity research.