Chitosan is known to have antibacterial, antitumorogenic, hypolipidemic and immunopotentiating activities, hence finding diverse uses as a component in varying functional foodstuffs. However, some investigators reported it caused mineral absorption ingibition and excess coagulation. From the chemical viewpoint, conventional chitosans are high-molecule polymers lacking water solubility, which could be related with their possible toxicity. A newly developed low-molecule water soluble chitosan is thought to have low toxicity compared to conventional chitosans. But no investigation was carried out to evaluate its toxicity.
In this study, a 28-day subacute oral toxicity study of the water-soluble chitosan was performed in Sparague-Dawley rats of both sexes. Each 36 male rats were orally administered with 500, 1,000 and 2,000 mg/kg/day for 28 consecutive days, respectively.
Clinical parameters (growth rate, feed and water consumption, daily inspection, urine analysis) during the 28 days indicated the water-soluble chitosan did not induce any abnormal changes.
There were no abnormal findings due to the administration of the test substance in gross and microscopic findings. We had not found alternation in absolute and relative organ weight between the control and treated groups, with only exception in the liver but lacking close-dependency. The results of hematology and serum biochemistry examination revealed that no treatment related changes were between control and all dose groups.
In conclusion, it was suggested that subacute toxicity of the water-soluble chitosan was low and the no-observed adverse effect level was considered to be over 2,000 mg/kg in rats.
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