Xylan is the second most abundant polysaccharide group in plants and has a wide variety of food and pharmaceutical applications. However, little information on the safety assessment of extracted xylan as dietary supplement is available. As part of a comprehensive toxicological assessment, this study examined the potential toxicity of xylan extracted from sugarcane bagasse by three genotoxicity studies (Ames test, in vivo mice bone marrow micronucleus test, and mice sperm abnormality test) and a teratogenicity study in rats. In the Ames test, xylan showed no mutagenic activity on histidine dependent strains of Salmonella typhimurium at concentrations up to 5000 μg/plate; results of the in vivo mice bone marrow micronucleus test and mice sperm abnormality test indicated no significant effect on sperm morphology and micronucleus rate of polychromatic erythrocytes in mice at doses up to 5 g/kg body weight. In the teratogenicity study, a total of 60 pregnant rats were exposed to 10, 5, and 2.5% xylan in diet, from gestation days 7 to 16, and the no-observed-adverse-effect levels (NOAEL) of xylan was determined to be 9.8 g/kg body weight. The safe dose of xylan for human was estimated to be 98 mg/kg/day (i.e., 6.86 g/day for a 70-kg person), using a 100-fold safety factor. Taken together, results of this study indicated that xylan is practically nontoxic in terms of potential dietary consumption by humans in food or as a dietary supplement.
Keywords: Genotoxicity; NOAEL; safety assessment; teratogenicity; xylan.