Safety assessment of mushroom β-glucan: Subchronic toxicity in rodents and mutagenicity studies

Mushroom β-glucan, a polymer of β-(1,3/1,6)-glucan, has been claimed for its health benefits. The objective of this study was to assess the safety in-use of mushroom β-glucan as dietary supplement and food ingredient. Hence, a subchronic toxicity and mutagenicity studies were conducted. In the subchronic toxicity study, Sprague Dawley rats (12/sex/group) were administered (gavage) mushroom β-glucan at dose levels of 0, 500, 1000 and 2000 mg/kg body weight (bw)/day for 90 days. As compared to control group, administration of β-glucan did not result in any toxicologically significant treatment-related changes in clinical observations, ophthalmic examinations, body weights, body weight gains, feed consumption, and organ weights. No adverse effects of the β-glucan on the hematology, serum chemistry parameters, urinalysis or terminal necropsy (gross or histopathology findings) were noted. The results of mutagenicity studies as evaluated by gene mutations in Salmonella typhimurium, in vitro chromosome aberrations and in vivo micronucleus test in mouse did not reveal any genotoxicity of β-glucan. Based on the subchronic study, the no observed-adverse-effect level (NOAEL) for mushroom β-glucan was determined as 2000 mg/kg bw/day, the highest dose tested.