Toxicological evaluation of Disialyllacto-N-neotetraose disodium salt

Human milk oligosaccharides (HMOs) have gained attention owing to their diverse composition and potential functions, including prebiotic effects, pathogen protection, immune system development, and cognitive development. We produced Disialyllacto-N-neotetraose (DSLNnT) disodium salt, an HMO with beneficial effects such as anti-inflammatory activity, using a unique one-pot enzyme reaction system. However, its safety remains unclear. HMO safety is critical for commercial use in food and pharmaceutical industries. We evaluated the safety of DSLNnT disodium salt using genotoxicity tests (bacterial reverse mutation, in vitro mammalian chromosomal aberration, and in vivo micronucleus tests), a 28-day repeated-dose oral toxicity dose range-finding study in rats, and a 90-day repeated-dose oral toxicity study in rats. DSLNnT disodium salt showed no genotoxic effects in the three genotoxicity tests. In the 90-day repeated-dose oral toxicity study, no DSLNnT disodium salt-related effects were observed in clinical signs, body weight, food intake, water intake, hematology, clinical chemistry, organ weight, necropsy, or histopathological findings at concentrations up to 2,000 mg/kg/day. The no-observed-adverse-effect level of DSLNnT disodium salt was 2,000 mg/kg/day for males and females. These results provide strong evidence that DSLNnT disodium salt is safe for consumption, supporting its potential commercial application as a functional ingredient in food and pharmaceutical industries.