Safety assessment of the fungal immunomodulatory protein from Ganoderma microsporum (GMI) derived from engineered Pichia pastoris: Genetic toxicology, a 13-week oral gavage toxicity study, and an embryo-fetal developmental toxicity study in Sprague-Dawley rats

Abstract

The 12.4 kDa fungal immunomodulatory protein from Ganoderma microsporum (GMI) has bioactivity in vitro and in vivo. This study assessed the safety of GMI derived from engineered Pichia pastoris in Sprague-Dawley rats as a dietary supplement and food ingredient by evaluating subchronic toxicity, teratology, and mutagenicity. The oral gavage administration of 10 mL GMI at 0, 50, 75, or 100 mg GMI/kg body weight/day assayed for 91 consecutive days showed no mortality or moribundity. There were no test article-related findings in animal observations/measurements: cageside observation, detailed clinical observations, body weights, feed consumption, ophthalmic examinations, functional observation battery, clinical chemistry, hematology, coagulations, urinalysis, or terminal necropsy (gross or histopathology findings) suggesting that GMI has no subchronic toxicity. The teratology toxicity study of pregnant female rats orally administered GMI at 0, 50, 75, or 100 mg/kg body weight/day throughout organogenesis (gestation date 6–18) showed no mortality, moribundity, and no test article-related finding to dam or fetus. GMI genotoxicity was not observed by mutagenicity studies of Salmonella typhimurium, in vitro chromosome aberrations, and an in vivo micronucleus test in mice. Overall, no observed-adverse-effect level (NOAEL) was determined for GMI based on the subchronic and teratology studies at 100 mg/kg body weight/day.