Safety evaluation of water extract of Gastrodia elata Blume: Genotoxicity and 28-day oral toxicity studies.

Water extract of Gastrodia elata Blume (WGE) has great potential as an anti-depressant and could be developed as a functional food. This study aims to assess the safety of WGE using in vitro and in vivo genotoxicity assays and a 28-day oral toxicity study. Results from a bacterial reverse mutation assay (Ames test) using five Salmonella typhimurium strains (TA98, TA100, TA102, TA1535, and TA1537) with or without metabolic activation (S9 system) showed that WGE did not induce mutagenicity. Nor did it induce clastogenic effects in Chinese hamster ovary (CHO-K1) cells with or without S9 activation. Moreover, WGE did not affect the proportion of immature to total erythrocytes or the number of micronuclei in immature erythrocytes of ICR mice. Finally, a dose-dependent 28-day repeated dose toxicity assessment of WGE (2040, 4080, and 8065 mg/kg body weight, p.o.) in mice revealed no adverse effects on behavior, mortality, body weight, haematology, clinical biochemistry, or organ weight. No toxicopathologic lesions were detected following administration of high-dose WGE compared to controls. In conclusion, WGE has no significant mutagenic or toxic properties, and the no-observed-adverse-effect level (NOAEL) of WGE can be defined as at least 8065 mg/kg/day orally for 28 days for male and female mice.