AIMS OF THE STUDY: The present study aims to establish safety profile for the consumption of cultivated fruiting body of O. sinensis (FBOS) by 28-days sub-acute toxicity study in Sprague Dawley rats.
MATERIALS AND METHODS: Rats were orally administered with cultivated FBOS at three graded doses (250, 500 and 1000mg/kg), once daily for 28 consecutive days. Control group received distilled water. General observations (gross behavioral changes and toxic symptoms) and body weight of each animal were monitored daily. Haematological, serum biochemical and histopathological analysis were carried out at the end of the experiment (Day 29).
RESULTS: No behavioral changes, toxic symptoms or death was observed in rats throughout the dosing period. Cultivated FBOS treatment up to 1000mg/kg did not cause any adverse effect on the growth of the animals. Results from haematology and serum biochemistry revealed no toxic effect following cultivated FBOS treatment at three graded doses for 28 days. In addition, no treatment related histopathological changes were noted in heart, spleen, kidney, lung and liver of the animals.
CONCLUSION: The present study revealed that oral administration of cultivated FBOS for 28 days, at dosage up to 1000mg/kg did not pose toxicological concern in rats. Therefore, the no-observed-adverse-effect level (NOAEL) dose of cultivated FBOS in 28-days subacute toxicity study is higher than 1000mg/kg.
MATERIALS AND METHODS: Eighty pregnant SD female rats were used in this study for three treatment groups and a control group, each consisting of 20 pregnant female rats. Three doses of 850mg/kg/day (Low-dose), 1700mg/kg/day (Mid-dose) and 3400mg/kg/day (High-dose) were selected for the study, whereas 10mL/kg distilled water was served as the control. Examinations were conducted on pregnant rats and fetuses respects to mortality, body weight, body weights gains, food consumption and clinical observations. The pregnant females were gross necropsied on G20, followed by maternal and fetus examination, to evaluate the teratogenicity, reproductive and developmental performance of L. rhinocerotis mycelium.
RESULTS: Results showed that no L. rhinocerotis mycelium-related animal death and abnormal clinical sign were noted. No statistical differences were noted in maternal mean body weight and maternal mean body weight gains. Some animals in the high-dose group appeared audible respiration due to dosing accident, it resulted in lower food consumption but not relevant to L. rhinocerotis mycelium treatment. In maternal gross necropsy, no L. rhinocerotis mycelium-related gross lesion was noted. In maternal examination, parameters of gravid uterus weight, implantation number, corpora lutea number, litter size, live or dead fetal number, male or female fetus number, resorption number, fetal sex ratio (M/F), pre-implantation loss and post-implantation loss were all within the normal reference ranges and showed no significant difference when compared to the control group. In fetus examination, including external, visceral and skeletal evaluations, there were no significant changes between any of the L. rhinocerotis mycelium treated groups and the control group.
CONCLUSIONS: Based on the study results, the no-observable-adverse-effect level (NOAEL) for pregnant female rats under the conditions of this study was 3400mg/kg/day.