Safety assessment of the Polypodium feei root extract: Acute and subchronic studies

This study was performed to assess the safety of the oral acute and subchronic administration of Polypodium feei root extract through acute and subchronic studies in mice and rats, respectively. In the acute toxicity treatment, mice were grouped according to the dose (1000, 2000, 4000 and 5000 mg/kg, b.w) and were observed for mortality and toxicity signs for 14 days. In the subchronic treatment, there were six groups of rats (female and male), a control group, three test groups (100, 400, and 800 mg/kg, b.w), and two satellite groups (control satellite and satellite 800 mg/kg groups). The three test groups received the extract orally once daily for 90 days. No animals in the acute and subchronic treatment groups showed mortality and any signs of toxicity, with no significant difference in the body weight and organ index compared to the control. The LD(50) of the extract was estimated to be higher than 5000 mg/kg, therefore regarded as practically non-toxic. The haematological profiles did not significantly change on exposure to the extract for 90 days, except the platelet count in the female animals which significantly decreased in animals treated with 400 and 800 mg/kg, returning to normal after 28 days of recovery. The 800 mg/kg dose significantly increased the urea concentration and induced lesions in the stomachs of female animals. However, this undesirable effect on the kidney was not strong, as the creatinine concentration remained in the normal limits, and the histopathological observations showed no alteration in the kidney tissues. No significant morphological alterations in organs were observed, only minor lesions in the liver. These results indicate that the P. feei root extract is safe for use as herbal medicine and recommended at doses lower than 400 mg/kg.