RESUMEN
Cordyceps is a fungus used as a traditional medicine in China, Japan, and Korea. Paecilomyces (P.) japonica is a new cordyceps that was recently cultivated on silkworm pupae in Korea. The present study evaluated the toxicological effects of P. japonica in rats. Forty rats were treated with oral doses of P. japonica (0, 20, 100, or 500 mg/kg/day) for 4 weeks. Twenty additional rats were treated with 0 or 500 mg/kg/day of P. japonica for 4 weeks and then maintained for 2 weeks without treatment. Clinical signs, body weight, food and water consumption, and organ weight as well as hematology, serum biochemistry, and histopathology data were examined. Body weight gain of the group treated with 500 mg/kg/day was significantly reduced. Microscopically, karyomegaly, single cell necrosis, and mitosis were observed in the renal tubular epithelium of all treated groups. In conclusion, P. japonica caused a reduction of body weight and renal injury in rats. The no observed adverse effect level (NOAEL) of P. japonica was less than 20 mg/kg/day.