Paecilomyces tenuipes, one of the commonly used Chinese medicinal fungus, has received
much attention over the world, which possesses various active compounds and biological activities.
However, little toxicological information is available. Therefore, the present study evaluated the
potential toxicity of aqueous and ethanol extracts of Paecilomyces tenuipes N45 via acute and
subchronic administration in mouse and rat, respectively. For improving the extraction rate of aqueous extract, response
surface methodology (RSM) was employed to optimize the extraction condition first in this paper. The obtained optimal
extract conditions were temperature 80 °C, liquid-solid ratio 50 mL·g-1 and time 3 h. In the acute toxicity test, aqueous
and ethanol extracts caused neither mortality nor toxicological signs, and the maximum tolerance dose was estimated over
15 g/kg. No mortality or adverse effects was observed in subchronic toxicity studies. No significant difference in
bodyweight, relative organ weight or hematological parameters was noted during the experiment. Comparing with nontreated
rats, ALT, K and BUN levels were changed in experimental group detecting via biochemical analysis. No
abnormality of internal organs was noted between treatment and control groups in gross and histopathological
examinations. Our present study suggested that the tolerance dose of the Paecilomyces tenuipes N45 extracts were more
than 15 g/kg and no-observed-adverse-effect level (NOAEL) of the extracts for both male and female rats after 90-day
adminstation. Additionally, the extracts may possess renal-protective and hepato-protective effects.