Abstract: The contact toxicity of deoxypodophyllotoxin to newly-hatched Periplaneta Americana larvae was tested with the method of drug film, and its effects on the in vitro activities of AChE and ATPase in central nerve system of adult P. Americana were investigated.  The results indicated that deoxypodophyllotoxin exhibited high toxicity against P. Americana larvae, and its LC₅₀ values were 26.26, 4.68, 1.51, and 0.62 μg/cm² at 24, 48, 72, and 96 h of exposure time, respectively. Though deoxypodophyllotoxin did not affect the activity of AChE, it inhibited Na⁺-K⁺-ATPase in dose-dependent manner at the range of 5-625 μmol/L concentration and the IC₅₀ was 44.9 μmol/L. Deoxypodophyllotoxin showed activating effect at lower concentration while inhibitory effect at higher concentration on Ca²⁺-Mg²⁺-ATPase. The results suggest that AChE is not target of deoxypodophyllotoxin, while ATPase may be one of important targets of deoxypodophyllotoxin.

Key words: Periplaneta americana, deoxypodophyllotoxin, contact toxicity, AChE, ATPase, enzyme activity