Abstract: Deoxypodophyllotoxin is the main insecticidal composition in Sabina vulgaris Ant., an insecticidal plant. In order to study its insecticidal mechanism, the effect of deoxypodophyllotoxin on activities of carboxyl esterases (CarE), phosphatase, glutathione S-transferase (GSTs) and microsomal mixed function oxidase (MFO) in larvae of Mythimna separata Walker were assayed. The results showed that the activities of CarE in tested larvae had no distinct change; with extending of treatment time, the activities of acid phosphatase (ACP) in tested larvae were gradually inhibited by deoxypodophyllotoxin; the change of alkaline phosphatase (AKP) activity was very complex; the activity of GSTs had no distinct change in 12 h, was inhibited in 24 h, but was activated in 36 h; the O-demethylase activity of cytochrome P450 was inhibited by deoxypodophyllotoxin.

Key words: Mythimna separata, Sabina vulgaris, deoxypodophyllotoxin, metabolizing enzymes, inhibition