Inhibition of Enzymes from the Tobacco Cutworm by Chiordimeform and Clerodin

Mode of Action of Antifeeding Compounds in the Larvae of the Tobacco Cutworm, Spodoptera litura (F.) (Lepidoptera: Noctuidae) (Part 5)

Abstract

Chlordimeform hydrochloride and clerodin showed no inhibitory activity against acetyl-cholinesterase (AChE) from the heads of the 5th instar larvae of the tobacco cutworm when measured radiometrically in vitro. In vivo anti-AChE estimation using a leaf disc method also showed that both antifeeding compounds had no anti-AChE activity. Monoamine oxidase (MAO) activity was not observed in the homogenate of the insect heads. Therefore, it is doubtful that the symptoms caused by the antifeeding compounds are derived from the inhibition of AChE and MAO.