Studies on Action Mechanism of Acrocidal Activity of Extracts of Pharbitis purpurea Seeds against Tetranychus cinnabarinus

Abstract

AbstractAction mechanism of isolation fraction 8 of petroleum ether extract of Pharbitis purpurea seeds against Tetranychus cinnabarinus was investigated. The acaricidal activities of isolation fraction 8 were measured by Slide-dip and Leaf-residue, and several kinds of important enzymes in T. cinnabarinus treated with isolation fraction 8 were tested. The ultrastructure of T. cinnabarinus treated by isolation fraction 8 was observed through transmission electron microscope (TEM). The isolation fraction 8 had strongly acaricidal activities against adult and egg of T. cinnabarinus, the LC50 value were 0.4686 mg/ml and 1.2212 mg/ml, the LC90 value were 2.5935 mg/ml and 3.1234 mg/ml. The activities of glutathione-S-transferase in T. cinnabarinus were strongly induced, but the activities of acetylcholinease, monoamine oxidase and Ca2+-ATPase were restrained after treating with isolation fraction 8. The result suggested that isolation fraction 8 of P. purpurea seeds was effective against T. cinnabarinus, which may be the cause the transmit block of nerve in mites. Observation under TEM revealed that cuticle, muscular filament, nuclear membrane, mitochondria and endoplasmic reticulum were ruptured. The result from the experiment indicated that the discovery had some exploiter value for making full use of P. purpurea seeds as new resources of botanical acaricide.KeywordsPharbitis purpureaTetranychus cinnabarinusglutathione-Stransferaseacetylcholineasemonoamine oxidaseCa2+-ATPasetransmission electron microscope