Effects of Stigmasterol to Activities of Several Enzymes of Tetranychus cinnabarinus

Abstract

Abstract. The acaricidal activity of stigmasterol was carried out on the Tetranychus cinnabarinus, using the slide dip technique. Here the female adult mites were treated by the Stigmasterol extracted from Inula japonica. Bioassayguided purification of the 12th fraction had higher activity against the T. cinnabarinus, Gas chromatography-mass spectrometry (GC/MS) demonstrated that the chemical composition of the active fraction 12th sample was mainly composed of Stigmasterol. That had not been reported before. And the acaricidal mechanism of Stigmasterol to T. cinnabarinus is unknown. Our results showed that the nervous symptoms of the T. cinnabarinus in response to the Stigmasterol. The protein content, the acetylcholine esterase (AChE) activity, the Calcium enzyme ATP (Ca2+-ATPase) activity and Sodium enzyme ATP (Na+-ATPase) activity of the mites treated with Stigmasterol were assayed. The results showed that the protein content and the activity of AchE in the T. cinnabarinus treated with the Stigmasterol were increased. The activity of Ca2+-ATPase and Na+-ATPase were induced by the Stigmasterol. The effects of the T. cinnabarinus indicated that the central nervous system was the main target of Stigmasterol. The long time over excitation caused the treated mites to die.