Study On Biological Activity Of The Extracts Of Inula Britanica Against Tetranychus Cinnabarinus

Inula britanica was investigated for its acarcidal activity against Tetranychus cinnabarinus, a serious pest of many crops including fruit trees in China. Action mechanism of effective substance of Inula britanica against T. cinnabarinus was also investigated. Acaricidal activities of 24 plants extracts by 3 solvent against Tetranychus cinnabarinus were measured in laboratory using slide-dip method. Our results showed that the mortality from petroleum ether extract of Inula britanica which showed significantly higher acaricidal activities than the other ones at a concentration of 2 mg/mL. The toxicosis symptom of T. cinnabarinus was observed. Symptoms such as convulsions, excitement, atrophy, et al. were observed. Liquid-liquid distribution was used to separate and purify active matter. The results indicated that petroleum ether extract of Inula britanica had highest adjusted mortalities of 91.2% for female mite. The silica gel column was used to separate and purify active constitutes of the crude purified extracts of petroleum ether. A total of 38 bands were seen by TLC analysis. There were 17 fractions with 24h corrected mortality over 50%. The compounds such as Lupeol,Stigmasterol,Ethyl palmitate, et al.were found in the bioactive fraction by gas chromatography /mass spectrometry (GC/MS). Action mechanism of Lupeol, Stigmasterol, Ethyl palmitate from f petroleum ether extract of Inula britanica against T. cinnabarinus was investigated. And the changes of several important enzymes activities in T. cinnabarinus treated with Lupeol, Stigmasterol, Ethyl palmitate were tested. The ultrastructure of T. cinnabarinus treated with Lupeol, Stigmasterol, Ethyl palmitate were observed through transmission electron microscope (TEM). The results showed that the activities of GSTase and Ca2+-ATPase in T. cinnabarinus were restrained or activated, SODase were all activated. Observation under TEM revealed that cuticle, muscular filament, nuclear membrane, mitochondria and endoplasmic reticulum were ruptured. The result suggested that Lupeol, Stigmasterol, Ethyl palmitate may be main acarocidal compound in Inula britanica against T. cinnabarinus.