Effects of the Root Extracts of Stellera Chamaejasmel L. on the Activity of Two Enzymies of Tetranychus cinnabarinus

The root of Stellera Chamaejasmel L. was extracted with three different polarity organic solvents methanol, chloroform and petroleum ether respectively, and the acaricidal activities of the root extracts against the Tetranychus cinnabarinus were tested. The results showed that the crude petroleum ether extract of the root of S. Chamaejasmel had the strongest acaricidal activity against T. cinnabarinus. The adjusted mortality of the crude petroleum ether extract was 83.87%, which was higher than the chloroform extract (48.03%) and the methanol extract (19.84%). The crude petroleum ether extract was re-extracted with the liquid-liquid extraction method. The acaricidal activity of the petroleum ether re-extracts was higher than that of methanol. The petroleum ether re-extracts of the root of S. Chamaejasmel was separated into 15 fractions with the column chromatography on silica gel. The acarocidal activities of the 15 fractions were identified respectively. The bioassay results indicated that the adjusted mortalities of group 2 (G2), group 7 (G7), group 8 (G8), group 9 (G9) and group 11 (G11) were 89.99%, 90.23%, 72.17%, 66.30% and 61.64% respectively and were higher than the other groups obviously(the adjusted mortalities were lower than 60%, F=1.599, df=49, P<0.05). The G7 group with the highest acaricidal activities was selected for the further research. The activity of ATPase and acetylcholinesterase (TChE) of T. cinnabarinus were assayed by the colorimetric method after the female spider mites were treated with the G7 extracts of the root of S. Chamaejasmel. The result showed that the activities of Na⁺K⁺-ATPase, Ca²⁺Mg²⁺ATPase and acetylcholinesterase of the treated female mites were inhibited significantly. We supposed that the nervous system of the mites T. cinnabarinus was the main target on which the petroleum ether extract of the root of S. Chamaejasmel worked.