Insecticidal Activities Of Dihydrogarofuran Compounds And Their Effects On Na~+-K~+-ATPase And Carboxylesterase Of Mythimna Separata

The main insecticidal components of celastraceae plant is polyhydroxy alcohol ester and alkaloid, the basic structure of which are dihydroagarofuran. To further veritify the insecticidal activity of Dihydroagarofuran compounds, the toxicity action against Mythimna separata and Aedes albopictus were investigated under the laboratory conditions, and their effects on activities of Na~+-K~+-ATPase and CarE were also determinated. The main resultus are given as follows:1. Wilfordine and Wilforine have contact toxicity. The results showed that the ND50 of Wilfordine and Wilforine were 8.82μg/larva and 4.58μg/larvae respectively against the 3 rd instar larvae of M.separata. The LC50 values were 268.16 mg/L and 170.72 mg/L against the 3 rd instar larvae of Aedes albopictus.2. Celangulin and Dihydroagarofuran ether analogues have stomach toxicity. The results showed that the LC50 of CelangulinⅤand d were 662.33 mg/L and 340.01 mg/L against the 3rd instar larvae of M.separata; and the LC50 values were 56.14 mg/L and 98.62 mg/L against the 3rd instar larvae of Aedes albopictus. respectively. The Dihydroagarofuran ester analogues and Compounds S1～S10 have no insecticidal activity.3. The activity of Na~+-K~+-ATPase was investigated. The results showed: in vitro, the inhibition rates of CelangulinⅣand d were 38.95% and 42.12% at the concentration of 200mg/L on Na~+-K~+-ATPase from brain of 5th instar larvae of M.separata; in vivo, the inhibition rates were 42.47% and 38.67% respectively. In addition, the inhibition rates of Wilfordine and Wilforine were 43.98% and 40.68% on Na ~+ -K ~+ -ATPase. The Dihydroagarofuran ester analogues and Compounds S1～S10 have no influence on Na~+-K~+-ATPase.4. The activity of CarE from 5th instar larvae of M.separata was investigated. The results showed the CarE was activated by Wilfordine and Wilforine, the activities of CarE were increased 27.56 % and 35.83 % . Reverse, Celangulin and other Dihydroagarofuran compounds have inhibition effects on CarE, the inhibition rates of CelangulinⅣand d were 48.14% and 62.34%. In addition, Compounds b,e,and f also have notable inhibition effects on CarE. The Dihydroagarofuran ester analogues and Compounds S1～S10 have no influence on CarE.5. Based on above results, the insecticidal activity of Celangulin and Dihydroagarofuran ether analogues were related with the activities of Na~+-K~+-ATPase and CarE. The stronger inhibition effect on the two enzymes, the better insecticidal activity of the compounds. Compounds S1～S10 have no influence on the two enzymes ,and lost the insecticidal activity.