Effects Of Alkaloids From Tripterygium Wilfordii Hook.F. On Calcium Pump Of Sarcoplasmic Reticulum In Insects

Mechanism of insecticides not only play a significant roal in the study of pesticide toxicology, but also provide important theoretical basis for the development and application of new pesticides. Total alkaloids from Tripterygium wilfordii Hook.f. has shown strong anesthetic effect on Mythimna separata(Walker) larvae and many other insects. The basis can be provide for the reveal of mechanism of alkaloids from T. wilfordii by the research and study on calcium pump activity. The activity of calcium pump in Mythimna separata(Walker) larvae, M. separate adult and adult of Apis mellifera L. tested are determined in vitro and vivo. The main conclusions are given as follows:(1) The total alkaloids from T. wilfordii has strong anesthetic and stomach poison effect against the M. separate larvae, M. separate adult and adult of A. mellifera. The NC50 value is 390.0228 mg/L(48 h) against sixth instar larvae of M. separata. The LC50 values are 90.2285 mg/L(24 h) and 89.0376 mg/L(24 h) against adult of M. separate and A. mellifera with feeding treatment, respectively.(2) Typical poisoning symptoms of alkaloids from T. wilfordii against insects demonstrated as follows: feeding, mild excitation, and then gradually diminish capacity to act, anesthesia, recovery, re-feeding, and then anesthesia, recover again, action becomes worse and gradually lengthen the time for recovery, body become more and more flexible and ultimately anesthesia to death.(3) The optimal reaction conditions of calcium pump in sarcoplasmic reticulum of insects are established which are given as below:M. separate larvae: pH value was 7.5, the temperature was 36℃, ATP concentration was 1.0 mM, calcium concentration was 0.5 mM, the amount of protein in enzyme solution was 20μg, reaction time was 5 min.M. separate adult: pH value was 7.5, the temperature was 36℃, ATP concentration was 1.0 mM, calcium concentration was 0.5 mM, the amount of protein in enzyme solution was 20μg, reaction time was 5 min.A. mellifera adult: pH value was 7.4, the temperature was 37℃, ATP concentration was 0.8 mM, calcium concentration was 1.0 mM, the amount of protein in enzyme solution was 15μg, reaction time was 5 min.(4) The alkaloids from T. wilfordii has a central effect on sarcoplasmic reticulum calcium pump against three kinds of insects both in vivo and in vitro conditions. In vivo conditions, the calcium pump in M. separate larvae is activated, the deeper the symptom, the more the activation capability. Calcium pump of M. separate adults is activated over time, inhibited with the deepening of the symptoms, first activated, then inhibited with the increase of concentration. Calcium pump of adult of A. mellifera is first activated, then inhibited with the increase of concentration. In vitro conditions, calcium pump of the tested insects is first activated, then activated a weakening phenomenon with the increase of concentration.(5) Poisoning symptoms and effect on calcium pump of alkaloids from T. wilfordii against three kinds of insects have a same trend. Therefore, the calcium pump may be one of the main insecticidal target of alkaloids from T. wilfordii.