Chemical Constituents From Tephrosa Purpurea Seeds And Residue Analysis Of The Active Compounds Rotenone And12a-hydroxyrotenone

The paper reviewed the situation of botanical pesticide development. The methanol extracts from Tephrosia purpurea seeds were isolated and identified.Analytical methods for residual dynamics of active compounds including Rotenone and12a-hydroxyrotenone were established. This dissertation includes the following sections:1.The methanol extracts were isolated with column chromatography, thin layer chromatography, high performance liquid chromatography and recrystallization, and identified on the basis of MS and NMR data. Eight compounds were isolated and identified,i. e.,6a,12a-dehydro-deguelin, Tephrosin, Obovatachalcone, Obovatin, Isolonchocarpin, Pongachin, Penduletin and Raffinose. Insecticidal activities of six compounds were determined against the ergat of Odontotermes formosanus adult and the third instar larvae of Chilo suppressalis. The results showed that five compounds (i.e., Isolonchocarpin,12a-hydroxyrotenone, Obovatin, Tephrosin and Rotenone) had possess insecticidal activity against the adult of O. formosanus; Isolonchocarpin and Tephrosin possessed weak repellent activity against O. formosanusall adults, the other compounds did not any present repellent activity against this pest. The accumulative morality of O. formosanusall adults within56hours by cross-transmitting of12a-hydroxyrotenone among the pests reached to100%, while that of the other two compounds were24.3%for Obvatin and38.7%for Rotenone. Tephrosin,12a-hydroxyrotenone and Rotenone exhibited insecticidal activity against the third instar larvae of C. suppressalis, with the values of median lethal concentration (LC50) being181.4,203.8and503.2mg/10g, respectively.2. An analytical method for residual dynamics of Rotenone in Brassica chinensis L. by solid-phase extraction (SPE) and high performance liquid chromatography (HPLC-UV) detection was described. The results showed that the samples were extracted by acetonitrile. After adding sodium chloride to salt out, then cleanup with Florisil SPE cartridges using n-hexane-ethyl ether (3:7, by vol) as eluents to provide adequate recovery of Rotenone. The detection of Rotenone was then carried out by HPLC-UV using acetonitrile-water (6:4, by vol) as the mobile phase. UV detection was made at the wavelength of290nm. The method was accurate, specific and sensitive, and presented excellent linear correlation when the concentration of Rotenone ranged from0.05mg/kg to10mg/kg. The average recoveries and the relative standard deviation ranged from85.9%to86.3%at concentration range of0.5-5mg/kg. The limits of detection (LOD) of Rotenone were0.05mg/kg. When the samples were treated with the insecticide2.5%Rotenone EC at the dose of100mL/667m2recommended by manufacturer and the dosage of300mL/667m2, the original residues of Rotenone in Brassi cachinensis were6.26and18.34mg/kg, respectively, and the corresponding degradation half-life of Rotenone in Brassi cachinensis was11.2hours and11.1hours.3. An analytical method for residual dynamics of Rotenone in tobacco by LC-MS/MS was described. The tobacco samples were extracted by acetonitrile, and then cleanup with Florisil SPE cartridges after adding sodium chloride to salt out. The detection of Rotenone was carried out by LC-MS/MS and separation was performered on Agilent ZORBAX SB-C18column by using acetonitrile-water including0.1%formic acid (5:5, v/v) as the mobile phase. The method was accurate, specific and sensitive, and presented good linear correlation at the concentration range from0.005mg/kg to0.2mg/kg. The average recoveries and the relative standard deviation ranged from96.8%to97.3%. When tobacco plants were spraied with2.5%Rotenone EC at100m1/666.7m2and300m1/666.7m2, the respective original residues of Rotenone in tobacco were10.56mg/kg and20.01mg/kg, and the corresponding half-life of Rotenone in tobacco was20.4hours and24.6hours under the condition of the darkness. At the same dosage, in the sunshine the respective original residues were9.61mg/kg and19.76mg/kg, the half-life of Rotenone in fresh tobacco leaves was10.34hours and12.28hours, respectively.4. A method for Rotenone and12a-hydroxyrotenone residues in tobacco by LC-MS/MS was described. The tobacco samples were extracted by acetonitrile, the extracts was cleanup with Florisil SPE cartridges after adding sodium chloride to salt out. Rotenone and12a-hydroxyrotenone were dtcected simultaneously under ESI+model by LC-ESI-MS/MS and separation was achieved on Agilent ZORBAX SB-C18column by using acetonitrile-water including0.1%formic acid (5:5, v/v) as the mobile phase. The method was accurate, specific and sensitive, and exhibited good linear correlation at the concentration range from0.002mg/L to0.05mg/L. The average recoveries and the relative standard deviation of Rotenone and12a-hydroxyrotenone ranged from95.8%to97.9%.