Studies On The Insecticidal Constituents Of The Roots Bark Of Periploca Sepium And Tripterygium Hypoglaucum

An available pathway to develop new kinds of insecticides is to find novel lead compounds from plants. For this purpose, insecticidal components of Periploca sepium and Tripterygium hypoglaucum were studied in this paper.1. The totale of 19 compounds were isolated by means of bioassay-guided chromatography from P. sepium .The structures of these compounds were determined by 1H-NMR, 13C-NMR,X-ray crystal diffraction and mass spectral analysis as Periplocoside R, P, Q, D, F, L, K, E, A, X, A′, 2-O -acetyl-β-D-dit-(1→4)-β- D-cym -(1→4)-β- D-cym-(1→4) -β-D-cym- (1→4)- L- oleandronic acid–δ-lactone, Oligosaccharide D2, Oligosaccharide F2, Periplogenin, Isovanillin,β-amyrin acetate, Glycoside H1 and Oligosaccharide NW, Five of them were new compounds: Periplocoside R, Periplocoside P, Periplocoside Q, Periplocoside X and Oligosaccharide NW.2. Bioassay results showed that periplocoside D, F, A and X had only stomach toxic activity against the 3rd larvae of Mythimna separata. After administration 48h, the stomach medium lethal concentrations values (LC50) of these compounds were 0.39, 0.34, 4.10 and 0.11 mg·mL-1, respectively. Periplocoside R,Q, D, F, A,X, Periplogenin and Oligosaccharide NW had stomach toxicity against the 3rd instar larvae of Plutella xyllostella. After administration 48h, the LC50 of these compounds were 2.03, 1.30, 1.21, 1.39, 3.62, 0.89, 1.16 and 1.17 mg·mL-1, respectively. The toxic symptoms of M. separata showed that digestive system might be the target of periplocosides.3 The pathway of fragment forming and cleavage of compound Periplocoside E and A were investigated by ESI MSn. A MS method used to identify Periplocosides in the process of screening new compounds was developed.4. Eight insecticidal constituents of T. hypoglaucum were isolated by means of bioassay-guided chromatography. The structures of 7 compounds were determined by 1H-NMR, 13C-NMR , X-ray Crystal diffraction and mass spectral analysis as wilfortrine,wilforgine,wilfordine ,wilforine, wilfordsuine,peritassines A and wilfordinine G. wilfordinine G is first isolated from T. hypoglaucum. 5. Bioassay results showed wilfortrine and wilforgine had only stomach toxic activity against the 3rd larvae of M. separata , but wilfordine and wilforine had strong contact activity against the 4th larvae of M. separata and stomach activity against the 3rd larvae of Agrotls ypsilon. Medium narcosis dose (ND50) values of wilfordine and wilforine were 0.33μg·larvae-1 and 0.06μg·larvae-1 respectively against M. separata, and 5.66μg·larvae-1 and 1.24μg·larvae-1 respectivelly against A. ypsilon. ND50 values of wilfortrine and wilforgine were 18.10μg·larvae-1 and 7.40μg·larvae-1 respectivelly against M. separata.Peritassines A, K7 and wilfordinine G had strong contact activity against the 4th larvae of M. separata and medium leathal dose (LD50) values of them were 0.069μg·larvae-1, 0.030μg·larvae-1 and 0.060μg·larvae-1 respectivelly against M. separata. The toxic symptoms of M. separata showed that nerve or/and muscle system might be the target of these dihydroagarofuran sesquiterpene pyridine alkaloids.