A Study On Chemical Composition And Bioactivity Of Root Bark From Periploca Sepium

Periploca sepeium Bge belongs to Asclepiadaceae family and distributes widely in China. In shaanxi province, the plant chiefly growths in Qin-Ba mountain, Guanshan mountain, Huanglong mountain and Qiaoshan mountain and has plenty of resource. In order to exploit and use the plant resource, we studied the chemical composition and farm function on the root bark of Periploca sepium .A preliminary study on chemical composition of root bark from Periploca sepium was accomplished. It is indicated that the root bark contains amino acids, carbohydrate and its glycosides, organic acids, saponins, alkaloid, phenols, cardiac glycosides, lactones, coumarins and its glycosides, sterols, triterpenes, volatile oil, fats. Alkaloid of them is first determined in the plant. Meanwhile, Extracts of petroleum, ethyl acetate, n-butyl alcohol and water from methanol crude extracts of the root bark were used to test the insecticidal activity against Schizaphis graminum(Rond.) and Mythimna separata(Walker). The results showed that n-butyl alcohol extracts possess obvious contact poison against Schizaphis graminum (Rond.) and certain stomach poison against Mythimna separata (Walker).The chemical composition of the volatile oil from Periploca sepium root bark was analyzed by means of gas chromatography-mass spectrometer (GC/MS) technique. 10 compounds of 15 components separated from the volatile oil, which constitute 94.91% the total oil, were identified. they are 4-methoxysalicylaldehyde, butyl acetate, 2-methyl-1,3-dioxy-cyclopentyl-ethyl acetate, S-[8-(diethylphosphono)octyl] ethanethioate, 1,1,3,3,-tetrabutoxy-2-propanone, 4-methyl-2-pentanone, butyl formate,1-(1-ethoxyethoxy)-butane, 2-butoxytetrahydropyran, butyl ether. Meanwhile, the result of test on insecticidal activity of the volatile oil accomplished showed that the oil possesses obvious contact poison against Schizaphis graminum.Four extracts of petroleum ether, ethyl acetate, n-butanol and water were obtained from the methanol extract of the root bark in Periploca sepeium. Compound I and compounds II, III, IV were isolated respectively from ether acetate extract and n-butanol extract by column chromatography of silica gel, C₁₈ and Sephadex-LH-20. The four compounds were identified as p-amyrin acetate, 4-methoxysalicylaldehyde lactoside, periplocoside E and a cardiac glycoside with chemical method and spectral analysis (IR,¹H-NMR,¹³C-NMR,EI-MS). Meanwhile, compounds II, III, IV were used to test on bioactivity. The results showed that II restrain wheat and rape from growth, III and IV possess contact poison against Schizaphis graminum (Rond.) and stomach poison against Mythimna separata (Walker).