Study On The Chemical Constituents And Antioxidant Activity Of Cynanchum Stauntonii (Decne.) Schltr. Ex Levl.

Cynanchum stauntonii (Decne.) Schltr. ex Levl., a perennial medicinal herb of the genus Asclepiadaceae Cynanchum chinense,the family of Asclepiadaceae,is also known as zhu ye bai qian and riparian homonoia root,it has been commonly used as antitussives and expectorants in traditional Chinese medicine. The pharmacology experiments and clinical verification show that the Cynanchum stauntoni has great curative effect on acute or chronic bronchitis. Except the efficacies for relieving cough and asthma, the Cynanchum stauntoni also achieves sputum of respiratory system disease, asthma symptoms have obvious improvement, good analgesic and anti-inflammatory effect. So far the main native organic compounds isolated from Cynanchum stauntoni such as steroids, C21 steroidal saponins, alkaloids, three terpenoids, flavonoids, benzene derivatives, carbohydrate and fatty acid, phytosterols and small molecular aromatic compounds, with C21 steroidal saponins mainly.According to the experiment, eight monomer compounds are finally obtained by separating ethanol extract of dichloromethane and ethyl acetate extract at the overground parts of the Cynanchum stauntoni through positive and reverse phase silica gel column chromatography and glucan gel column chromatography.The eight compounds:Hancockinol(1),Stigmasterol(2),5-hydroxymethyl furfural(3),5,7-dihyodroxy-6,8-methyl-3-(4’-hydroxy-3’-methoxybenzyl)chroman-4-one(4),(25R)-5 a-spirostan(5),Bis(2-ethylhexyl)phthalate(6),Phthalic acid butyl isobutyl ester(7) and Ursolic acid(8) are analyzed and identified by modern spectroscopy methods such as nuclear magnetic resonance and flight mass spectrometry according to physical and chemical properties. Meanwhile, the in vitro screening of active parts of the Cynanchum stauntoni and the evaluation of the radical-scavenging activity of monomer compounds are realized by using a DPPH radical system. Firstly, in the DPPH antioxidant activity screening experiments, the DPPH is selected to carry out antioxidant activity in vitro screening on four parts, namely ethanol extract of the Cynanchum stauntoni, dichloromethane extract of the ethanol extract, ethyl acetate extract and an aqueous layer part. The results show that the four screened parts of the plant have antioxidant activity respectively, IC50 values are 0.373 mg·mL-1,0.402 mg·mL-1,0.122 mg·mL-1,0.279 mg·mL-1. In addition, the eight compounds obtained by separating are subjected todetermination of antioxidant activity in vitro. The results demonstrate that compound 2,5,7 and 8 show stronger antioxidant capacity because the IC50 values of the compound 2,5,7 and 8 are 5.15 μM,3.35 μM,1.48μM, 6.16 pM. by calculation.