Chemical Constituents From Vernonia Amygdalina Del.and Their Antitumor Activity

Vernonia amygdalina Del.from the family Asteraceae is distributed throughout tropical Africa,especially in West Africa.It is a kind of edible plants.Many people called it bitter leaves because of its bitter taste.According to the literature,it mainly contains steroidal saponins,flavonoids,sesquiterpene lactones,sterols,fatty acids and so on.Traditional treatments include tonsillitis,fever,malaria,diabetes,pneumonia,jaundice,anemia,stomach illness and ascariasis.In the recent years,pharmacological activity studies have shown anti-inflammatory,anti-oxidation,anti-tumor,anti-malaria and other pharmacological effects.Chemical constituents from Vernonia amygdalina Del.and their cytotoxicity activity were designed to investigate in the present study.The 95%ethanol extract was suspended in H2O and partitioned in petroleum ether,dichloromethane,ethyl acetate,and n-butyl alcohol in sequence,to obtain four extracts.The conventional separation technology was used to separate and purify the extracts respectively,such as D-101 macroporous resin column chromatography,Sephadex LH-20 gel column chromatography,ODS reversed phase column chromatography,silica gel column chromatography and semi-preparative HPLC.Twenty compounds were obtained including four new compounds and sixteen known compounds.Their structures were determined by spectroscopic methods including EST-MS,1D NMR,2D NMR and DEPT spectrometry.All compounds were tested by MTT methods on the cell lines BT-549,MDA-MB-231,MCF-7,Hela and A549.From the 95%ethanol extract of Vernonia amygdalina Del.,twenty compounds were isolated and determined:vernoniamyoside A(1),vernoniamyoside B(2),vernoniamyoside C(3),vernoniamyoside D(4),vernoamyoside D(5),vernonioside B2(6),apigenin(7),luteolin(8),quercetin(9),apigenin-7-O-?-D-glucoside(10),luteolin-7-O-?-D-glucoside(11),5,7-dihydroxy-4H-4-chromenone(12),spinasterol(13),?-sitosterol-3-O-butyl(14),hydroxyvernolide(15),caffeic acid(16),3,4-dihydroxybenzoic acid(17),bis(2-ethylhexyl)phthalate(18),n-hexadecane acid(19)aurantiamideacetate(20).Compound 1-4 were new compounds and 7,9,10,12,16,17,18,20 were isolated from Vernonia amygdalina Del for the first time.The anti-tumor activity studies of compounds 1-20 have shown that:compound 1 showed significant cytotoxicity on cell line BT-549(IC50:6.28 ?M)while 2 and 6 showed certain cytotoxicity(IC50:18.36?M,11.90 ?M).Compounds 2 and 5 had certain cytotoxicity on cell line MCF-7 with IC50:12.31?M and 11.54 ?M.Furthermore,compound 15 showed significant cytotoxicity on cell line Hela with IC50 value of 2.71?M.And compounds 10 and 15 showed inhibitory activity against cell line A549.The cytotoxicity of other compounds were positively correlated with the concentration.In summary,this article aimed to isolate and purify the compounds through the traditional separation technology and determine them by modern spectrum technology from the leaves of Vernonia amygdalina Del.It is of great significant to preliminary studies of anti-tumor activity,and can further clarify the important meaning of relationship between its chemical composition and drug action.The cytotoxicity of all compounds shows Vernonia amygdalina Del.will be certain valuable and potential in the anti-tumor research.