Studies On The Phytotoxic Constituents Of Stellera Chamaejasme

Stellera chamaejasme L.(Thymelaeaceae)is a perennial herb.In recent years,this plant is one of the most toxic and ecologically-threatening weeds because of its strong competitive ability and phytotoxicity.In some places,S.chamaejasmeL.has been regarded as the "warning light" of grassland desertification.In order to lay a foundation for the research and development of herbicides based on S.chamaejasme,the phytotoxic constituents of this plantwere studied under the guidance of phytotoxicity tracking in vitro.In the first chapter,the chemical constituents and pharmacological activities of S.chamaejasme were reviewed,and the phytotoxicity was emphasized.In the second chapter,different extracts of S.chamaejasme(water-soluble extract,ethyl acetate extract,chloroform extract)were prepared by conventional solvent extraction method.By employing Elymus dahuricus L.as the tested plant,the phytotoxicity of different extracts was evaluated in vitro,the ethyl acetate extract and chloroform extract were identified as the active extracts.The chemical components of the active extracts were separated and identified by a variety of column chromatography techniques combined with spectroscopy,twenty-two compounds were isolated from the chloroform extract,identified as(1S,7R,10S)-3-oxoguaia-4(5),11(12)-dien-1,10-diol(1),(1R,7R,10S)-1-hydroxyl-guaia-4,11-dien-3-one(2),1?,2?,10?-trihydroxyl-guaia-4,1-dien-3-one(3),chamaejasmone E(4),chamaej aslactone A(5),stelleraguaianone A(6),1?-hydroxyl-10?H-guaia-4,1-dien-3-one(7),chamaejasmone D(8),(11S)-3-oxo-1,7,10?H-guai-4-en-12-ol(9),daphnauranol A(10),daphnauranol B(11),(11),holosericin B(12),daphnoretin(13),3-Methoxy-1,5-diphenylpentan-1-one(14),(+)-3-hydroxy-1,5-diphenyl 1-pentanone(15),R-(-)-daphneolone(16),2-hydroxydiplopterol(17),(+)-hinokinin(18),pinoresinol(19),12-O-benzoylphorbol 13-octanoate(20),pimelotides A(21),ruixinglangdusu B(22);Among the above compounds,compounds 1-12 are sesquiterpenoid,and compounds 1-4 are new compounds.Compound 5 has a novel rearrangement framework.In the third chapter of this paper,the phytotoxicity of twenty-two compounds were evaluated.The results showed that compounds 9,12,13,14,15,16 and 18 had inhibitory effects on the root growth of Elymus.Among the above compounds,Compounds 14,15 and 16 exhibited extremely strong inhibition on the root growth of Elymus with IC50 values 98.16 ?M,189.32 ?M,364.29 ?M;Compounds 9,12,13,18 showed weak inhibition.The structure-activity relationship of Compounds 14,15 and 16 shows that the methoxy group at C-3 position is the active group,the activity of S configuration at C-3 position is higher than that of R configuration,and the substitution of C-4 on benzene ring by hydroxyl group can reduce the activity of the compound.