Studies On Akaloid Constituents Of Four Medicinal Plants And Antifeedant Activities Of Spodoptera Exigua Hiibner

Natural products are of great importance in the resource of green pesticides.Pyrrolizidine alkaloids and diterpenoid alkaloids found in many medicinal plants have appeal to many researchers in recent years for their complex structures and chemical defense against pathogens and insects.The systematic phytochemical investigation on those plants will not only provide solid proof of chemical constitutes for plant taxonom,but also help on the discovery of active lead compounds.It is of great significance to development of the new botanical pesticides and to utilization the characteristic plant resources in China.This thesis includes two parts.In part one,the phytochemical investigation on four plants including Liparis nervosa(Thunb.)Lindl.,Aconitum leucostomum Vorosch.,Aconitum soongaricum var.pubescens and Delphinium delavayi Franch were elaborated,respectively.14 new compounds,together with 47 known ones,were isolated by a combination of column chromatographies over silica gel,ODS-18 silica gel,D101 macroporous resin,aluminum oxide and Semi-preparative HPLC.Their structures were elucidated by extensive spectroscopic methods(1D,2D-NMR and HR-ESI-MS)and comparison with data reported in the literature.In part two,57 diterpenoid alkaloids isolated from Aconitum and Delphinium species were investigated for their antifeedant effects against Spodoptera exigua Hiibner.Alkaloid compositions of four palntsLiparis nervosa(Thunb.)Lindl,belonging to the family of Orchidaceae,is a herbaceous plant.From the n-butanol extract of the whole plant of L nervosa,nine new compounds nervosine ?,nervosine ?,nervosine ?,nervosine ??,nervosine XIV,nervosine ??,nervosine ??,nervosine ?? and nervosine ?? were isolated,along with one known flavone glycoside,6-C-?-L-arabinopyranosyl-8-C-?-L-arabinopyranosylapigenin.In order to evaluate the biological activitiy of these compounds,nervosine ?,nervosine?? and nervosine XV were tested for their antifeedant activities against Spodoptera exigua Hiibner,but none of these compounds showed significant inhibitory activity.Aconitum leucostomum Vorosch.(Ranunculaceae)is a perennial herb distributed in the Gansu Province and Xinjiang Uygur Autonomous Region of China.Here,the chemical components of the whole herb of A.leucostomum have been investigated,which led to the isolation and structural determination of two new atisine-type C20 diterpenoid alkaloids,leucostomine A and leucostomine B,and one new C18 diterpenoid alkaloid,leucostomine C.In addition,four lycoctonine-type diterpenoid alkaloids avadharidine,acosanine,delphatine and lycoctonine;four lappaconine-type diterpenoid alkaloids lapaconine,lappaconidine,N-deacetylappaconitine,N-acetylsepaconitine;three ranaconine-type diterpenoid alkaloids leucostine,acosepticine and finaconitine;one denudatine-type diterpenoid alkaloid denudatine and two isoquinoline alkaloids O-methylarmepavine and N-demethylcolletine were obtained from this plant.Seven known compounds,avadharidine,acosepticine,acosanin,denudatine,inaconitin,O-methylarmepavine and N-demethylcolletine were isolated from this plant for the first time.Aconitum soongaricum var.pubescens(Ranunculaceae)is a perennial herb distributed mainly in the eastern part of Xinjiang of China,Kashmir and other places.The phytochemical investigation on the whole plant,which collected from Houxia of Xinjiang,led to the isolation of one new denudatine-type C20 diterpenoid alkaloid pubesine and one new aconitine-type C19 diterpenoid alkaloid pubescensine,together with sixteen known ones including four veatchine-type diterpenoid alkaloids,songorine,songoramine,15-acetylsongorine and 12-epinapelline,together with twelve aconitine-type diterpenoid alkaloids,3-deoxyaconitine,spicatine A,altaconitine,aconitine,mesaconitine,bullatine B,15-a-hydroxyneoline,taunine,senbusine A,8-acetylneoline,14-O-acetylsenbusine A and 14-benzoylaconine-8-palmitate.The new compound pubesine is a rare denudatine-type C20-diterpenoid alkaloid bearing a 16,17-epoxy group.The study on the chemical constitunes of the roots of Delphinium delavayi Franch.,led to the isolation of fifteen known lycoctonines C19-type diterpenoid alkaloids,delphatine,deltatsine,delbonine,delbotine,lycoctonine,delsoline,delsemine A,delavaine A,delavaine B,gyalanine A,gyalanine B,anthranoyllycoctonine,delavaine A free acid,delavaine B free acid and methyllycaconitine,together with one known isoquinoline alkaloid,(+)-glaucine.Antifeedant activity of diterpenoid alkaloids against Spodoptera exigua Hiibner.Fifty seven diterpenoid alkaloids,including fourteen C18 diterpene alkaloids,thirty-nine C19 diterpene alkaloids,toegether with three napelline C20 and one denudatine C20-type diterpenoid alkaloids,were tested for the insect antifeedant activity against Spodoptera exigua Hiibner.Most of these compounds showed potential antifeedant activities,which was consistent with the result of the plant protective role of diterpenoid alkaloids.Among which,aconitine,pubescensine,3-deoxyaconitine and chasmanthinine showed considerable potent antifeedant activity(EC50?0.07 mg cm-2),followed by leucanthumsine A and chasmaconitine(EC50 ? 0.2 mg cm-2).