11β,13-Dihydroguaianolides from Artemisia douglasiana and a thiophene acetylene from A. schmidtiana

The aerial parts of Artemisia douglasiana afforded, in addition to some known sesquiterpene lactones, 22 new closely related guaianolides. A new thiophene acetylene was isolated from the aerial parts of A. schmidtiana together with some known sesquiterpene lactones. The structures were elucidated by high field ¹H NMR spectroscopy.     

Poskeanolide,a seco-germacranolide and other sesquiterpene lactones from Vernonia species

The aerial parts of Vernonia cinerea, collected in Costa Rica, gave four new hirsutinolides while a sample from Malawi afforded glaucolide E and two related lactones. From V. poskeana a seco-germacranolide biogenetically closely related to a new glaucolide was isolated. The investigation of two Critoniopsis species gave in addition to known lactones a further glaucolide and a vernopatensolide. A related species, V. flexipappa, only gave glaucolide B. The structures were elucidated by highfield NMR spectroscopy.     

Five mikanolide derivatives from mikania cynanchifolia and their biogenetic relationships

The investigation of the aerial parts of Mikania cynanchifolia afforded, in addition to miscandenin, five new sesquiterpene lactones, miscandenin-1,2-epoxide, an isomiscandenin and three further dilactones related to mikanolide. The structures of these new compounds were elucidated by high field ¹H NMR spectroscopy. The biogenetic relationships of the sesquiterpene lactones are briefly discussed.     

Hirsutinolides,glaucolides and sesquiterpene lactone from Vernonia species

The investigation of nine Vernonia species afforded in addition to known sesquiterpenes 28 new ones. The structures were elucidated by high field ¹H NMR spectroscopy and the configurations were determined by NOE difference spectroscopy and, in one case, by X-ray analysis. The results indicated that configurations of several previously reported sesquiterpene lactones have had to be revised. In addition to known types two new ones, the jalcaguaianolides and the vernojalcanolides, are described. Furthermore some unusual reaction products are presented which, in part, led to some natural occurring lactones.     

Further eudesmanolides and xanthanolides from Telekia speciosa

The re-investigation of the aerial parts of Telekia speciosa afforded five new sesquiterpene lactones, two eudesmanolides and three xanthanolides, all closely related to those isolated before from this species or from related genera. The structures were elucidated by ¹H NMR spectroscopy.     

Allenic germacranolides,bourbonene derived lactones and other constituents from Vernonia species

An investigation of seven Vernonia species, mainly from northern Brazil, afforded in addition to known compounds three new unusual sesquiterpene lactones with an allenic group. Intensive NMR studies fully established the structures. Furthermore, two lactones derived from bourbonene, two new glaucolides, a new furansesquiterpene, a nerolidol derivative and two other sesquiterpenes derived from eudesmane were isolated. The biogenetic relationships of the sesquiterpene lactones present in Veronia species as well as the chemotaxonomic aspects are discussed.     

Eudesman-12,8β-olides and other terpenes from Artemisia species

The aerial parts of Artemisia iwayomogi afforded, in addition to already known terpenes, eleven new cudesmanolides whereas four new guaianolides were found in A. gmelinii. No sesquiterpene lactones were detected in the aerial parts of A. santolinifolia which afforded two new nerolidol derivatives besides several other already known compounds. From A. caerulescens var. cretacea six eudesmanolides were isolated, one of which has not been reported previously. The structures were elucidated by high field ¹H NMR spectroscopy and chemical transformations. The chemotaxonomic significance of sesquiterpene lactones within the section Abrotanum and the subgenus Seriphidium is briefly discussed.     

Sesquiterpene lactones from helogyne hutchisonii

The aerial parts of Helogyne hutchisonii afforded, in addition to known sesquiterpene lactones, two new heliangolides and two germacranolides. The structures were elucidated by high-field ¹H NMR spectroscopy.     

Two sesquiterpene and three diterpene lactones from Acanthospermum australe

The aerial parts of Acanthospermum australe afforded two new sesquiterpene lactones, an acid and a cis,cis-germacranolide, as well as three diterpene lactones of a new type, most probably formed by intermolecular nucleophilic attack of the carboxyl group of an acid epoxide derived from geranylgeraniol. The structures were proposed on the basis of spectroscopic studies.     

Sesquiterpene lactones and eudesmane derivatives from Onopordon carmanicum

The aerial parts of Onopordon carmanicum afforded in addition to onopordopicrin and two related esters the epoxide of onopordopicrin, a new elemane derivative, two eudesmanolides and two eudesmane derivatives which most likely are the precursors of the latter lactones. The structures were elucidated by highfield NMR spectroscopy.     

Further sesquiterpene lactones from the genus Dittrichia

The aerial parts of Dittrichia graveolens afforded in addition to compounds isolated previously five new sesquiterpene lactones, two benzoic acid derivatives while D. viscosa gave two further derivatives of costic acid. The structures were elucidated by high field NMR spectroscopy.     

Seven germacranolides and four eudesmanolides from Tithonia rotundifolia

The aerial parts of Tithionia rotundifolia afforded, in addition to two known sesquiterpene lactones, eleven new ones, seven germacranolides and four eudesmanolides. The structures were determined by ¹H NMR spectroscopy.     

Sesquiterpene lactones and other constituents from Matricaria chamomilla L.

An ethanolic extract of the aerial parts of Matricaria Chamomilla L. collected at Oued Tonga near El-Kala is eastern Argelia yielded two new substances named matricolone and chamolol, together with four known compounds. The structure of the new compounds were determined by chemical transformations and NMR spectroscopy with ¹H-¹H (COSY and ROESY), ¹H-¹³C (one bond and long range correlations) two dimensional experiments. The results obtained indicate the presence of sesquiterpene lactones of the eudesmanolide, germacranolide and guaianolide types. These products can be considered to be of great interest from a chemotaxonomical point of view for this wild-growing plant, because these types of lactones have not been found together in other Matricaria species.     

Three bourbonenolides and other sesquiterpene lactones from two vernonia species

A re-investigation of V. arkansana afforded several new sesquiterpene lactones, three bourbonenolides, obviously closely related to those isolated from this plant previously, a glaucolide and a methoxy derivative most probably formed by fragmentation of the corresponding bourbonenolide. From V. profuga in addition to known lactones a new guaianolide was isolated. The biogenetic relationships of the Vernonia sesquiterpene lactones are discussed briefly.     

Glaucolide-like sesquiterpene lactones from Cotula cinerea

The aerial parts of Cotula cinerea gave, in addition to widespread compounds, a characteristic diacetylenic spiroketal enolether and several sesquiterpene lactones, three of them being glaucolide-like lactones. The structures were elucidated by highfield ¹H NMR spectroscopy.     

Balansolide and other sesquiterpene lactones from Bejaranoa balansae

The aerial parts of Bejaranoa balansae afforded in addition to known sesquiterpene lactones six new ones, two highly oxygenated germacranolides and four guaianolides including balansolide with a 2,9-ether bridge. Furthermore, two geranyl nerol derivatives were present. The configuration of some 10,14-epoxyguaianolides have been revised from 10β to 10α and the stereochemistry at C-4 in 4,5-dihydrofuroheliangolides has also been corrected to 4β-methyl. The structures were elucidated by NMR spectroscopy.     

Eudesmanolides from Artemisia judaica

The aerial parts of Artemisia judaica afforded in addition to known compounds a hydroperoxide corresponding to vulgarin as well as an isomer of the latter. The configurations of these lactones have been established by NOE difference spectroscopy.     

Sesquiterpene lactones from Michelia fuscata

Two new sesquiterpene lactones, desacetyllanuginolide and michefuscalide were isolated from Michelia fuscata along with two known lactones, dehydrolanuginolide, lipiferolide and a lignan, syringaresinol. The structures of desacetyllanuginolide and michefuscalide were determined by spectral and chemical methods.     

Anticancer sesquiterpene lactones of Michelia compressa (magnoliaceae)

Investigation of the cytotoxic active components of Michelia compressa afforded two new cytotoxic sesquiterpene lactones, michelenolide and micheliolide. Parthenolide, costunolide, santamarine, reynosin and liriodenine were also isolated and exhibited cytotoxic activity. The known sesquiterpene lactones, lanuginolide and dihydroparthenolide, were isolated but were not active. Two other new inactive sesquiterpene lactones, compressanolide and dihydroreynosin, were also obtained. The structures of michelenolide and micheliolide were confirmed by partial synthesis from parthenolide and the structure of compressanolide by partial synthesis from dihydroparthenolide.     

Cytotoxic activity of sesquiterpene lactones from Inula britannica on human cancer cell lines

Five new sesquiterpene lactones (1–5) were isolated from Inula britannica collected in the wild from Serbia along with five known compounds (6–10). Sesquiterpene lactones were isolated using centrifugal partition chromatography followed by combination of flash chromatography and semi-preparative HPLC. Isolated compounds were screened for cytotoxic activity on four different human cancer cell lines and their multi-drug resistant counterparts, as well as on normal human keratinocytes. Sesquiterpene lactones showed similar cytotoxic activity toward drug sensitive and drug resistant cancer cell lines.