Guaianolides from Saussurea affinis

Cynaropicrin, 11βH-11,13-dihydrodesacylcynaropicrin, aguerins A and B, isoamberboin and the new guaianolides saussureolide and 11βH-11,13-dihydrodesacylcynaropicrin 8-β-d-glucoside were isolated from Saussurea affinis.     

Guaianolides from the leaves of Centaurea incana

Six guaianolides have been isolated from the aerial parts of Centaurea incana from Algeria. They were identified as desoxyrepin, repin or subluteolide, repin monochlorhydrin, acroptilin, janerin and repdiolide triol.     

Dimeric guaianolides from Artemisia sieversiana

The aerial parts of Artemisia sieversiana afforded in addition to known compounds five new guaianolides and four dimeric guaianolides, three of them closely related to absinthin and one derived from estafiatin as a monomer. The structures were elucidated by extensive NMR studies, which allowed the assignment of the 14 chiral centres. Artemisia frigida afforded several known compounds and one new guaianolide, 8-desoxy-cumambrin B, the most likely precursor of many guaianolides.     

Guaianolides from Centaurea kotschyi

The aerial parts of Centaurea kotschyi (var. kotschyi) afforded, besides three known sesquiterpene lactones, a new derivative of linichlorin B.     

Guaianolides and heliangolides from Hymenopappus newberryi

The aerial parts of Hymenopappus newberryi afforded two heliangolides, two thymol derivatives, as well as two new guaianolides and a trans, trans-germacranolide closely related to hiyodorilactone A. Furthermore, the ent-kaurene derivative abbeokutone was present. These results are of chemotaxonomic interest.     

Guaianolides from Tricholepis glaberrima

Cynaropicrin and 11,13-dihydrodesacylcynaropicrin were isolated from Tricholepis glaberrima.     

Guaianolides from Liatris squarrosa

The isolation of three new guaianolides related to spicatin from Liatris squarrosa is reported.     

Guaianolides from Taeckholmia species

The investigation of four Taeckholmia species afforded in addition to known desacylcynaropicrin, two new guaianolides. The structures were elucidated by spectroscopic methods and chemical transformations. The chemotaxonomy is discussed briefly.     

Guaianolides from elephantopus carolinianus

The roots of Elephantopus carolinianus afforded two guaianolides as well as two known elephantopin derivatives which were the main constituents of the aerial parts.     

Guaianolides from Ainsliaea fragrans

Five sesquiterpene lactones were isolated from Ainsliaea fragrans, two of them being new.     

Guaianolides from Acroptilon repens

Two new guaianolides have been isolated from the aerial parts of Acroptilon repens.     

Guaianolides from Calea subcordata

Chemical analysis of Calea subcordata yielded three new guaianolides, 8-epi-isobutyrylrupicolin A, 8-epi-isobutyrylrupicolin B and subcordatolide A, which represent the first guaianolide-type sesquiterpene lactones reported in the genus Calea. The structures of the new compounds were established by chemical and spectroscopic methods.     

Guaianolides and furanosesquiterpenes from Ursinia nana

The investigation of Ursinia nana afforded in addition to the typical known furanosesquiterpenes two new compounds, probably both derived from the     

Guaianolides from Centaurea canariensis

The aerial parts of Centaurea canariensis afforded four new guaianolides, all closely related to dehydrocostus lactone, and a derivative of costic acid. The structures were elucidated by spectroscopic methods.     

Guaianolides,heliangolides, diterpenes and cycloartenol derivatives from Balsamorhiza sagittata

Investigation of the aerial parts of Balsamorhiza sagittata afforded 12 new sesquiterpene lactones, five guaianolides, three heliangolides, three germacranolides and two geranylnerol derivatives. From the roots eight cycloartane derivatives, a hydroxylanosterone and hexacos-1-ene were isolated. Structures were elucidated mainly by spectroscopic methods, especially high field NMR. The chemotaxonomic situation is discussed briefly.     

Sesquiterpene lactones from Sonchus macrocarpus

Eight sesquiterpene lactones were isolated from the roots of Sonchus macrocarpus. The eudesmanolides 15-hydroxy-4β, 15-dihydroreynosin and 15-hydroxy-4β, 15, 11β, 13-tetrahydroreynosin were isolated for the first time.     

Guaianolides from Cynara sibthorpiana

The aqueous extract of the leaves of Cynara sibthorpiana afforded a terpenoid alcohol vomifoliol (= blumenol A) and three guaianolide sesquiterpene lactones, namely the cytotoxic zaluzanin-C, solstitalin and a new guaianolide named as sibthorpine.     

Guaianolides from Gochnatia smithii

The structure and stereochemistry of 8α-acetoxy and 8α-tigloyloxy dehydrocostus lactones, two guaianolides isolated from the aerial parts of Gochnatia smithii, were established by chemical and spectroscopic methods.     

Pseudoguaianolides related to confertin from Stevia isomeca

The aerial parts of Stevia isomeca afforded, in addition to known compounds, four new sesquiterpene lactones, three pseudoguaianolides related to stevin and a xanthanolide. The structures were elucidated by spectroscopic methods and a few chemical transformations.