Eucannabinolide and other constituents of Schkuhria virgata

Isolation of eucannabinolide, its 3-isovaleroyl analog and pectolinarigenin from Schkuhria virgata (La Llave et Lex.) DC. is reported. The identity of eucannabinolide, which exhibits in vivo antileukemic activity, with ‘hiyodorilactone A’, ‘20-hydroxychromolaenide’ and ‘schkuhrin I’ is discussed.     

11,13-Dehydroeriolin,schkuhrioidin and schkuhriolid,germacranolides from Schkuhria species

The isolation is reported of the new germacrolide, 11,13-dehydroeriolin, the new melampolide schkuhrioidin and schkuhriolide from Schkuhria schkuhrioides. 11,13-Dehydroeriolin is also a constituent of S. virgata. The structure and stereochemistry of the new compounds were established on chemical and spectroscopic grounds.     

Sesquiterpene lactones from Schkuhria anthemoidea var. wislizenii

We report here on the isolation and characterization of two new elemanolides and the known germacrolide 11,13-dehydroeriolin from Schkuhria anthemoidea var. wislizenii.     

A heliangolide from Schkuhria pinnata

Re-investigation of the aerial parts of Schkuhria pinnata afforded in addition to the heliangolides isolated previously a new one, the structure of     

Germacranolides from Lychnophora species

The investigation of three further Lychnophora species and the re-investigation of one species afforded, in addition to known compounds, seven new sesquiterpene lactones all being closely related to those isolated before from the subtribe Lychnophorinae. Furthermore, a new bisabolene diketone was present in one species. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation of the genus is briefly discussed.     

Germacranolides from Stilpnopappus species

The investigation of four Stilpnopappus species afforded in addition to known compounds seven new germacranolides, all related to glaucolides. The structures were elucidated by spectroscopic methods. The chemotaxonomy of the genus is discussed briefly.     

Germacranolides from Dicoma tomentosa

An investigation of the aerial parts of Dicoma tomentosa afforded four new germacranolides and four melampolides together with urospermal A and its 11β,13-dihydroderivative. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.     

Germacranolides from Piptolepis Ericoides and Vanillosmopsis species

The aerial parts of Piptolepis ericoides afforded in addition to known compounds two new germacranolides, a zexbrevanolide and piptolepolide, tentatively characterized as a germacranolide with a trans-disubstituted double bond. From the aerial parts of two Vanillosmopis species in addition to goyazensolide, a new isomer with an exocyclic double bond was isolated.     

Germacranolides in Helianthus mollis

Desacetyleupaserrin, eupaserrin and two new germacranolides, mollisorin-A and mollisorin-B, were isolated from H. mollis. ¹H NMR and ¹³C NMR data and chemical interconversions of the four germacranolides are described.     

Germacranolides from Eupatoriastrum nelsonii

The aerial parts of Eupatoriastrum nelsonii afforded, in addition to known sesquiterpene lactones, four new lactones all closely related to the germacranolides isolated previously from other genera of the tribe Eupatorieae. The structures were elucidated by spectroscopic methods. Chemotaxonomic aspects are discussed briefly.     

Three furanoheliangolides from Calea villosa

Calea villosa afforded three new sesquiterpene lactones, two furanoheliangolides and an epoxy- germacranolide, as well as several known compounds. The structures were elucidated by spectroscopic methods.     

Heliangolides from Helianthus maximiliani

The isolation is reported of tifruticin, acetyltifruticin, deoxytifruticin, acetyldeoxytifruticin, an orizabin analog and three heliangolides from Helianthus maximiliani.     

Germacranolides from Mikania grazielae

Mikania grazielae afforded two new germacranolides which were identified as 2α-acetoxyeupatolide and 2α-acetoxylaurenobiolide.     

Further sesquiterpene lactones from Calea and Viguiera species

The aerial parts of Calea clematidea gave three new germacranolides, those of Viguiera procumbens two orizabin derivatives and those of V. linearis dihydrobudlein A. In addition to these lactones, several known ones were isolated.     

Germacranolides from Viguiera microphylla

Three new germacranolides, including two heliangolides (niveusin C-2′,3′-epoxide and 1,2-dehydroniveusin C-2′,3′-epoxide) and a germacrolide (3β-hydroxy-8β-epoxyangeloyloxycostunolide-1β,10α-epoxide) were isolated from Viguiera microphylla. Their structures were established by spectroscopic analyses, including extensive ¹H NMR and ¹³C NMR decoupling experiments and chemical transformations. X-ray diffraction analysis confirmed the structure of niveusin C-2′,3′-epoxide.     

Germacranolides from Perymenium klattianum and Perymeniopsis ovalifolia

The aerial parts of Perymenium klattianum afforded, in addition to kaurane and beyerane derivatives, three germacranolides, two of them isolated for the first time. The structures were elucidated by spectroscopic methods and by some chemical transformations, which in part gave unusual products. Perymeniopsis ovalifolia gave known compounds only.     

Sesquiterpene lactones from Syncretocarpus sericeus

The aerial parts of Syncretocarpus sericeus afforded in addition to known compounds a new heliangolide. The chemistry supports the placement of thi     

New germacrolide- and heliangolide-type sesquiterpene lactones from Melampodium linearilobum

Chemical analysis of Melampodium linearilobum yielded, besides coumarin, seven germacrolide-type sesquiterpene lactones, linearilobin A to G and two heliangolides, linearilobin H and I. All new sesquiterpene lactones are oxygenated at C-14 and C-15 and differ by the number and types of ester moieties at C-8, C-14 and C-15. M. linearilobum represents the first species within the genus known to produce germacrolides and heliangolides instead of the more common melampolides.