Melampolides and germacranolides from Stevia amambayensis

From the aerial parts of Stevia amambayensis in addition to known compounds three new sesquiterpene lactones, a grazielic acid derivative and two melampolides were isolated. The roots gave two new bisabolene derivatives.     

Bisabolene derivatives from Stevia salicifolia

The aerial parts of Stevia salicifolia afforded two new bisabolene type sesquiterpenes. The structures were elucidated by spectroscopic, chemical transformations and correlation with 15-acetoxy bisabol-1-one.     

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.     

Sesquiterpene lactones from Stevia ovata and crystal structure of 11,13-dehydroeriolin

The aerial parts of Stevia ovata afforded three sesquiterpene lactones, of which one was new. Its structure was established by spectroscopic methods and chemical reactions. One of the compounds, 4α,5β-epoxy-8-epi-inunolide was chemically correlated with 11,13-dehydroeriolin. The structure of the latter was confirmed by single crystal X-ray diffraction. The conformation of 11,13-dehydroeriolin in the solid is chair-chair [¹⁵D₅,₁D¹⁴].     

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.     

Dimeric guaianolides and other constituents from Gochnatia species

The roots of Gochnatia polymorpha afforded two new bisabolene derivatives and four dimeric guaianolides, two of them being isolated previously from G. paniculata. The aerial parts gave two further dimeric guaianolides. The aerial parts of G. hypoleuca afforded three new germacran-8,12-olides, a germacranolide acid and four additional dimeric guaianolides, which may be characteristic for this genus, while the presence of oxygenated germacranolides seems to be typical for the whole subtribe.     

Sesquiterpene lactones from centaurea coronopifolia

The aerial parts of Centaurea coronopifolia afforded three new germacronolides, two of which are closely related to balsamin. The third is a new derivative of stizolicin, which is also present. The aerial parts also yielded four 6-methoxylatedflavonoids an spectroscopic methods.     

Eremophilane-, bisabolane- and shikimic acid-derivatives from Portugese Senecio species

The aerial parts ofSenecio lividus afforded four triesters of shikimic acid, four eremophilanes and two bisabolene epoxides. The roots ofS.pyrenaicus ssp.caespitosus gave a known furoeremophilane while the aerial parts afforded a new one with a rare substitution pattern.S.doronicum contained known furoeremophilanes. The structures were elucidated by various high field NMR techniques.     

Sesquiterpene lactones from Mikania species

The aerial parts of Mikania guaco afforded in addition to a known eudesmanolide three new ones. The aerial parts of M. vitifolia gave two guaianolides, both being 3-chlorodehydroleudocin derivatives and a seco-germacranolide related to pycnolide. The structures were elucidated by highfield NMR techniques. The proposed position of the hydroxyl group in a chloroguaianolide from a Lasiolaena species has to be revised.     

Diterpenes from Baccharis species

The aerial parts of Baccharis minutiflora afforded in addition to known compounds eight new ent-kaurane derivatives, one being a homo kaurane, while the aerial parts of B. alatemoides gave two pairs of epimeric clerodane derivatives, which, however, had to be modified chemically before they could be separated. The stereochemistry of these diterpenes could not be elucidated with certainty.     

Kaurenic acid derivatives from Stevia eupatoria

Two kaurene type diterpenes were isolated from the aerial part of Stevia euphoria. Their structures and stereochemistry were established by carbon and ¹H NMR, chemical transformation and correlation with known compounds.     

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.     

Ent-kauranes and trachylobanes from Helianthus radula

The aerial parts of Helianthus radula afforded a variety of known ent-kauranoic acids as well as two new substances, 11-oxotrachyloban-19-oic a     

New germacranolides from Inula heterolepis

The aerial parts of Inula heterolepis afforded two new germacranolides and a new eudesmanolide, all closely related to haageanolide, which was also isolated.     

Constituents of the genus Oxylobus

The aerial parts of Oxylobus arbutifolius and O. adscendens gave eudesmanolides and labdane derivatives as well as two new euparin derivatives.     

A mosquito larvicide in Spilanthes mauritiana

The methanol extract of fresh vegetative aerial parts of Spilanthes mauritiana afforded, after repeated chromatographic separations and mosquito larvicidal bioassays, a potent mosquito larvicide N-isobutyl-2E,4E,8^E,10Z-dodeca-2,4,8,10-tetraenamide.The structure of the compound followed from spectroscopic considerations. It gave 100% mortality against third instar larvae of Aedes aegypti at 10⁻⁵ mg/ml.     

15-oxo-zoapatlin,a diterpene lactone from Viguiera maculata

The isolation of a new diterpene lactone and two known diterpenoid acids from the aerial parts of Viguiera maculata is reported.     

Millerenolides,sesquiterpene lactones from Milleria quinqueflora

The aerial parts of Milleria quinqueflora afforded 17 new germacranolides (five melampolides and 12 millerenolides), two ent-pimarene and two ent-kaurene derivatives as well as two alicyclic diterpenes and a galactoside. The structures were elucidated by NMR spectroscopy. The chemotaxonomic situation is discussed.     

Eudesmanolide from Centaurea granata

Investigation of the aerial parts of Centaurea granata afforded, in addition to two known polymethoxylated flavones, a new eudesmanolide. The structure of the new compound was elucidated by spectroscopic methods as 8α-hydroxy-11β,13-dihydro onopordaldehyde.     

Two eudesmanolides from Sonchus macrocarpus

The aerial parts of Sonchus macrocarpus afforded, in addition to known triterpenes, two new eudesmanolides.