Marginatin,a new germacranolide from Vernonia species

A new germacranolide, marginatin, has been isolated from three species of Vernonia from the central United States, V. marginata, V. fasciculata and V. arkansana, and its structure has been determined.     

A germacranolide and a longipinene derivative from Eupatoriadelphus purpureus

The roots of Eupatoriadelphus purpureus contain tridecapentaynene, β-pinene and five p-hydroxyaecetophenone derivatives. By contrast, the aerial parts have germacrene D, lupeol and its isomers, coumarin, a new sesquiterpene tiglate and a new germacranolide.     

A germacranolide from Inula indica

Chemical investigation of Inula indica has yielded a new germacranolide, 1β,10α-epoxy-2α,9β-dihydroxy-5β-acetoxy-6α(2-methylbutyryloxy)-germacran-8α,12-olide, whose structure and stereochemistry have been established from the spectral characteristics of the compound and its derivatives.     

Arbusculin-D from Artemisia arbuscula ssp. Arbuscula

Abstract-Arbusculin-D (I), a new eudesmanolide, has been isolated from Artemisia arbuscula Nutt. ssp. arbuscula and is present also in A. arbuscula Nutt. ssp. thermopola Beetle. It represents a structural variant in the lactone grouping.     

Ridentin-β: An eudesmanolide from Artemisia tripartita ssp. rupicola

Ridentin-B (I), a new eudesmanolide, has been isolated from Artemisia tripartite ssp. rupicola. It is biosynthetically closely allied with ridentin (IV), a germacronolide. The stereochemistry of ridentin is discussed.     

Annuithrin,a new biologically active germacranolide from Helianthus annuus

Investigations on growth inhibition in Helianthus annuus led to the isolation of a new sesquiterpene lactone, a germacranolide with an α-methylene-γ-lactone moiety. The structure of this new germacranolide, annuithrin, was elucidated by spectroscopic methods. Its biological activity has been proven by growth inhibition in straight growth tests, antibacterial tests and inhibition of DNA-/RNA-synthesis in cells of the ascitic form of Ehrlich carcinoma.     

A dimeric germacranolide and other sesquiterpene lactones from Mikania species

The investigation of two Mikania species, both previously placed in the genus Kanimia, afforded in addition to known compounds several new germ     

9α,15-Dihydroxygermacra-1(10),4-dien-11β,13-dihydro-6α,12-olide,a germacranolide isolated from Centaurea aspera subsp. stenophylla

A new germacranolide, isolated from Centaurea aspera subsp. stenophylla, was identified as 9β,15-dihydroxygermacra-1 (10)4-dien-11β,l3-dihydro-6α,12-olide by spectroscopic evidence and partial synthesis.     

Sesquiterpene lactones of Artemisia: TLC analysis and taxonomic significance

Samples of Artemisia arbuscula ssp. arbuscula, A. tridentata ssp. tridentata, ssp. wyomingensis, ssp. vaseyana and ssp. vaseyana f. spiciformis were collected from various locations in Montana and analyzed by TLC for their sesquiterpene lactone content. Artemisia tridentata ssp. tridentata and ssp. wyomingensis are distinct morphologically and chemically, whereas ssp. vaseyana has three distinct chemical groups not yet separated morphologically. Artemisia arbuscula ssp. arbuscula and A. tridentata ssp. vaseyana f. spiciformis are easily separated by morphology but have identical TLC patterns. It has been further shown that the sesquiterpene lactones produced for a particular species or subspecies are the same regardless of the time of the year collected, although the quantity varies from winter to summer.     

Rupicolin-A and -B,rupin-A and -B,and cumambrin-B oxide from Artemisia tripartita ssp. Rupicola

Five new sesquiterpene Iactones have been isolated from Artemisia tripartita Rydb. ssp. rupicola Beetle. The compounds, all guaianolides, are structurally related in what appears to be a sequence in which epoxidation plays the principal role.     

Viguilenin,a germacranolide from Viguiera linearis

The new germacranolide, viguilenin, was isolated from Viguiera linearis and its structure was established by chemical and spectroscopic means.     

Sesquiterpene alcohols from Artemisia pygmaea

Artemisia pygmaea Gray contains two sesquiterpene alcohols: the known cryptomeridiol (I) and pygmol (II), a new compound. No sesquiterpene lactones were found in the plant although other species of the section Tridentatae Rydb., with which A. pygmaea has been classified, are usually rich in lactones.