Flavones,sesquiterpene lactones and glycosides isolated from Centaurea aspera var. Stenophylla

From the alcoholic extract of Centaurea aspera var. stenophylla benzoic acid, p-hydroxybenzoic acid, apigenin, 6-methoxyluteolin, 11,13-dehydromelitensin, melitensin, stenophyliolide, ethyl-7-O-apigenin-glucuronate and the glucosides of sitosterol and stigmasterol were isolated and characterized. Stenophyllolide was shown to be 9,15-dihydroxygermacra-1(10),4,11-trien-12,6-olide.     

Montafrusin,a new germacrolide from Montanoa frutescens

The investigation of Montanoa frutescens afforded a new sesquiterpene lactone of the germacrolide type, montafrusin, besides the known diterpenes kaurenic acid and its 15α-isovalerate.     

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.     

Sesquiterpene lactones from Centaurea glomerata

The investigation of the aerial parts of Centaurea glomerata afforded four new sesquiterpene lactones of the germacradienolide type and the lignan lactone arctigenin. Their structures were elucidated by spectroscopic methods.     

Sesquiterpene lactones from Centaurea solstitialis

Eight sesquiterpene lactones were isolated from Centaurea solstitialis (yellow starthistle). They are solstitialin A, repin, subluteolide, acroptilin, janerin, cynaropicrin, and the new lactones solstitiolide and episolstitiolide.     

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.     

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.     

The structure and stereochemistry of artemin

Artemin was isolated from the aerial part of Artemisia maritima. Its structure and stereochemistry were determined on the basis of chemical transformations and spectral evidence     

Sesquiterpene lactone glycosides from Crepis capillaris

Four new sesquiterpene lactone glucosides, in addition to known compounds, have been isolated from the roots of Crepis capillaris and their structures elucidated on the basis of spectral analysis and hydrolytic studies.     

Six new melampolides from Tetragonotheca helianthoides

Chemical analysis of Tetragonotheca helianthoides L. yielded six new melampolide-type sesquiterpene lactones, tetrahelins A–F. All new compounds have the same medium ring skeleton and differ by the ester moieties at C-8 and C-9. Tetrahelin A and B contain the side chain 2-methyl-2,3-diacetoxybutanoate and tetrahelin E 3-hydroxy-3-methylbutanoate. Both ester side chains have previously not been found in sesquiterpene lactones.     

Stereostructures of inunal and isoalloalantolactone,two biologically active sesquiterpene lactones from Inula racemosa

Two new sesquiterpene lactones, inunal and isoalloalantolactone, have been isolated from Inula racemosa. Inunal, an aldehydolactone, displays considerable biological activity as a plant growth regulator. Structures have been assigned to these compounds on the basis of spectral data and chemical correlation with alantolactone and isotelekin.     

Angeloylcumambrin-B,an antimicrobial sesquiterpene lactone from Chrysanthemum ornatum var. Spontaneum

Angeloylcumambrin-B, a new antimicrobial guaianolide sesquiterpene lactone, was isolated from Chrysanthemum ornatum and the structure was determined by a combination of chemical and physical methods.     

11β,13-Dihydrolactucin,a sesquiterpene lactone from Launaea mucronata

The roots of Launaea mucronata afforded, in addition to lactucin, lactucin-8-O-acetate and the corresponding dihydro derivative, 11β,13-dihydrolactucin.     

Three new melampolide sesquiterpenes,polymatin A,B and C,from Polymnia maculata Cav. var. maculata

Three new melampolide type sesquiterpene lactones were isolated from Polymnia maculata Cav. var. maculata. Their structures were determined by spectroscopic and chemical means. Based on the presently available chemical data, the chemotaxonomic position of Polymnia within the subtribe is discussed.     

Seven guaianolides from Eupatorium chinense

Two allyl hydroperoxy guaianolide sesquiterpene lactones (peroxyeupahakonin-A and -B) and five new guaianolides (eupahakonin-A and -B, eupahakonenin-A and -B, and eupahakonesin) were isolated from E. chinense and characterized. The allyl hydroperoxy sesquiterpene lactones were characterized by spectral and chemical methods. They were prepared chemically by photosensitized oxygenation of eupahakonin-A.     

Goyazensolide,a schistosomicidal heliangolide from Eremanthus goyazensis

Isolation and structure determination of goyazensolide, a new heliangolide responsible for the schistosomicidal properties of Eremanthus goyazensis Sch.-Bip., is reported.