Further sesquiterpene lactones from Anthemis carpatica

A new germacranolide, (E)-1alpha, 10beta-epoxy-3beta-acetoxy-6alpha-hydroxygermacra-4,11 (13)-dien-12,8alpha-olide, together with nine new highly oxygenated guaiadien-12,6alpha-olides of anthemolide, and cumambrin type were identified in the repeated examination of the aerial parts of the flowering Anthemis carpatica. In addition, six known guaianolides belonging to the same groups, also isolated previously from A. carpatica, along with two guaianolides, 2beta-hydroxyepiligustrin and cumambrin B, not found before in this species, were isolated this time.     

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.     

Two guaiane-type sesquiterpene lactones and their related sesquiterpene lactones from Porella japonica

Two new guaiane-type sesquiterpene dilactones, porelladiolide and 3α,4α-epoxyporelladiolide and a new germacranolide, 3β-hydroxycostunolide, together with the previously known germacranolides, guaianolides, pinguisane-type sesquiterpenes, and a sacculatane-type diterpene dialdehyde have been isolated from the liverwort, Porella japonica and their structures have been established by the spectral evidence and some chemical transformations. Porelladiolide, 3α,4α-epoxyporelladiolide and the sesquiterpene with α-methylene γ-lactone group showed inhibitory activity toward the germination and growth of roots of rice in the husk.     

Insect allelochemic effects of sesquiterpene lactones from Melampodium

The crude syrups of Melampodium americanum L. and Melampodium leucanthum Torr. and Gray and their principal sesquiterpene lactones, melampodin A and melampodinin A, significantly inhibit growth and deter feeding of the fall armyworm, Spodoptera frugiperda (J. E. Smith). Melampodin A and melampodinin A caused 2.3 × and 5.5 × greater S. frugiperda larval mortality, respectively, than glaucolide A, a sesquiterpene lactone with previously demonstrated insect allelochemic effects.     

Structure and absolute stereochemistry of tomenphantopin-A and -B two cytotoxic sesquiterpene lactones from elephantopus tomentosus

The structure and absolute stereochemistry of the new cytotoxic sesquiterpene lactones, tomenphantopin-A and -B, isolated from Elephantopus tomentosus, were determined from spectral data, chemical transformation and single-crystal X-ray analysis. Tomenphantopin-A and -B are two elephantopin-type germacranolides which possess an α-orientation of the oxygen substituent at C-2.     

Trypanocidal and cytotoxic effects of 30 Ethiopian medicinal plants

Trypanocidal and cytotoxic effects of traditionally used medicinal plants of Ethiopia were evaluated. A total of 60 crude plant extracts were prepared from 30 plant species using CH2Cl2 and MeOH. Effect upon cell proliferation by the extracts, for both bloodstream forms of Trypanosoma brucei brucei and human leukaemia HL-60 cells, was assessed using resazurin as vital stain. Of all CH2Cl2 and MeOH extracts evaluated against the trypanosomes, the CH2Cl2 extracts from five plants showed trypanocidal activity with an IC50 value below 20 microg/mL: Dovyalis abyssinica (Flacourtiaceae), IC50 = 1.4 microg/mL; Albizia schimperiana (Fabaceae), IC50 = 7.2 microg/mL; Ocimum urticifolium (Lamiaceae), IC50 = 14.0 microg/mL; Acokanthera schimperi (Apocynaceae), IC50 = 16.6 microg/mL; and Chenopodium ambrosioides (Chenopodiaceae), IC50 = 17.1 microg/mL. A pronounced and selective killing of trypanosomes with minimal toxic effect on human cells was exhibited by Dovyalis abyssinica (CH2Cl2 extract, SI = 125.0; MeOH extract, SI = 57.7) followed by Albizia schimperiana (CH2Cl2 extract, SI = 31.3) and Ocimum urticifolium (MeOH extract, SI = 16.0). In conclusion, the screening of 30 Ethiopian medicinal plants identified three species with good antitrypanosomal activities and low toxicity towards human cells. Dovyalis abyssinica might be a promising candidate for phytotherapy of trypanosomiasis.     

New sesquiterpene lactones from Liriodendron tulipifera

Four new sesquiterpene lactones were obtained from L. tulipifera; two germacranolides, lipiferolide (4) and epitulipinolide diepoxide (5) from the leaves, an elemanolide, epitulipdienolide (7), and an eudesmanolide, γ-liriodenolide (6) from the root bark. Structural determination was by physical and chemical methods and by direct correlation to the known epitulipinolide (3). Lipiferolide and epitulipinolide diepoxide possess cytotoxic activity against KB cells.     

Two sesquiterpene lactones from Abutilon indicum

Abutilon indicum afforded two sesquiterpene lactones identified as alantolactone and isoalantolactone. This is the first report of the occurrence of these compounds in the genus Abutilon and in the family Malvaceae.     

New sesquiterpene lactones from Inula species

An investigation of Inula helenium, I. royleana, I. salicina and I. bifrons afforded in addition to known sesquiterpene lactones 20 new lactones, the eudesmanolides 3, 6 and 8–12, the germacranolides 14–18 and 20–22, the guaianolides 23 and 25, the pseudoguaianolide 26, the xanthanolides 28 and 32 and the cyclopropane analogue 30. Structures and configurations of these new compounds were established by extensive PMR studies and by some chemical transformations. Some of the investigated species contain besides the widely distributed pentaynene 33 several known thymol derivatives together with a new one (40).     

Further sesquiterpene lactones from Helianthus maximiliani

By using HPLC, a new melampolide, a known heliangolide and three known germacrolides were isolated as minor constituents from a north central Texas population of Helianthus maximiliani. In an earlier report, we identified the germacrolide desacetyleupaserrin as the principal sesquiterpene lactone from this population.     

Koanolides B-D,new sesquiterpene lactones from Koanophyllon gibbosum

Three new germacrane-type sesquiterpene lactones, koanolides B–D (1-3) have been isolated from the aerial parts of Koanophyllon gibbosum (Asteraceae), along with the previously reported sesquiterpene lactone koanolide A and the flavonoid eupatorin. The structures of the new compounds were elucidated using spectroscopic and spectrometric data analyses, including 1D and 2D NMR, and by comparison with known spectral data. The antiproliferative activities of the new compounds were evaluated in a panel of six representative human solid tumor cell lines and showed GI₅₀ values ranging from 1.3 to 16 μM for the new molecules.     

Hirsutinolides and other sesquiterpene lactones from Vernonia species

The investigation of Vernonia compactiflora afforded in addition to known compounds a hirsutinolide and a glaucolide; the latter is most probably the direct precursor of the former. The aerial parts of V. monocephala contain the same hirsutinolide as well as the corresponding acetate, while those of V. chalybaea afforded glaucolide B. A reinvestigation of the aerial parts of V. cotoneaster gave in addition to the allenic lactone isolated before two further known ones as well as a new glaucolide. The structures of the lactones were elucidated by spectroscopic methods and some chemical transformations. The erroneously assigned stereochemistry at C-10 in the hirsutinolides has been revised. The biogenetic relationship of the Vernonia lactones is discussed briefly.     

Further sesquiterpene lactones from costa rican eupatorieae

The aerial parts of Ayapana elata afforded two new germacranolides. The configuration at C-3 in one of them was the same as that of some bejaranolides, the structures of which therefore have to be revised. Critonia quadrangularis gave in addition to known compounds three elemanolides, a germacranolide, an isodaucane derivative and tremetone derivative. Critonia hebebotrya contained large quantities of known diterpene acids. Koanophyllon pittieri gave two epimeric ent-labdanes. The structures were elucidated by highfield NMR spectroscopy.     

Eremophilane-type sesquiterpene lactones from Ligularia hodgsonii Hook

A dimeric eremophilane sesquiterpene lactone with a cyclobutane ring, biliguhodgsonolide (1) and an uncommon seco-sesquiterpene derivative, (4S,5S,6R,10R)-8,9-seco-12-hydroxyeremophil-7(11)-en-14,6;12,8-diolid-9-al (2), were isolated from the roots and rhizomes of Ligularia hodgsonii Hook. Their structures, including the absolute stereochemistry, were elucidated by spectroscopic data and CD analysis. The cyclobutane ring was confirmed by single-crystal X-ray diffraction.     

Balansolide and other sesquiterpene lactones from Bejaranoa balansae

The aerial parts of Bejaranoa balansae afforded in addition to known sesquiterpene lactones six new ones, two highly oxygenated germacranolides and four guaianolides including balansolide with a 2,9-ether bridge. Furthermore, two geranyl nerol derivatives were present. The configuration of some 10,14-epoxyguaianolides have been revised from 10β to 10α and the stereochemistry at C-4 in 4,5-dihydrofuroheliangolides has also been corrected to 4β-methyl. The structures were elucidated by NMR spectroscopy.     

Antiproliferative and apoptotic sesquiterpene lactones from Carpesium faberi

Four new (1-4) and 13 known (5-17) sesquiterpene lactones along with two known diterpenes (18, 19) were isolated from the whole plant of Carpesium faberi. The new structures were elucidated by means of spectroscopic techniques and some chemical transformations to be pseudoguaian-1α(H)-8α,12-olide-4β-O-β-d-glucopyranoside (1), 4β,10α-dihydroxy-5α(H)-1,11(13)-guaidien-8α,12-olide (2), 4β,10β-dihydroxy-5α(H)-1, 11(13)-guaidien-8β,12-olide (3), and (4S)-acetyloxyl-11(13)-carabren-8β,12-olide (4). All isolates were tested against MCF-7 human breast cancer cells using the MTT assay. Among them, the sesquiterpene lactones (except tomentosin 17) possessing an α-methylene-γ-lactone moiety were found to have in vitro antiproliferative activities, with IC₅₀ values of 3.0-38.8 μg/mL. The effects of four selected sesquiterpene lactones (guaianolide 2, carabranolide 4, pseudoguaianolide 9, eudesmanolide 13) on the cell cycle were examined using flow cytometry (FCM).     

Poskeanolide,a seco-germacranolide and other sesquiterpene lactones from Vernonia species

The aerial parts of Vernonia cinerea, collected in Costa Rica, gave four new hirsutinolides while a sample from Malawi afforded glaucolide E and two related lactones. From V. poskeana a seco-germacranolide biogenetically closely related to a new glaucolide was isolated. The investigation of two Critoniopsis species gave in addition to known lactones a further glaucolide and a vernopatensolide. A related species, V. flexipappa, only gave glaucolide B. The structures were elucidated by highfield NMR spectroscopy.