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Three new xanthanolides, 1-3, along with nine known compounds, were isolated from the aerial parts of Carpesium longifolium. The structures of the new compounds were elucidated as 1beta,4beta-epoxy-5beta-hydroxy-10alphaH-xantha-11(13)-en-12,8beta-olide (1), 1beta,4beta,4alpha,5beta-diepoxy-10alphaH,11alphaH-xantha-12,8beta-olide (2), and 4-acetoxy-1beta,5beta-epoxy-10alphaH-xantha-11(13)-en-12,8beta-olide (3) by spectroscopic methods including IR, EIMS, HRESIMS, and 1D and 2D NMR experiments. Parthenolide and michelenolide exhibited significant cytotoxic activity against cultured SMMC-7721 (human hepatoma) and HO-8910 (human ovarian carcinoma) cells.

Seven sesquiterpene lactones, (-) sivasinolide (1), a new naturally occurring eudesmanolide (altissin, 2), desacetyl-beta-cyclopyrethrosin (3), tatridin-A (4), 1-epi-tatridin B (5), 1alpha,10beta-epoxy-6-hydroxy-1,10H-inunolide (6), and spiciformin (7), were isolated from Anthemis altissima. Also isolated were 10 known flavonoids, namely, apigenin (8), kaempferol 4'-methyl ether (9), quercetin (10), quercetin 3-methyl ether (11), isorhamnetin (12), rhamnetin (13), 6-hydroxyquercetin 3,6,4'-trimethyl ether (14), isoquercetrin (15), taxifolin (16), and eriodictyol (17), and one phenolic acid, chlorogenic acid (18). The structure and the stereochemistry of compound 2 were deduced by spectroscopic methods. The in vitro activity of the sesquiterpene lactones (1-5) against Helicobacter pylori, as well as against three Gram-positive and three Gram-negative bacteria growing aerobically, was tested using the microdilution method. Compounds 8-18 have also been tested against H. pylori.

The aerial parts of Inula verbascifolia afforded two new xanthanes and a new germacranolide derivative, together with the known compounds inusoniolide, 4-O-dihydroinusoniolide and 9β-hydroxyparthenolide. The structures were determined by spectral methods (IR, HRMS,1H NMR, 13C NMR, DEPT, 1H–1H COSY, HMQC and HMBC).

Sesquiterpene lactones (SLs) are natural products responsible for the anti-inflammatory activity of a variety of medicinal plants, mainly from the Asteraceae family. Here, we investigated whether they also influence the process of exocytosis of pro-inflammatory enzymes, such as the human neutrophil elastase (HNE). Altogether, eight structurally different SLs from the eudesmanolide, guaianolide, pseudoguaianolide, and germacranolide type were studied. Neutrophils were isolated from fresh human blood. After pre-incubation with different concentrations of the respective SL and cytochalasin B, the exocytosis of elastase was initiated either by platelet activating factor or N-formyl-methionyl-leucyl-phenylalanine. Inhibition of HNE release was measured by p-nitroaniline formation. The SLs exhibited an inhibitory effect on elastase release from neutrophils challenged either by platelet activating factor or N-formyl-methionyl-leucyl-phenylalanine. Concentration-response curves were recorded and the IC(50) values ranged from 2 to 30 microM. Studies on isolated HNE showed that a selective direct inhibition on HNE can be excluded. Interestingly, the inhibitory activity did not correlate with the number of alpha,beta-unsaturated carbonyl functions. The structure-activity relationship and the molecular mechanism are discussed.

The methanolic extract of the roots of Saussurea lappa C larke , a Chinese medicinal herb Saussureae Radix, was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Among the constituents from the methanolic extract, two sesquiterpene lactones (costunolide and dehydrocostus lactone) and two amino acid-sesquiterpene conjugates (saussureamines A and B) potently inhibited LPS-induced NO production (IC 50 =1.2–2.8 μM). Saussureamines A and B in addition to costunolide and dehydrocostus lactone did not inhibit iNOS enzyme activity, but they inhibited both induction of inducible NO synthase and activation of nuclear factor-κB in accordance with induction of heat shock protein 72.

Some ester derivatives of salonitenolide have been prepared from cnicin, a germacranolide sesquiterpenoid. The compounds were tested for their antibacterial activity. The 8,15-diesters showed a good activity, comparable with that of cnicin. The 15-monoester compounds were not very active showing that esterification at the C-8 position is an important structural feature for antibacterial properties.

From aerial parts of Lactuca aculeata one new and ten known sesquiterpene lactone aglycones and glycosides were isolated, including four lactucin-type guaianolides, six costus lactone-type guaianolides and one melampolide-type germacranolide. The structure of the new compound was determined as 11β-hydroxycrepidiaside B by high resolution mass spectrometry and 1D- and 2D-NMR spectroscopy.

The structure of a sesquiterpene lactone germacranolide was defined as 1β,6β-dihydroxygermacr-4(5),10(14)-dien-8,12-olide and was the C6-epimer of (11R)-11,13-dihydrotatridin-B.

The aerial parts of Inula verbascifolia subsp. methanea yielded three new epoxygermacranolides, compounds 1-3, in addition to the previously known 9beta-hydroxyparthenolide. The structures of 1-3 have been elucidated on the basis of their spectral data (MS, CD, 1D and 2D NMR) and by quantum mechanical calculations. The in vitro cytotoxic activity of compounds 1-3 was evaluated against six human solid tumor cell lines.

The CH(2)Cl(2) extract of the aerial parts of Artemisia myriantha afforded three germacranolides derived from 13-acetoxy-3beta-hydroxy-germacra-1(10)E,4E,7(11)-trien-12,6alpha-olide, whose structures were elucidated by 2D-NMR spectroscopic analyses. Some conclusions are drawn about the possible conformations of the ten-membered germacranolide ring system from the exchange peaks seen in the NOESY spectra, and an estimate is made of the energy barrier to ring-flipping from variable-temperature NOESY experiments. The conclusions reached were supported by molecular modeling studies and an NMR spectroscopic investigation of the commercially available germacranolide, parthenolide.

The new sesquiterpene lactone 13-hydroxymethylenedeacetyllaurenobiolide was isolated from the aerial part of Tanacetopsis mucronata S. Koval. (Asteraceae). Its structure was established using spectral data and X-ray structure analysis. The germacranolide macrocycle has the chair-chair conformation with the configuration 1D14, 15D5.

Four new germacrane-type sesquiterpenoids with unsaturated acids as esters at the 8-position, two chlorine atom-containing lactones, 2alpha-acetoxyepitulipinolide, and 12 previously known compounds have been isolated from the MeOH extract of Eupatorium glehni (Compositae) and their structures have been determined on the basis of spectral data analyses.

Nine known sesquiterpene lactones, including four lactucin-type guaianolides, four costuslactone-type guaianolides and one germacranolide, were isolated from roots of Lactuca sibirica (Asteraceae), six of which were glycoside derivatives. The chemosystematic significance of the compounds is discussed in the context of sesquiterpenoids present in roots of the closely related species Lactuca tatarica. A comparison of sesquiterpene lactone profiles indicate that the species can be differentiated on the basis of their germacranolide glycoside compositions.

The extract of Artemisia asiatica herb with antiproliferative activity against four human tumor cell lines (A2780, A431, HeLa, and MCF7) was analyzed by the MTT assay, and bioassay-directed fractionation was carried out in order to identify the compounds responsible for the cytotoxic activity. Guaianolide (1–4), seco-guianolide (5), germacranolide (6) and eudesmanolide sesquiterpenes (7), monoterpenes (8, 9), including the new compound artemisia alcohol glucoside (8), and flavonoids (10–16) were isolated as a result of a multistep chromatographic procedure (CC, CPC, PLC, and gel filtration). The compounds were identified by means of UV, MS, and NMR spectroscopy, including 1H-and 13C-NMR, 1H-1H COSY, NOESY, HSQC, and HMBC experiments. The isolated compounds 1–16 were evaluated for their tumor cell growth-inhibitory activities on a panel of four adherent cancer cell lines, and different types of secondary metabolites were found to be responsible for the cytotoxic effects of the extract. Especially cirsilineol (13), 3β-chloro-4α,10α-dihydroxy-1α,2α-epoxy-5α,7αH-guai-11(13)-en-12,6α-olide (3), and iso-seco-tanapartholide 3-O-methyl ester (5) exerted marked cytotoxic effects against the investigated cell lines, while jaceosidin (12), 6-methoxytricin (15), artecanin (2), and 5,7,4′,5′-tetrahydroxy-6,3′-dimethoxyflavone (14) were moderately active. All the sesquiterpenes and monoterpenes are reported here for the first time from this species, and in the case of artecanin (2), 3α-chloro-4β,10α-dihydroxy-1β,2β-epoxy-5α,7αH-guai-11(13)-en-12,6α-olide (4), ridentin (6), and ridentin B (7), previously unreported NMR spectroscopic data were determined.

Further phytochemical investigation of the aerial parts of Achillea clavennae has resulted in the isolation of three new sesquiterpene lactones: two highly oxygenated germacranolides (1, 2) and the iso-seco-guaianolide 9(R)-acetoxy-3-O-methyl-iso-seco-tanapartholide (3). Eight known compounds were also found, of which 9α-acetoxycanin (5), sintenin (6), and oleanolic acid (7) were detected for the first time. The structures of the isolated compounds were elucidated by combined spectroscopic methods (1D and 2D NMR, HRESIMS, CIMS, and FTIR). While the predominant metabolite germacranolide sintenin (6) was not cytotoxic, the new iso-seco-guaianolide (3) displayed cytotoxicity comparable to that of cisplatin and the lactone apressin (4), inducing partly apoptotic death in human U251 and rat C6 glioma cell lines.

A re-investigation of subaerial parts of Leontodon cichoraceus (Ten.) Sanguin. yielded the new germacrane- type sesquiterpenoid 15-β-D-glucopyranosyl-8- [p-(β-D-glucopyranosyloxy)phenylacetyl]-salonitenolide. The structure was established by APCI mass spectrometry and 1D- and 2D-NMR spectroscopy. A survey by HPLC-DAD and HPLC-MS gave no signs of this compound in 23 other taxa of Leontodon.

Many sesquiterpene lactones (Sls) are known to possess anti-inflammatory activities. To gain further insight into their structure-activity relationships and the molecular mechanism of action, four germacranolide sesquiterpene lactones which differ in the skeleton and the number of reactive centers (4beta,15-epoxy-miller-9E-enolide (1), 15-acetoxy-eremantholide B (2), a mixture of 15-(isovaleroyl)/15-(2-methyl-butyryl)-2alpha-acetoxy-miguanin (3), and 15-(2-hydroxy)-isobutyryloxy-micrantholide (4)) were investigated for their effect on production of proinflammatory cytokines (interleukin-1beta [IL-1beta], IL-6, and tumor necrosis factor-alpha [TNF-alpha]) as well as proliferation of concanavalin A (Con A) and lipopolysaccharide (LPS)-stimulated mouse lymphocytes. Compounds 1 and 3 which possess an alpha-methylene-gamma-lactone function and a conjugated carbonyl group induced a half-maximal inhibition of cytokine synthesis in adherent mouse peritoneal exudate cells at micromolar concentrations (IC(50) 0.69-1.70 microM), while compound 4 which contains only an alpha-methylene-gamma-lactone residue was less active (IC(50) > or 38 microM). Interestingly, compound 2, which carries only a conjugated keto group, displayed a potency similar to those of the bifunctional compounds 1 and 3. All four Sls suppressed proliferation of murine lymphocyte at IC(50) concentrations between 0.22 and 5.03 microM. The rank order of potency was 1 = 2 > 3 > 4. Generally, the growth of LPS-stimulated cells was more strongly influenced than those of Con A-activated lymphocytes. This effect was particularly pronounced with 4. Inhibitory concentrations correlated well with those necessary for inhibition of the transcription factor nuclear factor kappaB (NF-kappaB) observed in a previous investigation. Therefore, it can be assumed that NF-kappaB may be involved in the suppressive effect of Sls on cytokine production and lymphocyte proliferation.

The methanol extract of sub-aerial parts of Hieracium murorum L. gave germacra-7αH-1(10)E,4Z,11­(13)-trien-12,8α-olide-15-oic acid (15 1)-β-D-glucopyranosyl ester (1), a new sesquiterpenoid of the germacrane-type, and two new 4-hydroxybenzyl alcohol derivatives, 4-hydroxy-cinnamomic acid 4-β-D-glucopyranosyloxybenzyl ester (2) and 3-hydroxy-2-[(4-hydroxy-phenyl)-acetoxy]-3-methyl-butyric 4-β-D-glucopyranosyloxybenzyl ester (3). The methanol extract of sub-aerial parts of Crepis bocconi P. D. Sell gave 4-hydroxybenzoic acid 4-β-D-glucopyranosyloxybenzyl ester (4), another new 4-hydroxybenzyl alcohol derivative. The structures of these compounds were established by means of MS and one- and two dimensional-NMR experiments. Copyright © 2001 John Wiley & Sons, Ltd.

Semi-empirical quantum-chemical methods were used to model transannular cyclization of 1(10)E,4E-germacranolide costunolide into eudesmanolides. The conformational states favorable for the transformation and the energy barriers were calculated.

The aerial parts of Centaurea thessala ssp. drakiensis and C. attica ssp. attica afforded, in addition to several known sesquiterpene lactones, two new eudesmanolides, 4-epi-sonchucarpolide and its 8-(3-hydroxy-4-acetoxy-2-methylene-butanoyloxy) derivative and one new eudesmane derivative, named atticin. The in vitro antifungal activity of most compounds was tested against nine fungal species, using the micro-dilution method. All the compounds tested showed great antifungal activity.

From the roots of Crepis mollis, one new and two known guaianolides were isolated together with eight known guaianolide glycosides, one known germacranolide glycoside and two known phenylpropanoids. The structure and relative configuration of the new compound were established as 9alpha-hydroxy-4beta, 15, 11beta, 13-tetrahydro-dehydrozaluzanin C by spectral methods.

Fungicidal activity of 36 natural and synthetic sesquiterpene lactones with guaianolide, trans, trans-germacranolide, cis, cis-germacranolide, melampolide, and eudesmanolide carbon skeletons was evaluated against the phytopathogenic fungi Colletotrichum acutatum, C. fragariae, C. gloeosporioides, Fusarium oxysporum, Botrytis cinerea, and Phomopsis sp. Dose-response data for the active compounds dehydrozaluzanin C, dehydrocostuslactone, 5alpha-hydroxydehydrocostuslacone, costunolide, and zaluzanin C are presented. A new 96-well microbioassay procedure for fast and easy evaluation of antifungal activity was used to compare these compounds with commercial fungicide standards. Some structure-activity conclusions are also presented.

The new germacranolide epi -isocostunolide and two new bisbibenzyls, 2′-(11-hydroxy-1-bibenzyl-oxy)-1′-methoxy-6′,10′,11′-trihydroxy-7′,8′-dihydro-phenanthrene and 2′-(10,11-dihydroxy-1-bibenzyl-oxy)-1′-methoxy-6′,10′,11′-trihydroxy-7′,8′-dihydrophenanthrene, along with the known eudesmanolides, α-cyclocostunolide, brothenolide, nepalensolide A and nepalensolide B, the bisbibenzyls, perrottetin E, perrottetin F, perrottetin G, 7′,8′-dehydroperrottetin F, and the bibenzyls, lunularic acid and lunularin, have been isolated from the neotropical liverwort Frullania convoluta . Their structures were elucidated by NMR spectroscopy.

Microbial transformation of the germacranolide parthenolide using Rhizopus nigricans , Streptomyces fulvissimus and Rhodotorula rubra yielded three new compounds: 11αH-dihydroparthenolide, 9β-hydroxy-11βH-dihydroparthenolide and 14-hydroxy-11βH-dihydroparthenolide. 11βH-dihydroparthenolide was the only common metabolite produced by all microorganisms.

The γ-lactones found in white cypress-pine (Callitris glaucophylla) wood are compounds implicated in termiticidal activity. Distilled oils and solvent extracts from an cypress-pine contained different amounts of γ-lactones. The distilled oils were poor in γ-lactones ( 45%). Oils and extracts contained (-)eudesma-1,4(15),11-triene, β-selinene and α-selinene previously found in other Callitris oils. Six γ-lactones were identified using GC/MS. They were callitrin, dihydrocolumellarin, callitrisin, columellarin, germacranolide and dihydrocallitrisin. Mass spectroscopy indicated three previously unidentified lactones; two were isomers of callitrisin and the third, an isomer of germacranolide. Chiral gas chromatography separated many enantiomers of lower boiling point components of the distilled oil.

The aerial parts of Stevia alpina var. glutinosa afforded, in addition to knownsesquiterpene lactones, two new germacranolides and two new eudesmanolides. The structureswere established mainly by NMR spectroscopy.

Two new neurolenin-type sesquiterpene lactones were found in the leaves of Neurolaena macrocephala Sch. Bip. Ex Hemsl. ( Asteraceae ). These compounds were identified by their NMR spectra as the 8 β -isobutyryloxy- and 8 β - (2-methyl)butyryloxy analogs of neurolenin B. Additionally, the known neurolenins B, C and D and the furanoheliangolide 9a-acetoxy-8 β -isovaleryloxy-calyculatolide were found to be present in this species.

crude F 1 leaf extract displaying significant (>5%) inhibition of PMNL activity, provides further evidence Novel sexual hybrids have been produced between that parthenolide is not the sole determinant of the medicinally-important species T. parthenium (L.) pharmacological activity in the genus Tanacetum. Schultz-Bip. (feverfew) and T. vulgare (L.) Schultz-Bip. (tansy). Morphologically, the F 1 hybrids were more Key words: Feverfew, tansy, sexual hybridization, parthenclosely aligned to feverfew than to tansy, although olide, novel compounds. notable differences were observed in floral and leaf morphologies of the hybrid plants compared to both parental species. Ultrastructurally, the lower Introduction epidermal leaf surfaces of the F 1 hybrids displayed characteristics from both parents, with glandular The genus Tanacetum (L.), formerly Pyrethrum (Zinn), trichome morphology and density similar to that of is a large, poorly defined classification group in the feverfew, but non-glandular trichome density compar- Asteraceae (Compositae) containing 150‐200 species, able to that of tansy. Diploid F 1 (2n=2x=18) hybrids many of which have applications as herbal medicines. and their parental progenitors were analysed biochem- Two of the more common European species of Tanacetum ically, using chromatographic techniques. The bioac- were selected for sexual hybridization, to determine the tive germacranolide, parthenolide, was present in high impact of this process on biochemical and pharmacoconcentrations [1.72±0.16% dry leaf weight (mean logical characteristics of plant extracts. Previous bio±s.d., n=5)] in leaf extracts from feverfew, but to a chemical studies of sexual hybridization in the genus much lesser extent in both tansy and the F 1 hybrids Helianthus of the Asteraceae (Buschmann and Spring, (

The dried roots of Saussurea lappa, called costus roots, are used in the traditional system of medicine for the treatment of cancer. In our investigation for the anticancer constituents from the hexane extract of this plant, a new sesquiterpene (1) was isolated along with the known compounds costunolide (2), beta-cyclocostunolide (3), dihydro costunolide (4) and dehydro costuslactone (5). Their structures were established by the extensive spectroscopic analyses. In addition, costunolide and beta-cyclocostunolide derivatives were synthesized using Michael-type addition reaction of NaOMe to the alpha-methylene-gamma-lactone moiety. All the compounds were tested for their in vitro cytotoxic activity. Compound 1 exhibited potent cytotoxic activity and other compounds displayed moderate activity.

A new germacranolide, inulacappolide (1), was isolated from the EtOH extract of the whole plant of Inula cappa along with 16 known compounds. The structure of inulacappolide was a rare 1(10)-saturated type of germacran-6,12-olide, identified as 2alpha-acetoxy-3beta-hydroxy-9beta-angeloyloxygermacra-4-en-6alpha,12-olide by spectral analysis (IR, HR-ESI/MS, (1)H-NMR, (13)C-NMR, HMQC, HMBC, NOESY). In vitro, it showed antiproliferative effects against human cervical cancer HeLa, human leukemia K562 and human nasopharyngeal carcinoma KB cell lines with IC(50) values of 1.2 microM, 3.8 microM and 5.3 microM, respectively.

In addition to known compounds, the aerial parts of Podachaenium eminens contained the guaianolide named eminensin A, the eudesmanolide eminensin B and podachaenin, a compound formed through esterification of an hydroxyguaianolide by costic acid. Structures of these compounds were established by analysis of their spectroscopic data and, in the case of eminensin A, it was confirmed by X-ray crystallographic analysis.

The minimum inhibitory concentrations (MIC) against Mycobacteriumtuberculosis and M. avium of parthenolide, costunolide, 1 (10)-epoxycostunolide and other germacranolide-type sesquiterpene lactones and derivatives were determined by use of a radiorespirometric bioassay. Structure-activity relationship studies with natural and semisynthetic sesquiterpene lactones suggested that the α -methylene- γ -lactone moiety is an essential, but not sufficient, structural requirement for significant in vitro activity against M. tuberculosis and M. avium .

The leaves and especially the roots of chicory (Cichorium intybus L.) contain high concentrations of bitter sesquiterpene lactones such as the guianolides lactupicrin, lactucin, and 8-deoxylactucin. Eudesmanolides and germacranolides are present in smaller amounts. Their postulated biosynthesis through the mevalonate-farnesyl diphosphate-germacradiene pathway has now been confirmed by the isolation of a (+)-germacrene A synthase from chicory roots. This sesquiterpene cyclase was purified 200-fold using a combination of anion-exchange and dye-ligand chromatography. It has a Km value of 6.6 μm, an estimated molecular mass of 54 kD, and a (broad) pH optimum around 6.7. Germacrene A, the enzymatic product, proved to be much more stable than reported in literature. Its heat-induced Cope rearrangement into (−)-β-elemene was utilized to determine its absolute configuration on an enantioselective gas chromatography column. To our knowledge, until now in sesquiterpene biosynthesis, germacrene A has only been reported as an (postulated) enzyme-bound intermediate, which, instead of being released, is subjected to additional cyclization(s) by the same enzyme that generated it from farnesyl diphosphate. However, in chicory germacrene A is released from the sesquiterpene cyclase. Apparently, subsequent oxidations and/or glucosylation of the germacrane skeleton, together with a germacrene cyclase, determine whether guaiane- or eudesmane-type sesquiterpene lactones are produced.

A new sesquiterpenoid lactone was isolated from terrestrial parts ofArtemisia subchrysolepis Filat. and studied by X-ray diffraction analysis and CD spectroscopy. This compound was called subchrysine and identified as (1R,3S,4E,6R,7S)-3-acetoxy-1-hydroxygernmacra-4,10(14), 11(13)-trien-12,6-olide. Pronounced temperature dependence of the1H and13C NMR spectra of subchrysine was observed. The results of conformational analysis of subchrysine by quantum-chemical (PM3) and molecular mechanics (MMX) methods are also presented.

The aerial parts of Vicoa indica afforded a new sesquiterpene lactone as its acetate (1) the structure and relative stereochemistry of which was established by spectral data including X-ray crystallographic analysis.

The investigation of two Onopordon species afforded, in addition to known sesquiterpene lactones and other constituents, six new germacranolides and a new eudesmanolide. The structures were elucidated by spectroscopic methods.

A new germacranolide, ajanolide A, was isolated from aerial parts ofAjania fruticulosa by means of extraction with CHCl3 and adsorption chromatography. This compound was identified as (1(10)E,3S,4Z,6R,7S,11R)-3-acetoxygermacra-1(10),4-dien-12,6-olide ((1S,7S,10R,13R)-7-acetoxy-4,8,13-trimethyl-11-oxabicyclo[8.3.0]trideca-4(E),8(Z)-dien-12-one) by X-ray diffraction analysis. 2D1H−1H (COSY) and13C−1H (COSY) NMR spectroscopy was used for assigning the1H and13C NMR signals in the spectra of ajanolide A.

An extract of whole plants of Achillea santolina afforded a new guaianolide and a new germacranolide in addition to two known guaianolides and three flavonoids. Structures were elucidated by spectroscopic methods, and the structure of the germacranolide was confirmed by a single crystal X-ray analysis.

The inhibitory effects of whole and fractionated acetone extracts of leaves of four species of Tanacetum were assessed in vitro, using a human polymorphonuclear leucocyte-based bioassay. Biochemical investigation detected the bioactive germacranolide, parthenolide, at high concentrations, in extracts from T. parthenium and T. niveum (1.72% ± 10.16 and 2.62 ± 0.23% leaf dry weight, respectively; n=5). The compound was present at much lower concentrations ( 5%. Such fractions presumably contained compounds that augmented the pharmacological activity of extracts beyond that predicted on the basis of parthenolide content alone, and were responsible, in part, for the pharmacological activity of the extracts lacking parthenolide. These effects on phorbol myristate acetate-induced chemiluminescence suggested the activity of the responsible compound(s) was a result of inhibition of protein kinase C, or subsequent events, in polymorphonuclear leucocyte activation in vitro.

The aerial parts of Artemisia inculta collected in three different locations in Egypt have been chemically investigated. As a result, a new eudesmanolide and a new tetranorsesquiterpene lactone have been isolated, together with several known compounds. The chemical data available suggest the existence of distinct chemotypes for this species, but do not support its identity with other North African members of the genus.

The aerial parts of Artemisia lucentica yielded, in addition to several known compounds, a bicyclic monoterpene ketone, two germacranolides, an eudesmanolide, a 10- epi neudesmanolide, a 2-norelemanolide and three bisabolene derivatives. The stereochemistry of a germacranolide, described as 2α-hydroxyartemorin in a previous investigation of the species, has now been corrected and the compound has been renamed lucentolide.

An extract of whole plants of Urospermum picroides afforded five new germacronolides and germacranolide glycosides. Their structures were elucidated by spectroscopic methods.

From the roots of Lactuca tatarica, one new and two known guaianolides were isolated together with five known guaianolide glycosides, three known germacrolide glycosides and benzyl-β-glucopyranoside. The structure of the new compound was elucidated as 11βH, 13-dihydrolactucin-8-O-p-methoxyphenylacetate by spectral methods.

The structure of 1(10)Z,4Z-germacranolides was studied by the method of molecular mechanics. Possible conformers, the probability of their existence, and barriers to conformational transitions were determined.

The whole plant of Elephantopus scaber afforded the known deoxyelephantopin and isodeoxy-elephantopin, and a new germacranolide sesquiterpene lactone named scabertopin, whose structure and stereo-chemistry were determined by spectroscopic methods and single-crystal X-ray analysis.

The germacranolide 11,13-dihydroridentin, for which the previously unknown S-configuration of the asymmetric center on C-11 was established, was isolated for the first time from Artemisia pontica L.

Three new eudesmenoic acid methyl esters (1-3), as well as five known compounds, including three germacranolides (4-6) and two eudesmanolides (7 and 8), were isolated from the seed oil of Jatropha curcas. The new compounds were elucidated by means of spectroscopic methods, including extensive NMR spectra. In addition, the structure of 8 was confirmed by a single-crystal X-ray diffraction analysis. Among the isolates, compounds 4-6 were the first reported from the genus Jatropha. Using MTS viability assay, the cytotoxicity of compounds 2-8 were evaluated against HL-60, SMMC-7721, A-549, MCF-7, and SW480 human tumor cell lines. Compounds 4 and 5 showed remarkable cytotoxicity against all the tested cell lines with IC50 values from 0.5 to 3.5 mu M, and the new compound 3 displayed selective cytotoxic activity against A-549 cell with an IC50 value of 7.24 mu M, but slight cytotoxicity against HL-60 and MCF-7 with IC50 values of 23.77 and 22.37 mu M, respectively. (C) 2013 Elsevier B.V. All rights reserved.

The structure of 1(10)E,4E-germacranolides was studied by a molecular mechanics method. Possible conformers, the probabilities of their occurrence, and the barriers to conformational transitions were determined.

Isolation, structure elucidation and allelopathic bioassays of 13 sesquiterpene lactones, four of them new, from the sunflower cultivar VYP® are described. Structures of the lactone assigned as 1,2-anhydrido-4,5-dihydroniveusin A, previously isolated from capitate glandular trichomes of Helianthus annuus and of annuithrin are corrected. The effect of a series of aqueous solutions at 10−4–10−9 M of the sesquiterpene lactones was studied on the root and shoot lengths of Lactuca sativa var. nigra, Lepidium sativum, Lycopersicon esculentum, seedlings (dicotyledons) and Hordeum vulgare and Triticum estivum (monocotyledons). The guaianolides generally had no effect on the germination and growth of L. sativum and L. esculentum, except for C-10 epimers 8β-angeloyloxycumambranolide and annoulide G where inhibitory effects were found on the shoot length of L. esculentum. Both exhibit similar activity profiles, the most persistenty active compound on dilution was 8β-angeloyloxycumambranolide with an α-orientated hydroxyl group at C-10. The conformational changes due to functionalization within germacranolides influence principally root and shoot growth. Heliangolides have greater effect on root and shoot length of dicotyledon species, presumably due to conformational flexibility and the presence of electrophylic groups.