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At least 1,207 records · Page 67Linked to original sources
PubMed2003

Two cytotoxic sesquiterpene lactones from the leaves of Xanthium strumarium and their in vitro inhibitory activity on farnesyltransferase.

Two xanthanolide sesquiterpene lactones, 8- epi-xanthatin (1) and 8- epi-xanthatin epoxide (2), isolated from the leaves of Xanthium strumarium (Compositae), demonstrated a significant inhibition on the proliferation of cultured human tumor cells, i. e., A549 (non-small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nervous system) and HCT-15 (colon) in vitro. They were also found to inhibit the farnesylation process of human lamin-B by farnesyltransferase (FTase), in a dose-dependent manner in vitro (IC 50 value was calculated as 64 and 58 microM, respectively). Due to the relatively high concentrations of 1 and 2 required to obtain an FTase inhibition as compared with those necessary for a cytotoxic effect on tumor cells, it remains unclear whether a relationship between these two activities exists.

Alkyl and Aryl Transferases↗
PubMed2004

Flavonoids and a sesquiterpene lactone from Tanacetum microphyllum inhibit anti-inflammatory mediators in LPS-stimulated mouse peritoneal macrophages.

In our ongoing research into anti-inflammatory compounds from Tanacetum microphyllum, four naturally occurring flavonoids (santin, ermanin, centaureidin and 5,3'-dihydroxy-4'-methoxy-7-methoxycarbonylflavonol) and one sesquiterpene lactone (hydroxyachillin) isolated from this plant, were evaluated as potential inhibitors of some macrophage functions involved in the inflammatory process. These five compounds significantly inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E (2) (PGE (2)) in a concentration-dependent manner. In the tumour necrosis factor-alpha (TNF-alpha) assay, only centaureidin and hydroxyachillin significantly inhibited the accumulation of TNF-alpha. These results indicate that these compounds may contribute to the anti-inflammatory properties of T. microphyllum.

Animals↗
PubMed2004

Sesquiterpene lactones in Arnica montana: a rapid analytical method and the effects of flower maturity and simulated mechanical harvesting on quality and yield.

A rapid extraction, clean-up and RPLC procedure suitable for routine quantitative analyses of sesquiterpene lactones (SLs) in Arnica montana is described. Seven SLs were isolated of which tigloyl and methacryloyl esters of helenalin made up over 50 % of the total. This method was applied to analyses of replicated samples of different flower parts, different stages of flower maturity, and herb from different harvest methods. The mean total SL levels were higher in the disk flowers (0.872 % w/w) than the ray flowers (0.712 %), lower in the flower receptacles (0.354 %) and lowest in stems (0.028 %). Relative levels of individual SLs varied significantly between flower parts, especially acetyldihydrohelenalin which had its highest concentration in stems. The total SL contents increased progressively as the flowers matured, from 0.512 % in buds to 0.943 % in withered flowers. Harvesting a range of flower maturities at one time in a simulated mechanical harvest, followed by mechanical separation of low quality stem material gave the same quality as hand harvested A. montana flowers (over 0.8 % total SLs) and the flower yields from the two processes were similar when adjusted for harvesting technique (320 kg dry matter/ha by hand, 295 kg/ha mechanical). Delaying flower harvest until the flower petals had withered greatly improved the SL concentration of the drug.

Arnica↗
PubMed2004

Tucumanin, a beta-hydroxy-gamma-lactone bistetrahydrofuranic acetogenin from Annona cherimolia, is a potent inhibitor of mitochondrial complex I.

A new beta-hydroxy-gamma-methyl-gamma-lactone bistetrahydrofuranic acetogenin, tucumanin, with the infrequent symmetrical threo/trans/threo/trans/threo relative configuration at the tetrahydrofuran rings was isolated from Annona cherimolia (Annonaceae) seeds. The inhibitory potency on the mitochondrial complex I of acetogenins with this relative configuration (tucumanin and asimicin)was compared with that shown by the corresponding pairs with an asymmetrical threo/trans/threo/trans/erythro relative configuration (laherradurin/rolliniastatin-2, and itrabin/molvizarin). All these compounds act as selective inhibitors of mitochondrial complex I in the 0.18 - 1.55 nM range.

Annona↗
PubMed2005

Cytological development and sesquiterpene lactone secretion in capitate glandular trichomes of sunflower.

The secretion of sesquiterpene lactones (STL) in capitate glandular trichomes from the anther appendages of Helianthus annuus L. (Asteraceae) was observed by light and fluorescence microscopy and HPLC analysis. Disk flowers within the sunflower capitulum showed the known ontogenetic progression from the centre to the margin. During development of the florets, the trichomes in the anther appendages secreted their metabolites into the subcuticular secretion storage space in front of the two apical cells. All stages of forming the cuticular globe, from the pre-secretory to the post-secretory phase, could be observed microscopically and secretory activity was simultaneously monitored. Six germacrolides and heliangolides of known structure were selected for quantitative analysis. The increase in STL content during extension of the subcuticular space was monitored by HPLC analysis. Thereby, the start and termination of STL biosynthesis was defined in relation to other developmental stages of floret ontogenesis, particularly, the pollen formation. Part of the secreted material showed autofluorescence which could be attributed to a hydroxy-trimethoxy-flavone, as determined by NMR and mass spectroscopy. The anther trichomes were cytologically and chemically similar to foliar glandular trichomes of sunflower and represent the multicellular capitate glandular trichome type common to many Asteraceae. The ease with which anther trichomes of H. annuus can be harvested and analyzed suggests that they can provide a valuable model system for investigation of STL and flavonoid metabolism in Asteraceae.

Flowers↗
PubMed2005

New sesquiterpene lactones from Arnica tincture prepared from fresh flowerheads of Arnica montana.

Investigation of an ethanolic extract prepared from fresh Arnica montana flowers afforded three new 1,5- trans-guaianolides, of which 11alpha,13-dihydro-2-O-tigloylflorilenalin and the respective 2-O-isovaleryl derivative are reported for the first time. Additionally, three new and one known 2beta-ethoxy-2,3-dihydrohelenalin esters were isolated. GC/MS studies of the extract after a two year storage at 4 degrees C demonstrated that the latter were artefacts that had been formed by addition of ethanol to the cyclopentenone structure of helenalin. Formation of these adducts gave compounds possessing an inhibitory activity comparable to that of 11alpha,13-dihydrohelenalin derivatives in the NF-kappaB EMSA and the IL-8 ELISA in vitro assays as well as in the in vivo croton oil-induced mouse ear edema test for one adduct, namely 2beta-ethoxy-6-O-acetyl-2,3-dihydrohelenalin. As expected, 6-O-(2-methylbutyryl)- and 6-O-methacryloyl-helenalin exhibited a stronger activity in the NF-kappaB EMSA and IL-8 ELISA. Sesquiterpene lactones seem to be the most important NF-kappaB inhibiting compounds in the Arnica extract. Bioguided fractionation using the luciferase reporter gene assay resulted in the isolation of only moderately active compounds, such as 6-acetoxy-2,2-dimethylchroman-4-one and 10-acetoxy-8,9-epoxythymol isobutyrate.

Animals↗
PubMed2005

Cytotoxic activity of some natural and synthetic sesquiterpene lactones.

Several natural and synthetic sesquiterpene lactones with different skeletons were tested and found to be active against nine cancer cell lines. Elemane, heliangolane and their hydroxy analogues 9 and 10, all containing an alpha,beta-unsaturated aldehyde substituent, were the most potent compounds.

Antineoplastic Agents, Phytogenic↗
PubMed2006

12-Acetoxyhawtriwaic acid lactone, a diterpene from Egletes viscosa, attenuates capsaicin-induced ear edema and hindpaw nociception in mice: possible mechanisms.

The diterpene, 12-acetoxyhawtriwaic acid lactone (AHAL, tanabalin) isolated from the flower buds of Egletes viscosa Less. (Asteraceae) was evaluated on capsaicin-induced ear edema and hindpaw nociception in mice. AHAL (12.5, 25 and 50 mg/kg, P. O.) significantly attenuated the ear edema response to topically applied capsaicin (250 microg), in a dose-related manner. At similar doses, AHAL also suppressed the nocifensive paw-licking behavior induced by intraplantar injection of capsaicin (1.6 microg). These responses to capsaicin were also greatly inhibited by ruthenium red (3 mg/kg, S. C.), a non-competitive capsaicin receptor (TRPV1) antagonist. The anti-edema effect of AHAL (50 mg/kg) seems unrelated to either blockade of mast cell degranulation or to histamine and serotonin receptor antagonism since AHAL did not modify the paw edema response induced by intraplantar injections of compound 48/80, histamine or serotonin. However, the hindpaw edema induced by substance P and vascular permeability increase induced by intraperitoneal acetic acid were significantly suppressed by AHAL. The antinociceptive effect of AHAL (50 mg/kg) was unaffected by naloxone pretreatment but was significantly antagonized by theophylline and glibenclamide, the respective blockers of adenosine and K(ATP)-channels. AHAL (50 mg/kg, P. O.) did not impair the ambulation or motor coordination of mice in open-field and rota-rod tests. These data suggest that AHAL inhibits acute neurogenic inflammation possibly involving capsaicin-sensitive TRPV1-receptors, endogenous adenosine and ATP-sensitive potassium channels.

Analgesics↗
PubMed2006

Free radical-scavenging delta-lactones from Boletus calopus.

The methanol extracts from the fruiting body of the mushroom Boletus calopus showed free radical-scavenging activity. Bioactivity-guided fractionation of the methanol extracts led to a new hydroxylated calopin named calopin B, along with the known delta-lactones calopin and cyclocalopin A. The structure of the new calopin analogue was elucidated by spectroscopic methods. All compounds showed potent free radical-scavenging activity against superoxide, DPPH, and ABTS radicals with IC (50) values of 1.2 - 5.4 microg/mL.

Agaricales↗
PubMed1998

Study of three sesquiterpene lactones from Tithonia diversifolia on their anti-inflammatory activity using the transcription factor NF-kappa B and enzymes of the arachidonic acid pathway as targets.

In Central America leaf extracts from the Asteraceae Tithonia diversifolia are used externally for the treatment of haematomas and wounds. Therefore, the main sesquiterpene lactones (Sls) of this species growing in Costa Rica, diversifolin (1), diversifolin methyl ether (2), and tirotundin (3), were studied for their anti-inflammatory activity. We determined whether these compounds inhibit cyclooxygenase-I, phospholipase A2, or the transcription factor NF-kappa B. Here we show that these Sls do not influence the enzymes of the arachidonic acid pathway, but inhibit the activation of NF-kappa B. Thereby, the synthesis of inflammatory mediators such as cytokines and chemokines is reduced. Our results indicate that the inhibitory activity of compounds 1-3 is due to alkylation of cysteine residues, which are probably located in the DNA binding domain of NF-kappa B. The Sls were also studied for their antibacterial activity, but only Sl 1 was moderately active against Bacillus subtilis in the agar plate diffusion test.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Inhibitory effect of sesquiterpene lactones from Saussurea lappa on tumor necrosis factor-alpha production in murine macrophage-like cells.

Total methanol extract of Saussurea lappa radix (Compositae) showed potent inhibitory effect on the production of tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, in murine macrophage-like cell (RAW264.7 cells) in our previous screening studies on 120 Korean medicinal plants. The activity-guided purification of the plant resulted in the isolation of three components. The chemical structures of the components isolated were established by spectroscopic analyses as sesquiterpene lactones [cynaropicrin (1), reynosin (2), and santamarine (3)]. These three compounds inhibited TNF-alpha production in a dose-dependent manner. The molar concentrations of cynaropicrin, reynosin, and santamarine producing 50% inhibition (IC50) of TNF-alpha production were 2.86 micrograms/ml (8.24 microM), 21.7 micrograms/ml (87.4 microM), and 26.2 micrograms/ml (105 microM), respectively. However, treatment with sulphydryl (SH) compounds such as L-cysteine, dithiothreitol, and 2-mercaptoethanol abrogated the inhibitory effect of cynaropicrin on TNF-alpha production. Therefore, we conclude that the principal inhibitory component of Saussurea lappa is cynaropicrin and its inhibitory effect is mediated through conjugation with SH-groups of target proteins.

Animals↗
PubMed1998

Artemisinin-derived sesquiterpene lactones as potential antitumour compounds: cytotoxic action against bone marrow and tumour cells.

We determined the in vitro cytotoxic activity of the sesquiterpene lactone endoperoxide artemisinin (1) and some chemically prepared derivatives, which have been found to display cytotoxicity to cloned murine Ehrlich ascites tumour (EAT) cells and human HeLa cells and against murine bone marrow using a clonogenic assay for committed progenitor cells of the granulocyte-monocyte lineage (CFU-GM assay). Comparing artemisinin (1) to deoxyartemisinin (2), the endoperoxide group appeared to play a role in cytotoxicity to CFU-GM cells. Dimers of dihydroartemisinin and dihydrodeoxyartemisinin revealed that the stereochemistry of the ether linkage of the dimers was a more important determinant for this cytotoxic activity. The nonsymmetrical dimer of dihydroartemisinin (3) and the corresponding endoperoxide-lacking dimer of dihydrodeoxyartemisinin (5) were equally cytotoxic to CFU-GM cells. Despite the differences between both systems, it may be stated that most compounds displayed higher cytotoxicity to CFU-GM cells than to EAT cells. Dimers of dihydroartemisinin (3, 4) were selected as potential antitumour compounds and subjected to the National Cancer Institute drug-screening programme consisting of about sixty human cancer cell lines derived from nine different tissues. Both compounds displayed the same specific cytotoxicity pattern. Throughout the screen dimer 3 was more active than 4.

Animals↗
PubMed1998

Antimycobacterial matricaria esters and lactones from Astereae species.

Six matricaria esters (MEs) and two matricaria lactones (MLs), isolated from members of the tribe Astereae (Asteraceae), were tested against Mycobacterium tuberculosis and M. avium, using a radiorespirometric bioassay. (2Z,8Z)-ME and (2E-8Z)-ME gave minimum inhibitory concentrations (MICs) of 50 micrograms ml-1 against M. tuberculosis and respective MICs of 25 and 50 micrograms ml-1 against M. avium. The (4Z,8Z)-ML, (2Z)-8-dehydro-ME and (2Z,8Z)-10-angeloyloxy-(2Z,8Z)-ME showed respective MICs of 12.5, 25, 25 micrograms ml-1 against M. tuberculosis and MICs of 50, 25, 25 micrograms ml-1 against M. avium, respectively. The MICs of (2Z,8Z)-10-tigloyloxy-ME and (2E,8Z)-10-angeloyloxy-ME and (4E,8Z)-ML ranged from 50 to > 100 micrograms ml-1 against both pathogenic mycobacteria.

Antitubercular Agents↗
PubMed1996

Antiplasmodial activities and cytotoxic effects of aqueous extracts and sesquiterpene lactones from Neurolaena lobata.

Aqueous and lipophilic extracts of Neurolaena lobata (Asteraceae), obtained from Guatemala, were tested against Plasmodium falciparum in vitro. Moreover, sesquiterpene lactones, of the germacranolide and furanoheliangolide type, isolated from N. lobata, were shown to be active against P. falciparum in vitro. In addition to their antiplasmodial activity, their cytotoxic effects on human carcinoma cell lines were evaluated. Structure-activity relationships are discussed.

Animals↗
PubMed1996

Cytotoxic and antibacterial activities of sesquiterpene lactones isolated from Tanacetum praeteritum subsp. praeteritum.

Ten sesquiterpene lactones and one sesquiterpene isolated from Tanacetum praeteritum subsp. praeteritum: 1 alpha, 6 alpha -dihydroxyisocostic acid methyl ester (2), 1 alpha-hydroxy-1-deoxoarglanine (3), douglanin (5), santamarin (6), reynosin (7), 1-epitatridin B (8), ludovicin A (10), armexin (12), armefolin (13), armexifolin (14), and 3 alpha-hydroxyreynosin (15) were tested against the human lung carcinoma cell line GLC4 and the colorectal cancer cell line COLO 320 as well as against the bacteria Bacillus subtilis, Staphylococcus aureus, Proteus mirabilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus, beta-hemolytic Streptococcus, and the yeast Candida albicans. In addition, two germacranolides tatridin A (16) and tamirin (17) were included in the study. All compounds showed cytotoxic activity (IC50 = 124 microM) but most of them were not effective in the antimicrobial tests.

Anti-Bacterial Agents↗
PubMed1995

Recent studies on the zoopharmacognosy, pharmacology and neurotoxicology of sesquiterpene lactones.

Aspects of recent research on the biological activities of sesquiterpene lactones (SQLs) are presented. Several SQLs have been identified as important constituents of plants consumed by animals for presumed medicinal value and is a focus of research in zoopharmacognosy. Recent in vivo antitumor studies with parthenin and eupatoriopicrin are discussed as well as the reports of the antiulcer activity of dehydroleucodin. Helenalin has recently been reported to have cardiotonic activity. Research on the neurotoxicity of repin, a compound reported to cause a Parkinson's-like disease in horses, is also highlighted.

Animals↗
PubMed1990

Inhibition of leukotriene and platelet activating factor synthesis in leukocytes by the sesquiterpene lactone scandenolide.

The sesquiterpene lactone scandenolide, isolated from the Philippines medicinal plant Mikania cordata, at a dose of 100 microM completely inhibited whole blood chemiluminescence in response to the activators PMA and zymosan. In isolated inflammatory rat leukocytes this compound inhibited both leukotriene B4 and 5-HETE production with IC50 of 15 microM and 30 microM, respectively. The formation of the cyclooxygenase product thromboxane B2 was not inhibited in the concentration range 10 to 200 microM of scandenolide. The formation of the potent inflammatory mediator platelet activating factor (PAF) was suppressed by microM concentrations of scandenolide with an IC50 of less than 20 microM. The presence of a compound in M. cordata which inhibits some of the inflammatory mediators such as leukotrienes and PAF may explain at least in part some of its medicinal properties.

Animals↗