Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LACTONES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources
PubMed2005

Asymmetric synthesis, stereochemistry and rearrangement reactions of naturally occurring 7'-hydroxylignano-9,9'-lactones.

The asymmetric synthesis of a series of (7'S,8R,8'R)-7'-hydroxylignano-9,9'-lactones is presented, among them the mammalian lignan (7'S)-hydroxyenterolactone and (7'S)-parabenzlactone, allowing the stereochemistry of natural occurring (-)-parabenzlactone to be re-assigned. A hydroxylactone rearrangement and its possible mechanisms are discussed. Finally a brief survey of the current naming and numbering variants of 7'-hydroxylignano-9,9'-lactones is presented, along with a suggestion for harmonization of the nomenclature.

Animals↗
PubMed2001

Cytotoxic sesquiterpene lactones mediate their death-inducing effect in leukemia T cells by triggering apoptosis.

Cytotoxicity is a well characterized property of sesquiterpene lactones. In the present study, the question was addressed whether sesquiterpene lactones mediate their cytotoxic effect by triggering apoptosis. Four compounds, ambrosin, alantolactone, hymenin and helenalin were shown to induce apoptosis in Jurkat leukemia T cells as judged by cell morphology, the appearance of apoptotic nuclei as well as the translocation of phosphatidylserine to the outer surface of the cell membrane.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Cytotoxic sesquiterpene lactones from Carpesium abrotanoides.

Eight sesquiterpene lactones, 4 alpha,5 alpha-epoxy-10 alpha,14-dihydro-inuviscolide (1), 2,3-dihydroaromomaticin (2), carpesiolin (3), carabrone (4), carabrol (5), telekin (6), ivalin (7) and 11,13-didehydroivaxillin (8), were isolated from the aerial parts of Carpesium abrotanoides Linne (Compositae). In vitro cytotoxicity testing was carried out against L1210, A549, SK-OV-3, SK-MEL-2, XF-498 and HCT-15 tumor cell lines. Sesquiterpene lactone compounds 1 - 8 showed significant cytotoxic activity (ED50 values, < 20 microM) against all tumor call lines tested. Among these compounds, 4 alpha,5 alpha-epoxy-10 alpha,14-dihydro-inuviscolide (1), 2,3-dihydroaromomaticin (2), telekin (6) and ivalin (7) showed cytotoxic activity (ED50, < 10 microM) comparable to that of cisplatin.

Animals↗
PubMed2004

Eremophilane sesquiterpene lactones from Ligularia virgaurea ssp. oligocephala.

From an extract of the whole plant of Ligularia virgaurea ssp. oligocephala, three new eremophilane sesquiterpene lactones, 10alpha-hydroxy-1-oxoeremophila-7(11),8(9)-dien-12,8-olide (1), 6alpha,10alpha-dihydroxy-1-oxoeremophila-7(11),8(9)-dien-12,8-olide (2), 6beta,10beta-dihydroxyeremophila-7(11),8(9)-dien-12,8-olide (3), as well as four known sesquiterpene lactones with the same carbon skeleton, named toluccanolides A-C (4, 5, 7) and 6beta-hydroxy-8alpha-methoxyeremophila-1(10),7(11)-dien-12,8beta-olide (6) were isolated. Their structures were elucidated by spectroscopic methods including intensive 2D NMR techniques (gCOSY, gHMQC, gHMBC and 1H-1H NOESY for 2) and HR-ESI-MS.

Asteraceae↗
PubMed2005

Phthalide Lactones from Ligusticum chuanxiong inhibit lipopolysaccharide-induced TNF-alpha production and TNF-alpha-mediated NF-kappaB Activation.

The dried rhizome of Ligusticum chuanxiong Hort. (Umbelliferae) is a traditional Chinese medicine (TCM) herb for the prevention and treatment of inflammatory and cardiovascular diseases. However, the role of phthalide lactones from Ligusticum chuanxiong in the therapeutic actions is not yet fully understood. In the present study, two phthalide lactones from the herb, Z-ligustilide and senkyunolide A, were identified and characterized as inhibitors of lipopolysaccharide (LPS)-induced TNF-alpha production in monocytes. The results of gene expression studies showed that the observed TNF-alpha suppression was related to their inhibitory activity on TNF-alpha mRNA transcription. Furthermore, the two phthalides exhibited significant suppressive effects on TNF-alpha-mediated nuclear factor-kappaB (NF-kappaB) activation in reporter gene assays. Taken together, the results suggest that Z-ligustilide and senkyunolide A may have potential applications in the treatment of inflammation and related diseases based on their inhibitory activity on TNF-alpha production and TNF-alpha bioactivity. New insights into the therapeutic basis of the TCM herb, Ligusticum chuanxiong, are presented.

Benzofurans↗
PubMed1993

Feverfew and vascular smooth muscle: extracts from fresh and dried plants show opposing pharmacological profiles, dependent upon sesquiterpene lactone content.

Preparations of fresh or dried feverfew (Chrysanthemum parthenium) are widely consumed in the U.K. as a remedy for arthritis and migraine, but the pharmacological basis for this has not been established. We have, therefore, compared the properties of extracts of fresh plants with those of dried powdered leaves available commercially from health food shops. The two extracts differed radically in their content of alpha-methylbutyrolactones and in their pharmacological profile when tested in vitro on the rabbit aortic ring and rat anococcygeus preparations. Extracts of fresh leaves caused does- and time-dependent inhibition of the contractile responses of aortic rings to all receptor-acting agonists so far tested; the effects were irreversible and may represent a toxic modification of post-receptor contractile function in the smooth muscle. The presence of potentially -SH reactive parthenolide and other sesquiterpene alphamethylenebutyrolactones in these extracts, and the close parallelism of the actions of pure parthenolide, suggest that the inhibitory effects are due to these compounds. In contrast , chloroform extracts of dried powdered leaves were not inhibitory but themselves elicited potent and sustained contractions of aortic smooth muscle that were not antagonised by ketanserin (5-HT2 receptor antagonist). These extracts did not contain parthenolide or butyrolactones according to a chemical-HPLC assay, We conclude that there are marked differences in the pharmacological potency and profiles between preparations from fresh and dried feverfew and that this may relate to their lactone content. As the effects of the lactones are potentially toxic, it will be necessary to compare the clinical profiles and side effects of preparations obtained from the two sources.

Animals↗
PubMed1997

Lactacystin and clasto-lactacystin beta-lactone modify multiple proteasome beta-subunits and inhibit intracellular protein degradation and major histocompatibility complex class I antigen presentation.

The antibiotic lactacystin was reported to covalently modify beta-subunit X of the mammalian 20 S proteasome and inhibit several of its peptidase activities. However, we demonstrate that [3H]lactacystin treatment modifies all the proteasome's catalytic beta-subunits. Lactacystin and its more potent derivative beta-lactone irreversibly inhibit protein breakdown and the chymotryptic, tryptic, and peptidylglutamyl activities of purified 20 S and 26 S particles, although at different rates. Exposure to these agents for 1 to 2 h reduced the degradation of short- and long-lived proteins in four different mammalian cell lines. Unlike peptide aldehyde inhibitors, lactacystin and the beta-lactone do not inhibit lysosomal degradation of an endocytosed protein. These agents block class I antigen presentation of a model protein, ovalbumin (synthesized endogenously or loaded exogenously), but do not affect presentation of the peptide epitope SIINFEKL, which does not require proteolysis for presentation. Generation of most peptides required for formation of stable class I heterodimers is also inhibited. Because these agents inhibited protein breakdown and antigen presentation similarly in interferon-gamma-treated cells (where proteasomes contain LMP2 and LMP7 subunits in place of X and Y), all beta-subunits must be affected similarly. These findings confirm our prior conclusions that proteasomes catalyze the bulk of protein breakdown in mammalian cells and generate the majority of class I-bound epitopes for immune recognition.

Acetylcysteine↗
PubMed1998

Sesquiterpene lactones specifically inhibit activation of NF-kappa B by preventing the degradation of I kappa B-alpha and I kappa B-beta.

Extracts from certain Mexican Indian medicinal plants used in traditional indigenous medicine for the treatment of inflammations contain sequiterpene lactones (SLs), which specifically inhibit the transcription factor NF-kappa B (Bork, P. M., Schmitz, M. L., Kuhnt, M., Escher, C., and Heinrich, M. (1997) FEBS Lett. 402, 85-90). Here we show that SLs prevented the activation of NF-kappa B by different stimuli such as phorbol esters, tumor necrosis factor-alpha, ligation of the T-cell receptor, and hydrogen peroxide in various cell types. Treatment of cells with SLs prevented the induced degradation of I kappa B-alpha and I kappa B-beta by all these stimuli, suggesting that they interfere with a rather common step in the activation of NF-kappa B. SLs did neither interfere with DNA binding activity of activated NF-kappa B nor with the activity of the protein tyrosine kinases p59fyn and p60arc. Micromolar amounts of SLs prevented the induced expression of the NF-kappa B target gene intracellular adhesion molecule 1. Inhibition of NF-kappa B by SLs resulted in an enhanced cell killing of murine fibroblast cells by tumor necrosis factor-alpha. SLs lacking an exomethylene group in conjugation with the lactone function displayed no inhibitory activity on NF-kappa B. The analysis of the cellular redox state by fluorescence-activated cell sorter showed that the SLs had no direct or indirect anti-oxidant properties.

Animals↗
PubMed2001

A new sesquiterpene lactone from Tsoongiodendron odorum Chun.

A new sesquiterpene lactone (1) was obtained from the cytotoxic fraction of 95% ethanol extract of root barks of Tsoongiodendron odorum Chun together with two known sesquiterpene lactones, costunolide (2) and parthenolide (3). The structure of 1 was elucidated as 5alpha, 6alpha, 7beta, 10beta- 11alpha, 13-dihydro-4(15)-eudesmene-12, 6-olide on the basis of chemical and spectral evidence including X-ray diffraction analysis. Costunolide showed cytotoxic activity against human leukemia (HL-60) cell line. Parthenolide showed promising cytotoxic activities in vitro against HCT-8, Bel-7402, SKOV3, KB, HELA and EJ cell lines. Also, the cytotoxic ethyl acetate fraction of ethanol extract of the root barks from which three chemical components were isolated showed promising cytotoxic activities in vitro against KB, BGC-823, Bel-7402, HCT-8, HL-60 cell lines.

Antineoplastic Agents, Phytogenic↗
PubMed1976

Lactones in foods.

Lactones represent another important class of flavor compounds that have been found in a wide variety of foods although traditionally they have been mainly associated with dairy products. This review summarizes their occurrences in foods along with their formation pathways, sensory properties, and isolation, identification, and synthesis techniques specific to lactones associated with food flavor.

Alcohols↗
PubMed1998

Enantiomer analysis of chiral lactones in foods by on-line coupled reversed-phase liquid chromatography-gas chromatography.

A new application is proposed for the on-line coupling of reversed-phase liquid chromatography to gas chromatography (RPLC-GC) that allows the GC chirospecific analysis of gamma-lactones in fruits and commercially available fruit-containing products. The use of a programmed temperature vaporizer as an interface with the system makes the transfer of large volume fractions (i.e., 2520 microL) of aqueous eluents from LC to GC possible (speed of sample transfer, 1800 microL/min). Relative standard deviations obtained for the investigated lactones under the experimental conditions vary from 7 to 14%. The described system enlarges the LC-GC application field and overcomes the limitations reported thus far concerning the use of typical normal-phase eluents (i.e., the transfer of rather small volume fractions at low speeds of sample introduction).

Chromatography, Gas↗
PubMed2000

N-acyl homoserine lactone binding to the CarR receptor determines quorum-sensing specificity in Erwinia.

Quorum sensing via an N-acyl homoserine lactone (HSL) pheromone controls the biosynthesis of a carbapenem antibiotic in Erwinia carotovora. Transcription of the carbapenem biosynthetic genes is dependent on the LuxR-type activator protein, CarR. Equilibrium binding of a range of HSL molecules, which are thought to activate CarR to bind to its DNA target sequence, was examined using fluorescence quenching, DNA bandshift analysis, limited proteolysis and reporter gene assays. CarR bound the most physiologically relevant ligand, N-(3-oxohexanoyl)-L-homoserine lactone, with a stoichiometry of two molecules of ligand per dimer of protein and a dissociation constant of 1.8 microM, in good agreement with the concentration of HSL required to activate carbapenem production in vivo. In the presence of HSL, CarR formed a very high molecular weight complex with its target DNA, indicating that the ligand causes the protein to multimerize. Chemical cross-linking analysis supported this interpretation. Our data show that the ability of a given HSL to facilitate CarR binding to its target DNA sequence is directly proportional to the affinity of the HSL for the protein.

Bacterial Proteins↗
PubMed2001

Transgenic plants producing the bacterial pheromone N-acyl-homoserine lactone exhibit enhanced resistance to the bacterial phytopathogen Erwinia carotovora.

Bacterial pheromones, mainly different homoserine lactones, are central to a number of bacterial signaling processes, including those involved in plant pathogenicity. We previously demonstrated that N-oxoacyl-homoserine lactone (OHL) is essential for quorum sensing in the soft-rot phytopathogen Erwinia carotovora. In this pathogen, OHL controls the coordinate activation of genes encoding the main virulence determinants, extracellular plant cell wall degrading enzymes (PCWDEs), in a cell density-dependent manner. We suggest that E. carotovora employ quorum sensing to avoid the premature production of PCWDEs and subsequent activation of plant defense responses. To test whether modulating this sensory system would affect the outcome of a plant-pathogen interaction, we generated transgenic tobacco, producing OHL. This was accomplished by ectopic expression in tobacco of the E. carotovora gene expI, which is responsible for OHL biosynthesis. We show that expI-positive transgenic tobacco lines produced the active pheromone and partially complemented the avirulent phenotype of expI mutants. The OHL-producing tobacco lines exhibited enhanced resistance to infection by wild-type E. carotovora. The results were confirmed by exogenous addition of OHL to wild-type plants, which also resulted in increased resistance to E. carotovora.

4-Butyrolactone↗
PubMed1997

Quorum sensing and Chromobacterium violaceum: exploitation of violacein production and inhibition for the detection of N-acylhomoserine lactones.

Quorum sensing relies upon the interaction of a diffusible signal molecule with a transcriptional activator protein to couple gene expression with cell population density. In Gram-negative bacteria, such signal molecules are usually N-acylhomoserine lactones (AHLs) which differ in the structure of their N-acyl side chains. Chromobacterium violaceum, a Gram-negative bacterium commonly found in soil and water, produces the characteristic purple pigment violacein. Previously the authors described a violacein-negative, mini-Tn5 mutant of C. violaceum (CV026) in which pigment production can be restored by incubation with supernatants from the wild-type strain. To develop this mutant as a general biosensor for AHLs, the natural C. violaceum AHL molecule was first chemically characterized. By using solvent extraction, HPLC and mass spectrometry, a single AHL, N-hexanoyl-L-homoserine lactone (HHL), was identified in wild-type C. violaceum culture supernatants which was absent from CV026. Since the production of violacein constitutes a simple assay for the detection of AHLs, we explored the ability of CV026 to respond to a series of synthetic AHL and N-acylhomocysteine thiolactone (AHT) analogues. In CV026, violacein is inducible by all the AHL and AHT compounds evaluated with N-acyl side chains from C4 to C8 in length, with varying degrees of sensitivity. Although AHL compounds with N-acyl side chains from C10 to C14 are unable to induce violacein production, if an activating AHL (e.g. HHL) is incorporated into the agar, these long-chain AHLs can be detected by their ability to inhibit violacein production. The versatility of CV026 in facilitating detection of AHL mixtures extracted from culture supernatants and separated by thin-layer chromatography is also demonstrated. These simple bioassays employing CV026 thus greatly extend the ability to detect a wide spectrum of AHL signal molecules.

Chromobacterium↗
PubMed1999

Oocydin A, a chlorinated macrocyclic lactone with potent anti-oomycete activity from Serratia marcescens.

A unique chlorinated macrocyclic lactone, termed oocydin A, was isolated from a strain of Serratia marcescens growing as an epiphyte on Rhyncholacis pedicillata, an aquatic plant native to the Carrao river of the Venezuelan-Guyanan region of South America. The lactone has a molecular mass of 470 Da, and contains one atom of chlorine, a carboxyl group and a tetrahydrofuran ring internal to a larger macrocyclic ring. MICs of approximately 0.03 microg ml(-1) were noted for oocydin A against such phytopathogenic oomycetes as Pythium ultimum, Phytophthora parasitica, Phytophthora cinnamomi and Phytophthora citrophora. With regard to the true fungi, oocydin A had either minimal or no effect against certain Fungi Imperfecti (including several pathogens of humans), two ascomycetes and a basidiomycete. Oocydin A may have potential as an antimycotic in agricultural applications and especially for crop protection.

Antifungal Agents↗
PubMed1977

Studies on the partial synthesis of protein analogs by direct coupling to terminal homoserine lactone derivatives. Experiments with basic pancreatic trypsin inhibitor.

Treatment of basic pancreatic trypsin inhibitor (BPTI, I) with cyanogen bromide smoothly yields the chain cleaved derivative II. The utility of the seco-lactone (II) in the partial synthesis of protein analogues has been investigated. It is shown that the homoserine lactone ring is sufficiently reactive to combine directly with the radiolabelled synthetic peptide glycylglycylanine t-butyl ester in both aqueous and non-aqueous solution, leading to a BPTI analogue which has been purified and characterized.

Cyanogen Bromide↗
PubMed1969

Allergenic component of a liverwort: a sesquiterpene lactone.

Frullania spp. (Hepaticae, Jungermanniales) are agents of allergies. Extraction and fractionation of Frullania tamarisci has given, as the only allergenic component isolated, a levorotatory crystalline sutbstance, the structure of which is demonstrated. It is a sesquiterpene lactone. The racemic (+/-) form is isolated from a mixed sample of Frullania tamarisci and Frullania dilatata; the dextrorotatory form, from Frullania dilatata. The observed allergenic properties are shared by some other-sesquiterpene lactones.

Chromatography, Gel↗