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PubMed2005

The isolation and structure elucidation of a new sesquiterpene lactone from the poisonous plant Coriaria japonica (Coriariaceae).

A new sesquiterpene lactone named coriarin was isolated from achenes (seeds) of Coriaria japonica (Coriariaceae) along with known constituents tutin, dihydrotutin and corianin, and its structure was deduced on a spectroscopic basis. The structure of coriarin was finally confirmed by the base-catalized chemical conversion of tutin into coriarin, in which the lactone ring linkage was transposed from C-3 to C-2. Chemical investigation of sarcocarps was also undertaken in parallel, but neither sesquiterpene lactones nor related constituents were obtained. The results indicate that sesquiterpene lactones occur only in achenes of C. japonica berry, as is the case in other Coriaria species.

Lactones↗
PubMed2006

New A-ring lactone triterpenoid saponins from the roots of Platycodon grandiflorum.

Three new A-ring lactone triterpenoid saponins, platycoside M-1 [3-O-beta-D-glucopyranosyl platycogenic acid A lactone], platycoside M-2 [3-O-beta-D-glucopyranosyl platycogenic acid A lactone 28-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], and platycoside M-3 [3-O-beta-D-glucopyranosyl platycogenic acid A lactone 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], were isolated from the roots of Platycodon grandiflorum A. DC. Their chemical structures were elucidated on the basis of their spectral data and chemical evidence.

Lactones↗
PubMed2006

The fumigant and repellent activity of aliphatic lactones against Pediculus humanus capitis (Anoplura: Pediculidae).

New alternative insecticides are necessary for the chemical control of head lice. In this study the fumigant knockdown time 50% (KT50) and repellency index (RI) of three aliphatic lactones was compared with two essential oils and DDVP, against permethrin-resistance Pediculus humanus capitis from Argentina. In the fumigant assay, none of the lactones were effective compared to the highest activity of eucalyptus (KT50 15.53 m). In the repellency test, the three lactones were equally or more effective (RI ranging from 60.50 to 76.68) than the positive control (piperonal). These lactones are promising as head lice repellents.

Animals↗
PubMed2005

The trypanocidal effect of sesquiterpene lactones helenalin and mexicanin on cultured epimastigotes.

Sesquiterpene lactones constitute a large group of biologically active compounds obtained from plants. The lactones, mexicanin (MXN) and helenalin (HLN), were reported recently as active against the infective form of Trypanosoma cruzi. In this work, we studied the effects of these compounds on the growth and viability of the noninfective epimastigote, to compare the sensitivity of the 2 stages and to characterize their actions. Both compounds were cytotoxic to the parasites, with HLN (inhibitory concentration 50% [IC50] 1.9 +/- 0.08 microM) more potent than MXN (IC50 3.8 +/- 0.19 microM) and the typanocidal drug, benznidazole (IC50 8.6 +/- 2.5 microM). The results showed that epimastigotes are less sensitive than trypomastigotes to the compounds. The trypanocidal effect of these lactones, irreversible after 12-hr exposure, was not reversed by the reducing agents dithiotreitol or beta-mercaptoethanol. Ultrastructurally, we observed cytoplasmic vacuolization and nuclear disorganization. Although concentrations between 0.5 and 1.5 microM of the drugs were not lethal to the parasites, epimastigotes became thinner and their nuclei became more pycnotic after exposure. We conclude that MXN and HLN are deleterious for T. cruzi epimastigotes and that their mechanism of action is different than that of the related lactone, dehydroleucodine.

Animals↗
PubMed1993

Perturbation of glutathione status and generation of oxidative stress in mouse skin following application of contact allergenic sesquiterpene lactones and isothiocyanates.

1. The sensitizing or non-sensitizing status of selected sesquiterpene lactones and isothiocyanates was confirmed in mouse by open epicutaneous application. 2. Glutathione status of mouse skin was determined 12 h after lactone/isothiocyanate application; glutathione S-transferase activity also was determined 12 h after lactone application. 3. NAD(P)H utilization by rat liver microsomal preparations exposed to the sesquiterpene lactones and isothiocyanates was measured. 4. A correlation was observed between sensitizing status and the ability to perturb glutathione status, to induce glutathione S-transferase activity, and to stimulate NAD(P)H utilization. 5. It was concluded that sensitizing sesquiterpene lactones and isothiocyanates could induce oxidative stress in mouse skin, possibly as a result of their reductive metabolism.

Administration, Cutaneous↗
PubMed2001

Purification and properties of L-gulono-1,4-lactone oxidase from Grifola frondosa.

L-Gulono-1,4-lactone oxidase activity was detected in G. frondosa: therefore its properties were studied after purification. A 766-fold purified preparation of the enzyme from fresh fruit bodies was obtained by means of a seven-step procedure, the overall yield being 14%. The purified enzyme gave a single band on polyacrylamide gel electrophoresis and its absorption spectrum exhibited the characteristic of a flavoenzyme. The enzyme produced L-ascorbic acid and H2O2, with L-gulono-1,4-lactone (GL) as the substrate and oxygen as the electron acceptor, and was optimally active at around pH 7.0 and 45 degrees C. Its molecular mass was determined to be 250 kDa on gel filtration, while the dissociated enzyme exhibited a molecular mass of 69 kDa on SDS-polyacrylamide gel electrophoresis, but the true molecular weight is unknown because of the trypsin treatment in the purification process. The apparent Km value for GL was 24+/-1 mM. Its substrate specificity was extremely high and, assuming that for GL to be 100, the following results were obtained: D-mannono-, 25: D-glucono-, 4; L-idono-, 3; L-galactono-1,4-lactone, 2; and 15 other lactones tested, 0. It is presumed that this enzyme is similar to animal GL-oxidase, ascomycetes D-arabinonolactone oxidase, etc.

Agaricales↗
PubMed2004

[Studies on the cell growth, differentiation and terpene lactone accumulation in Ginkgo biloba cell suspension cultures].

To provide supports for Ginkgo biloba cell engineering for production of Terpene lactones (Ginkgolides and bilobalide), the cell suspension were established from calli induced from zygote embryos and stems of 30-day-old seedlings respectively. The relationship between cell growth, differentiation and the terpene lactone accumulation in these suspension cultures were investigated. HPLC determination indicated that, the ginkgolide B was found in the embryo derived cell suspension cultures at 0.044% of cell dry weight, and this result was the first time reported in this study. The accumulation of terpene lactone in the suspension cultures derived from both the embryo and seedling stems are effected by the level of the cell differentiation. The ginkgolide B was only found in small cell aggregates in the size smaller than 2mm, and the highest level of ginkgolide B was accumulated in cell aggregates in the size smaller than 1mm; however, the cell aggregates in the size bigger than 3mm could only produced bilobalide and ginkgolide A. In the same size aggregates of the suspension cultures the terpene lactone accumulation is strongly effected by the source of the explant. When the size of cell aggregates was in less than 1mm, the concentration of bilobalide, ginkgolide A and B in the cell suspension cultures derived from the embryos was 2, 1.4 and 0.56-fold, respectively, higher than that of cell cultures derived from seedling stems.

Bilobalides↗
PubMed1989

[Studies on synthetic new drug SC1001-sodium against epilepsy induced by coriaria lactone in rabbits].

In the present experiment, SC1001Na synthesized by West China University of Medical Sciences was used for studying to resist epilepsy induced by coriaria lactone. Forty-two normal male rabbits weighing 1.7-2.5 kg were randomly divided into four groups. The animals of the control group received coriaria lactone (3 mg/kg, i.m.). The animals in each of the experimental groups were injected separately with SC1001Na (100, 200 and 300 mg/kg, i.p.), but the control animals were not injected with SC1001Na. Thirty minutes later, the animals of the experimental groups were injected with the same dose of coriaria lactone as the control animals. The behavior of all animals before and after injection were observed continuously in 4-5 hours. The ECoG of eight animals of them were observed at the same time with telemetric method. The results of experiments indicated that SC1001Na is effective on epilepsy induced by coriaria lactone, in decreasing seizure rate, lengthening latent period, reducing seizure degree, as well as in decreasing mortality.

Animals↗
PubMed1983

Gas chromatographic determination of glucono-delta-lactone in foods.

A method is described for the gas chromatographic (GC) determination of glucono-delta-lactone in foods. A sample was homogenized with 60-70 degrees C water and filtered. The filtrate was buffered with NH4OH-NH4Cl pH 10 solution, and was passed through a QAE-Sephadex A25 column. The column was washed with water and glucono-delta-lactone was eluted with 0.1N HCl. An aliquot of the eluate was evaporated to dryness and derivatized with pyridine, N,O-bis(trimethylsilyl)trifluoroacetamide, and trimethylchlorosilane at room temperature. GC separation of glucono-delta-lactone as the TMS derivative was performed on a 2% OV-17 column at 180 degrees C. Recoveries from bread, jelly, soybean curd, and other foods fortified with 0.1% glucono-delta-lactone ranged from 92 to 106%, with standard deviations from 2.2 to 9.8%. The detection limit was approximately 0.025%.

Chromatography, Gas↗
PubMedDate not supplied

Sesquiterpene lactones (SL) part XXIV. Further studies on cytotoxic activities of SL in tissue culture of human cancer cells.

Cytotoxicity of most of the 18 new sesquiterpene lactones (SL), derivatives of germacran, guaian, pseudoguaian, and selinan, and related glycosides was studied by tissue culture method on human KB and HeLa cell lines. Eleven compounds with ED50, activity values between 0.24 and 2.40 microgram/ml (9,2.10(-7)--9.1.10(-6) M) were qualified for further in vivo investigation. It seems that: a) unsaturated alpha-exo-methylene-gamma-lactone ring:-O-CO-C=CH2 conjugated with basic terpene carbocyclic skeleton plays the main role for cytotoxicity of SL. The next determinants of the activity are apparently: b) sesquiterpenoid carbocyclic grouping (germacranolides (GE), pseudoguaianolides (PGU), guaianolides (GU), c) the position of cyclization of gamma-lactone ring (C6--C12) or C8--C12), d) some substituents with an epoxide and/or keto-function in different positions of sesquiterpenoids. The natural and modified alpha-exo-methylene-guaianolide-C3-glycosides (GUG) are not significantly more potent than the remaining alpha-exo-methylene-gamma-lactones.

Antineoplastic Agents↗
PubMedDate not supplied

Urinary and biliary disposition of the lactone and carboxylate forms of 20(S)-camptothecin in rats.

Recently, analytical methods have become available for determination of both the lactone (active form) and the carboxylate (inactive form) forms of 20(S)-camptothecin in biological fluids. Studies in our laboratory have shown that there are significant differences in the in vivo behavior of the two forms of camptothecin and that much higher plasma levels of the lactone form are present in rats after dosing with camptothecin (lactone) than after dosing with the sodium salt of the ring-opened camptothecin (carboxylate form). The present studies show that there are significant differences in the urinary and biliary elimination of the two forms and that the urinary excretion of the carboxylate form appears to be pH dependent. This apparent pH dependence of the urinary elimination of the carboxylate form may provide a method of reducing the bladder toxicity associated with the use of camptothecin. After administration of a 1 mg/kg iv dose of camptothecin (lactone) to rats, 10.1 +/- 4.2% of the dose was excreted into the urine and 7.5 +/- 4.2% of the dose was excreted into the bile. Following an equivalent intravenous dose of the carboxylate form, 39.5 +/- 10.4% of the dose was excreted into the urine and 26.4 +/- 8.9% of the dose was excreted into the bile.

Animals↗
PubMed1993

[Ganglioside lactones in human stomach and breast tumors].

Ganglioside lactones absent in homologous normal tissues have been found in minute amounts in human gastric and mammary tumours. In mammary gland tumours only the ganglioside GM3 lactone has been identified. Gastric tumours also contain the GM3 lactone; in one case a ganglioside GD3 lactone was identified.

Breast Neoplasms↗
PubMed1998

Topotecan lactone selectively binds to double- and single-stranded DNA in the absence of topoisomerase I.

We report the first experimental observation that a clinically important camptothecin [CPT; topotecan (TPT), a water-soluble CPT] binds directly and noncovalently to double-stranded DNA and single-stranded DNA structures in the absence of topoisomerase I, but only in the lactone form. We observed clear DNA sequence specificity of the TPT lactone binding to duplex DNA, which was comprised of alternating purine-pyrimidine sequences that contained dT. These structural studies of direct TPT lactone-DNA binding support several important considerations involving possible mechanism(s) of anticancer activity of CPT-type drugs containing a 20(S) lactone moiety.

Antineoplastic Agents↗
PubMed1999

Structural elucidation studies of polyketide tetrasubstituted delta-lactones by gas chromatography/tandem mass spectrometry and electrospray mass spectrometry

A series of tetrasubstituted polyketide delta-lactones were used to evaluate whether gas chromatography/tandem mass spectrometry (GC/MS/MS) and electrospray mass spectrometry (ESI-MS) are useful techniques for probing the structure and stereochemistry of such highly functionalised molecules. Analyses were performed with two commercially available mass spectrometers: a Finnigan/MAT GCQ instrument (CI source) and a Q-TOF Hybrid quadrupole time-of-flight instrument (ESI source). The analyses revealed that a range of variation in the structure and stereochemistry of the lactones did not affect the fragmentation pathway common to these molecules. By accurate mass determination (ESI-MS), the first two fragmentations were assigned to losses of water. Although it was anticipated that the initial dehydration would include the hydroxyl group at the 3-position of the lactones, evidence from deuterium- and (18)O-labelling studies suggests that the losses of water instead involve the oxygen atoms in the ester bond. Attempts to identify further the structures of daughter ions by GC/MS/MS were complicated by extensive rearrangements and non-specific hydrogen/deuterium migrations within the lactones. Together, these results illustrate the limitations of mass spectrometry in the structural elucidation of complex molecules. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2003

Multisite catalysis: a mechanistic study of beta-lactone synthesis from epoxides and CO--insights into a difficult case of homogeneous catalysis.

Carbonylation of epoxides with a combination of Lewis acids and cobalt carbonyls was studied by both theoretical and experimental methods. Only multisite catalysis opens a low-energy pathway for trans opening of oxirane rings. This ring-opening reaction is not easily achieved with a single-site metal catalyst due to structural and thermodynamic constraints. The overall reaction pathway includes epoxide ring opening, which requires both a Lewis acid and a tetracarbonylcobaltate nucleophile, yielding a cobalt alkyl-alkoxy-Lewis acid moiety. After CO insertion into the Co-C(alkyl) bond, lactone formation results from a nucleophilic attack of the alkoxy Lewis acid entity on the acylium carbon atom. A theoretical study indicates a marked influence of the Lewis acid on both ring-opening and lactone-formation steps, but not on carbonylation. Strong Lewis acids induce fast ring opening, but slow lactone formation, and visa versa: a good balance of Lewis acidity would give the fastest catalytic cycle as all steps have low barriers. Experimentally, carbonylation of propylene oxide to beta-butyrolactone was monitored by online ATR-IR techniques with a mixture of tetracarbonylcobaltate and Lewis acids, namely BF(3), Me(3)Al, Et(2)Al(+).diglyme, and a combination of Me(3)Al/dicobaltoctacarbonyl. We found that the last two mixtures are extremely active in lactone formation.

Journal Article↗
PubMed2004

Microbore HPLC method with online microdialysis for measurement of topotecan lactone and carboxylate in murine CSF.

We developed a chromatography method to measure lactone and carboxylate forms of topotecan (TPT) in mouse cerebrospinal fluid (CSF) using microdialysis sampling. The chromatography method utilized a microbore (0.8 mm) column. Analytes, which eluted in less than 5 min, were detected with a fluorescence detector. The calibration range was 0.25-100.0 ng/mL for both forms. The within-day and between-day precision was < or =16% for 0.8 ng/mL and < or =8.0% for 3, 12, and 80 ng/mL. Accuracy was +/-15% (0.8 and 3 ng/mL) and +/-10% (12 and 80 ng/mL). TPT lactone hydrolyzes to the carboxylate during sampling, so we developed an equation and parameters to describe the TPT lactone hydrolysis in artificial CSF (aCSF). After TPT administration, CSF dialysate samples (2 microL) were analyzed for lactone and carboxylate using online injection. The hydrolysis of each dialysate sample was then estimated and a correction applied. We conclude that this HPLC method coupled with online microdialysis sampling allows for the rapid measurement of both TPT forms in small volumes of murine CSF dialysate. The system allows for the determination of TPT pharmacokinetics in murine CSF and provides a tool to extend pharmacological studies in this brain compartment.

Animals↗
PubMed1997

Haloenol lactone: a new synergist of chemotherapy in vitro.

Over-expression of glutathione S-transferases (GST) has been found to play a significant role in multiple drug resistance in cancer chemotherapy. To combat GST-mediated drug resistance, GST inhibitors are being studied as potential synergists for effective cancer chemotherapy. We have designed and synthesized a haloenol lactone derivative as a mechanism-based inactivator of GST-pi isozyme. In the current study, we examined the inhibitory effect of the haloenol lactone compound on GST of a human renal carcinoma cell line UOK130 and found that this compound shows time-dependent GST inhibition in these cancer cells. The enzyme activity lost upon incubation with the haloenol lactone could not be restored by extensive dialysis against buffer. Pretreatment of the cancer cells with 1.0 microM of haloenol lactone increased cytotoxicity induced by cisplatin in the UOK130 cell line. This report further supports the possibility of synergizing alkylating agents in cancer chemotherapy by use of selective GST inhibitors.

4-Butyrolactone↗
PubMed1984

p-Chloromercuribenzoate specifically modifies thiols associated with the active sites of beta-ketoadipate enol-lactone hydrolase and succinyl CoA: beta-ketoadipate CoA transferase.

beta-Ketoadipate enol-lactone hydrolase (EC 3.1.1.24) and succinyl CoA: beta-ketoadipate transferase (EC 2.8.3.6) catalyze consecutive metabolic reactions in bacteria. The enzymes appear to be members of different families of related proteins. Enzymes within the enol-lactone hydrolase family appear to have diverged so extensively that common ancestry sometimes is not directly evident from comparison of NH2-terminal amino acid sequences of the proteins. Amino acid sequences at or near the active sites of the enzymes are likely to have been conserved, and hence a chemical proble that reacted specifically near the active sites of the enzymes might identify regions of amino acid sequence in which evolutionary affinities among widely divergent proteins could be identified. p-Chloromercuribenzoate appears to be such a probe because enol-lactone hydrolases and CoA transferases from Acinetobacter calcoaceticus and Pseudomonas putida were completely inhibited by stoichiometric quantities of the compound which appears to modify selectively cysteinyl side chains at or near the active sites of the enzymes. Stoichiometric inhibition of P. putida enol-lactone hydrolase was observed in the presence of excess dithiothreitol; therefore the reactive cysteinyl residue in this enzyme appears to be nucleophilic. The hydrolase is inhibited by beta-ketoadipate, but the compound must be supplied at 10 mM concentrations in order to achieve 50% inhibition, so the product inhibition is unlikely to be significant under physiological conditions.

Acinetobacter↗