Publications by authors named "Elisabeth Seguin"

One new indole alkaloid derivative, 5,6-dioxo-11-hydroxy voacangine () together with four known compounds (-), were isolated from the fruits of Stapf (Apocynaceae). Their structures were determined using 1D and 2D NMR, HRESI-MS, and a comparison with the literature. The new compound was found to be cytotoxic on human breast cancer MDA-MB 231 cells with IC values of 3.

View Article and Find Full Text PDF

Quinas contains several compounds, such as quinoline alkaloids, principally quinine, quinidine, cinchonine and cichonidine. Identified from barks of Cinchona, quinine is still commonly used to treat human malaria. Microwave-Integrated Extraction and Leaching (MIEL) is proposed for the extraction of quinoline alkaloids from bark of Cinchona succirubra.

View Article and Find Full Text PDF

The essential oil of aerial parts of Cachrys libanotis L. (Apiaceae) from east Algeria was extracted by hydrodistillation and analyzed by GC-FID and GC-MS. Thirty-one compounds were identified, the main components being germacrene-D (18.

View Article and Find Full Text PDF

Objective: To evaluate the antimicrobial activity of the methanol extract from the stem bark of Drypetes tessmanniana, fractions (DTB1-5) as well as compounds [friedelin (2), 3,7-dioxofriedelane (3), 3,15-dioxofriedelane (4), 3beta- O-(E)-3,5-dihydroxycinnamoyl-11-oxo-olean-12-ene (6), and 3beta,6alpha-dihydroxylup-20(29)-ene (7).

Methods: Agar disc diffusion was used to determine the sensitivity of the above samples, whilst the microdilution method was used for the determination of the minimal inhibitory concentration (MIC) and the minimal microbicidal concentrations (MMC).

Results: The diffusion test showed that the crude extract was able to prevent the growth of all tested organisms.

View Article and Find Full Text PDF

Two new dimethylpyrano-isoflavones, named erymildbraedin A (4) and B (5), were isolated from the stem bark of the Cameroonian medicinal plant Erythrina mildbraedii, along with four known ones, the linear congeners, scandenone (1), erysenegalinsein M (2), 5,4'-dihydroxy-2'-methoxy-8-(3,3-dimethylallyl)-2'',2''-dimethylpyrano[5,6:6,7]isoflavone (3), and the angular isoflavone eryvarin B (6), and two other compounds, fraxidin and scoparone. Their structures were elucidated by the usual spectroscopic methods and isoflavone effects on the growth of human breast, prostate, and endometrial adenocarcinoma cells were determined. Isoflavones 1, 3, and 6 strongly inhibited the growth of all three cell lines, supporting the notion that a non-oxidized isoprenyl group at C-8 is requisite for cytotoxic activity.

View Article and Find Full Text PDF

Two new friedelane-type triterpenes named 12alpha-hydroxyfriedelane-3,15-dione and 3beta-hydroxyfriedelan-25-al, together with six known compounds were isolated from the stems of Drypetes paxii Hutch. (Euphorbiaceae). Their structures were established on the basis of conventional 1 dimensional (1D) NMR methods, 2D shift-correlated NMR experiments and mass spectra.

View Article and Find Full Text PDF

The air-dried stems and ripe fruit of Drypetes inaequalis Hutch. (Euphorbiaceae) were studied. Four triterpene derivatives, characterized as lup-20(29)-en-3beta,6alpha-diol, 3beta-acetoxylup-20(29)-en-6alpha-ol, 3beta-caffeoyloxylup-20(29)-en-6alpha-ol and 28-betad-glucopyranosyl-30-methyl 3beta-hydroxyolean-12-en-28,30-dioate along with 10 known compounds were isolated from the whole stems.

View Article and Find Full Text PDF

The MeOH extract of the stem barks of Drypetes tessmanniana (Euphorbiaceae) afforded two new triterpene derivatives characterized as 3beta-O-(E)-3,5-dihydroxycinnamoyl-11-oxo-olean-12-ene and 3beta,6alpha-dihydroxylup-20(29)-ene together with seven known compounds. Their structures were established on the basis of spectral analysis.

View Article and Find Full Text PDF

Sarcodifurines A and B are two original dihydrofuroquinolines isolated from Sarcomelicope follicularis, a New Caledonian tree. The cytotoxicity and antiproliferative activity of these two alkaloids were investigated against 8 distinct cell lines representative of the most frequent solid tumors developing in human. Cytotoxicity of sarcodifurines was low on the 8 cell lines, with, for example, less than 10% of the total cells killed after 24 h exposure at 10 microM and IC(50) approximately 7.

View Article and Find Full Text PDF

The essential oils of the aerial parts of Kundmannia sicula (L.) DC collected from two Algerian localities, El Kala (near the coast) and Béjaia (from a meadow about 10 km from the coast), were analysed by GC and GC-MS. Although both samples showed similar overall chemical compositions, the major components of the Béjaia sample were identified as being spathulenol (14.

View Article and Find Full Text PDF

This study investigated, in mice, the antidepressant like effect of hyperfoliatin, a prenylated phloroglucinol derivative isolated from the aerial parts of Hypericum perfoliatum, as well as its action on monoaminergic systems. In the forced-swimming test, hyperfoliatin dose-dependently reduced immobility time. Immobility was interpreted as an expression of "behavioural despair", which could be a component of depression syndrome.

View Article and Find Full Text PDF

An actinomycete strain NM94 was isolated from a Saharan soil sample by a dilution agar plating method using chitin-vitamins B medium supplemented with penicillin. The strain presented the morphological and chemical characteristics of the genus Nonomuraea. On the basis of 16S rDNA analysis and physiological tests, this isolate was found to be quite different from the known species of Nonomuraea and might be new.

View Article and Find Full Text PDF

Condensation of 1-bromo-2-naphthalenecarboxylic acid (9) with 7-methoxy-2,2-dimethyl-2H-1-benzopyran-5-ylamine (13) followed by acid-mediated cyclization afforded 6-methoxy-3,3-dimethyl-3,14-dihydro-7H-benzo[c]pyrano[3,2-h]acridin-7-one (15), which was further methylated into 6-methoxy-3,3,14-trimethyl-3,14-dihydro-7H-benzo[c]pyrano[3,2-h]acridin-7-one (benzo[c]acronycine) (3) and 6,7-dimethoxy-3,3-dimethyl-3H-benzo[c]pyrano[3,2-h]acridine (4). Osmium tetroxide oxidation of 15 gave the (+/-)-cis-diol 16, which afforded the benzopyranoacridine and benzopyranoacridone esters 17-22 upon acylation. Condensation of 9 with suitable aminoquinolines 23-25 afforded the carboxylic naphthylquinolylamines 26-28.

View Article and Find Full Text PDF

Hyperfoliatin, a new polyisoprenylated phloroglucinol derivative was isolated from the aerial parts of Hypericum perfoliatum (Clusiaceae) collected in Algeria. The structure of hyperfoliatin was elucidated on the basis of its spectral data, mainly MS and multiple-pulse NMR.

View Article and Find Full Text PDF

Chemical studies of the EtOAc extract of Gambeya boukokoensis Aubr. et Pellegr. stem bark led to the isolation of eight compounds.

View Article and Find Full Text PDF

The cytotoxic and antitumor activities of cis-1,2-diacyloxy-6-methoxy-3,3,14-trimethyl-1,2,3,14-tetrahydro-7H-benzo[b]pyrano[3,2-h]acridin-7-one derivatives 3, 6-9 were strongly correlated with their ability to give covalent adducts with purified, as well as genomic, DNA. Such adducts involve reaction between the exocyclic N-2 amino group of guanines exposed in the minor groove of double helical DNA and the leaving ester group at the benzylic position 1 of the drug. A transesterification process of the ester group from position 2 to position 1 in aqueous medium accounted for the intense activity of the cis-1-hydroxy-2-acyloxy-6-methoxy-3,3,14-trimethyl-1,2,3,14-tetrahydro-7H-benzo[b]pyrano[3,2-h]acridin-7-one derivatives 10-13.

View Article and Find Full Text PDF

The methanol extract of the dried stem bark of Drypetes armoracia Pax & Hoffm. afforded two compounds named drypearmoracein A, (E)-4,5,6,7-tetrahydroxy-2-benzylhept-2-enoic acid and drypearmoracein B, 2,3-dihydroxy-9,10-tetrahydroanthra-1,4-quinone along with five known compounds: friedelan-3 beta-ol, friedelin, friedelane-3,7-dione, drypemolundein B and beta-stigmasterol. Their structures were established on the basis of spectroscopic analysis and chemical evidence.

View Article and Find Full Text PDF

The novel 6-dialkylaminoalkylamino-3,3,12-trimethyl-3,12-dihydro-7H-pyrano[2,3-c]acridine-7-ones 5-11 and their benzo [b]pyrano[2,3-h]acridine-7-one counterparts 12-18 were prepared by treatment of acronycine (1) or benzo[b]acronycine (4) with an excess of the appropriate dialkylaminoalkylamine. In both series, the introduction of a dialkylaminoalkylamino side chain at position 6 resulted in a significant increase of the cytotoxic activity against L1210 cells when compared with the parent compounds bearing a methoxy group, accompanied with an increased potency to arrest cells in the G2 + M phases of the cell cycle.

View Article and Find Full Text PDF

Three new natural dithiopyrrolone antibiotics, 3-methyl-2-butenoylpyrrothine (1), tigloylpyrrothine (2), and n-butyropyrrothine (3) were isolated along with the known isobutyropyrrothine (4) and thiolutin (5) from the fermentation broth of Saccharothrix sp. SA 233. The structures of the novel compounds were established on the basis on their spectral data.

View Article and Find Full Text PDF

Three new natural antibacterial and antifungal dithiolopyrrolone antibiotics were isolated along with the known iso-butyropyrrothine and thiolutine from the fermentation broth of an actinomycete strain which was isolated from a saharian palm grove soil collected at Adrar, south Algeria. The strain was identified as Saccharothrix sp. The three new antibiotics exhibited broad antimicrobial activity against gram-positive bacteria, yeasts and fungi in vitro.

View Article and Find Full Text PDF

Acronycine is active against a broad spectrum of solid tumors. Structure activity relationships demonstrated the crucial role of the 1,2-double bond. A hypothesis of bioactivation into 1,2-epoxide led to the development of a series of 1,2-dihydroxy-1,2-dihydroacronycine and 1,2-dihydroxy-1,2-dihydrobenzo[b]acronycine diesters that exhibited an increased potency when compared with the parent compound.

View Article and Find Full Text PDF

Five new hexaoxygenated chalcones and one new chalcone photodimer were synthesized and their cytotoxicity against leukemia cell line L-1210 was studied. The three more active compounds were tested for their activity on the inhibition and promotion of tubulin assembly and it was found that these chalcones do not interfere with the tubulin-microtubule system at cytotoxic concentrations, and therefore operate by some different mechanism of action.

View Article and Find Full Text PDF

A new iridoid glucoside dimer, coelobillardin (1), was isolated from the aerial parts of Coelospermum billardieri. Its structure has been elucidated on the basis of MS and NMR data. From a biogenetic point of view, this compound, which includes a cyclobutane basic core, should be considered as a [2+2] dimerization product of (E)-10-(4-hydroxycinnamoyloxy)loganin, which is the major iridoid isolated from the plant.

View Article and Find Full Text PDF