[Action of an extract of Vanda coerulea on the senescence of skin fibroblasts]. / Action d'un extrait de Vanda coerulea sur la sénescence de fibroblastes cutanés.

The family of the orchids to date is poorly studied as a potential source of molecules with biological activity. The phytochemical analysis of extracts of Vanda coerulea stems (Orchidaceae), the isolation and the purification of the secondary metabolites realized by CLHP followed with high-resolution mass spectrometry and mono and two-dimensional nuclear magnetic resonance made it possible to identify the joint presence in an orchid of three stilbenoïds i.e, imbricatin, methoxycoelonin and gigantol. By flow cytometry, it is shown that the replicative senescence of human normal skin fibroblasts involves a reduction in the number of cells in phase S. A proteins chips technology dedicated to cell cycle proteins makes it possible to correlate this decrease of the number of cells in phase S to a decrease in cyclin E and cyclin dependant kinase 2, cdk2. The treatment by an ethanolic extract of stems of Vanda coerulea titrated in the three stilbenoids restores the percentage at an equivalent rate to that of young cells and the rate of cyclin E and, cdk2, thus bringing a beginning of explanation of their mechanism. These activities let predict an interesting potential as active ingredients to fight against the visible signs of cutaneous ageing.

Modulation by polyamines of apoptotic pathways triggered by procyanidins in human metastatic SW620 cells.

We showed previously that inhibition of polyamine catabolism with the polyamine oxidase inhibitor MDL 72527 (MDL) potentiates the apoptotic effects of apple procyanidins (Pcy) in SW620 cells. Here we report that Pcy caused an activation of the intrinsic apoptotic pathway through enhanced polyamine catabolism and mitochondrial membrane depolarization. MDL in the presence of Pcy caused a profound intracellular depletion of polyamines and exerted a protective effect on mitochondrial functions. MDL potentiation of Pcy-triggered apoptosis was reversed by addition of exogenous polyamines. In addition, MDL in combination with Pcy activated the extrinsic apoptotic pathway through enhanced TRAIL-death receptor (DR4/DR5) expression. Potentiation of Pcy-triggered apoptosis by MDL was inhibited when cells were exposed to specific inhibitors of DR4/DR5. These data indicate that the depletion of intracellular polyamines by MDL in the presence of Pcy caused a switch from intrinsic to extrinsic apoptotic pathways in human colon cancer-derived metastatic cells.

[Complementary and alternative medicines taken by cancer patients]. / Médecines complémentaires et alternatives suivies par les patients cancéreux en France.

244 cancer patients from 2 public hospitals (one adult, one pediatric) and one private clinic receiving chemotherapy were asked about complementary and alternative medicine (CAM). Nearly 28% used one or several CAM, especially homeopathy (60%), special diets or dietary supplements (44%), mistletoe (40%) and less frequently acupuncture or other treatments. These CAM are started 4 to 5 months after the onset of chemotherapy. The reasons for using CAM are enhance host defenses, better tolerance of treatment, but also for nearly 27% to treat cancer. All patients were treated by anticancer classical treatments and none thought to stop them. CAM are prescribed especially by homeopathic doctors. 30% of patients using CAM did not inform their oncologist of their CAM treatment. The same conclusions were drawn for the only 10 pediatric patients. The majority of all patients did not take any CAM before their cancer. In a multivariate analysis, female, young age (30-50 y) are correlated to CAM. All patients taking CAM are satisfied by the CAM treatment with good subjective results on their general status, fatigue and nausea-vomiting. These results are similar to other studies done in Europe.

Anti-proliferative effect of Euphorbia stenoclada in human airway smooth muscle cells in culture.

The ethanolic extract of a Malagasy species Euphorbia stenoclada (ES) (Euphorbiaceae), traditionally used as a herbal remedy against asthma and acute bronchitis, was tested to evaluate possible anti-proliferative activity on human airway smooth muscle cells (HASMC). The ES ethanolic extract totally abolished the interleukin-1beta (IL-1beta) induced proliferation of HASMC (IC(50)=0.73+/-0.08 microg/mL). No cytotoxic effect was observed up to 20 microg/mL. A bioassay-guided fractionation of the ethanolic extract was performed by reversed-phase (RP) flash chromatography, giving five fractions (FA to FE) where fraction FE was the only active one (IC(50)=0.38+/-0.02 microg/mL). The purification of this bioactive fraction FE was carried out by RP-HPLC affording six sub-fractions 1-6, and only sub-fraction 5 kept the anti-proliferative activity. Its major constituent was identified as quercetin (IC(50)=0.49+/-0.12 microg/mL) by means of HPLC/UV/MS and co-elution with the authentic standard. Quercitrin was also identified in the fraction FE but was inactive. A structure-activity relationship with flavonols determined that methylation reduced the anti-proliferative activity whereas glycosylation abolished it. The present study shows that the anti-proliferative properties of Euphorbia stenoclada are mediated through the presence of quercetin that may explain the traditional use of this plant as a remedy against asthma.

Quantitative determination of naphthoquinones of Impatiens species.

A convenient and reliable reversed phase-HPLC method has been developed and validated for the quantitative determination of naphthoquinones present in the aerial parts of Impatiens glandulifera (Balsaminaceae) during two growing seasons (May to August 1998 and June to October 1999). Maximal content (0.8-1.1%) of 2-hydroxy-1,4-naphthoquinone and its 2-methylated derivative was observed in flowers collected between July and August. The procedure was applied to compare the pigment content in three other species of Impatiens but showed 2.5-37 times lower levels than those found in I. glandulifera.

Antiprotozoal activities of Colombian plants.

In our search for therapeutical alternatives for antiprotozoal chemotherapy, we collected a selection of 44 plants from western Colombia upon ethnopharmacological and chemotaxonomic considerations. Polar and apolar extracts of these species were examined for antimalarial activity using in vitro tests with two clones of Plasmodium falciparum. Leishmanicidal and trypanocidal activity were determined in vitro using promastigote and amastigote forms of several strains of Leishmania sp. and epimastigotes of Trypanosoma cruzi. Among the selected plants, the 15 following species showed good or very good antiprotozoal activity in vitro: Aspidosperma megalocarpon, Campnosperma panamense, Conobea scoparioides, Guarea polymera, Guarea guidonia, Guatteria amplifolia, Huberodendron patinoi, Hygrophila guianensis, Jacaranda caucana, Marila laxiflora, Otoba novogranatensis, Otoba parviflora, Protium amplium, Swinglea glutinosa and Tabernaemontana obliqua. Cytotoxicity was assessed in U-937 cells and the ratio of cytotoxicity to antiprotozoal activity was determined for the active extracts. Ten extracts from eight species showed selectivity indexes > or = 10. Among the extracts that showed leishmanicidal activity, the methylene chloride extract of leaves from C. scoparioides showed a selectivity index in the same range that the one of the Glucantime control. Several of the active leishmanicidal plants are traditionally used against leishmaniasis by the population of the concerned area.

Bioactive acridone alkaloids from Swinglea glutinosa.

A new prenylated acridone alkaloid, 1,3,5-trihydroxy-2,8-bis(3-methylbut-2-enyl)-10-methyl-9-acridone (1), was isolated from the stembark of Swinglea glutinosa, along with three known acridone alkaloids, 5-hydroxynoracronycine (2), 1,3,5-trihydroxy-4-methoxy-2-(3-methylbut-2-enyl)-10-methyl-9-acridone (3), and 1,3,5-trihydroxy-4-methoxy-10-methylacridone (4). The isolated alkaloids were assessed in vitro against chloroquine-sensitive and -resistant Plasmodium falciparum strains and for cytotoxicity using HeLa cells.

Saponins from Strasburgeria robusta.

The isolation of three saponins, 24-hydroxytormentic acid ester glucoside (1), niga-ichigoside F1 (2) and niga-ichigoside F2 (3), from the stem bark of Strasburgeria robusta, an endemic plant from New Caledonia, is reported.

Improved procedure for the quality control of Hypericum perforatum L.

A new, fast and reliable procedure for the quantification of the major compounds of Hypericum perforatum L. has been developed. Four naphthodianthrones (protopseudohypericin, pseudohypericin, protohypericin, hypericin) and two phloroglucinols (hyperforin, adhyperforin) were assayed by HPLC using a short (17 min) linear gradient, with hypericin and hyperforin as external standards. Extraction of dried plant material with methanol in the dark at room temperature for 2 h led to a complete recovery of phloroglucinols but only a partial recovery of the naphthodianthrone derivatives. Treatment of plant material with water:ethanol (40:60, v/v) in a water bath shaker at 80 degrees C led to the total extraction of hypericins, but a 10% loss of total hyperforins was also observed. The two extraction methods, applied successively to the same sample, allowed the complete extraction of all compounds of interest. A 5 min exposure of the crude extract of H. perforatum to sunlight (1 E/m2) induced a 96% loss of hyperforins, whereas the dry plant material lost only 20% of hyperforins after 2 h exposure to sunlight (24 E/m2).

Triterpenoid saponins from Isertia pittieri.

Two new 27-nor-triterpenoid saponins, pyrocincholic acid 3 beta-O-beta-D-quinovopyranosyl-28-[beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl] ester (1) and pyrocincholic acid 3 beta-O-beta-D-quinovopyranosyl(1-->6)-beta-D-glucopyranosyl-28-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl] ester (2) were isolated from the stem bark of Isertia pittieri, together with two known bidesmosidic quinovic acid glycosides. The structures of 1 and 2 were determined on the basis of spectroscopic studies.

Suppression of azoxymethane-induced preneoplastic lesions and inhibition of cyclooxygenase-2 activity in the colonic mucosa of rats drinking a crude green tea extract.

We determined the effects of a crude green tea extract given as drinking fluid on the promotion/progression phase of colon carcinogenesis in rats after induction of the neoplastic process by azoxymethane. Adult Wistar rats were given azoxymethane (15 mg/kg i.p.) once a week for two weeks. One week after the second injection, the rats were randomly divided into two groups. One group (n = 8) received daily prepared aqueous solutions of green tea extracts (GTE; 0.02%, wt/vol); the control group (n = 8) received tap water. After six weeks, rats receiving GTE showed a 60% reduction in the number of colonic preneoplastic lesions (aberrant crypts). The number of individual crypts per aberrant crypt focus (crypt multiplicity) was significantly reduced in the GTE group; the majority (80%) of the remaining aberrant foci contained only one or two preneoplastic crypts. A significant and selective decrease of cyclooxygenase (COX)-2 activity was observed in the colon of rats receiving GTE (23 +/- 3 vs. 117 +/- 30 mU/mg protein in controls), whereas COX-1 showed no alterations. Our data demonstrate that GTE reduces COX-2 and suppresses the formation of colonic preneoplastic lesions. They provide new insights into the mechanism of chemopreventive and anti-inflammatory properties of green tea.

Interactions of the monomeric and dimeric flavones apigenin and amentoflavone with the plasma membrane of L929 cells; a fluorescence study.

Flavonoids are ubiquitous polyphenolic compounds, found in vascular plants, which are endowed with a large variety of biological effects. Some of these effects have been assumed to result from interactions with the cell plasma membrane. In order to investigate the nature of these interactions a fluorescence study was performed with two flavonoids, currently used in one of the laboratories: apigenin and its homologous dimer amentoflavone. After preliminary assays with DPH in several types of phospholipid liposomes, the effects of these flavonoids on the membrane of mouse L929 fibroblasts were compared, using the non-permeant probe TMA-DPH. Amentoflavone, unlike apigenin, induced a static quenching effect, which denoted an important, but reversible, association of the molecule with the plasma membrane. In addition, amentoflavone treatment induced a dose-dependent increase in TMA-DPH fluorescence anisotropy, which could be interpreted as an increase in membrane lipidic order. For apigenin, the effect was much less important. Moreover, exploiting the capacity of TMA-DPH to label endocytic compartments, it was shown that, after association with the membrane, amentoflavone is not internalized into the cell. Possible correlations of these membrane effects with other biological properties are discussed.

Natural dietary polyphenolic compounds cause endothelium-dependent vasorelaxation in rat thoracic aorta.

This study investigated the possible active principles which support the endothelial nitric oxide-dependent relaxation produced by red wine and other plant polyphenolic compounds in thoracic aorta from male Wistar rats (12-14 wk old). Relaxation experiments were recorded isometrically on vessels precontracted with norepinephrine. Ten different chromatographic fractions (3-18 mg) isolated from red wine polyphenolic compounds (RWPC) and some available defined polyphenols (10-15 mg) were tested. Fractions enriched into either anthocyanins or oligomeric condensed tannins exhibited endothelium-dependent vasorelaxant activity (maximal relaxation in the range of 59-77%) comparable to the original RWPC. However, polymeric condensed tannins elicited a weaker vasorelaxant activity than the original RWPC (maximal relaxation ranged between 20-47%, P < 0.01). Moreover, the representative of either phenolic acid derivatives (benzoic acid, vanillic acid, gallic acid), hydroxycinnamic acid (p-coumaric acid, caffeic acid) or the flavanol [(+)-epicatechin] classes failed to induce this type of response. Among the anthocyanins, delphinidin (maximal relaxation being 89%), but not malvidin or cyanidin, showed endothelium-dependent vasorelaxation. These results show that anthocyanins and oligomeric-condensed tannins exhibited a pharmacological profile comparable to the original RWPC. These compounds may be involved in the reduction of cardiovascular mortality related to the presence of wine, fruits and vegetables in the diet.

Structure elucidation of three triterpene glycosides from the trunk of Argania spinosa.

The structures of three novel saponins from Argania spinosa, named arganines G, H, and J, have been elucidated by MS and NMR techniques as 3-O-beta-D-apiofuranosyl- (1-->4)-beta-D-glucopyranosyl-28-O-beta-D-glucopyranosylbayogenin (1), 3-O-beta-D-apiofuranosyl-(1-->4)-beta-D-glucopyranosyl-28-O-alpha- L- arabinopyranosylbayogenin (2), and 3-O-beta-D-apiofuranosyl-(1-->4)-beta-D-glucopyranosyl-28-O- [beta-D-apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L - rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]bayogenin (3), respectively.

Flavonoids extracted from fonio millet (Digitaria exilis) reveal potent antithyroid properties.

Digitaria exilis (fonio) is a tiny variety of millet commonly eaten by inhabitants of semiarid regions. A sample of fonio collected right in the middle of a severely iodine-depleted goitrous endemic was submitted to phytochemical investigations in order to assess the potential contributory roles played by vegetable molecules to the goitrogenic processes. The total content of flavonoids amounts to 500 mg/kg of the edible whole cereal grains. Their extraction and identification fail to detect the C-glycosylflavones described in other millet varieties but point out the presence of apigenin (A = 150 mg/kg) and of luteolin (L1 = 350 mg/kg). Ten percent of A and 80% of L1 are present in free form, whereas the remaining 90% of A and 20% of L1 are bound as O-glycosylflavones. Both A and L1 aglycones manifest strong anti-thyroid peroxidase (TPO) activities, resulting in a significant reduction of the hormonogenic capacity of this enzyme. In addition, L1 significantly depresses the cyclic AMP phosphodiesterase, implying a concomitant overproduction of the thyrotropin-dependent nucleotide. These last unreported data are regarded as counteracting to some extent the TPO-mediated goitrogenic properties of L1. Since fonio is devoid of other molecules likely to interfere with the thyroid function, our results are directly and casually attributed to A and L1 found in the customary diet.

Triterpenoid saponins from Mimosa pigra.

Two novel triterpene glycosides have been isolated from Mimosa pigra. The aglycone of these two compounds was identified as machaerinic acid by 1H- and 13C-nmr spectroscopy and by comparison with an authentic sample. This aglycone is substituted at position C-3 by an identical oligosaccharide chain in these glycosides, and at position C-21 by either a Z/E-methoxycinnamic [1] unit or an E-cinnamic acid [2] unit.

Comparative antilipoperoxidant, antinecrotic and scavenging properties of terpenes and biflavones from Ginkgo and some flavonoids.

Ginkgo biloba extract is known to be efficient in diseases associated with free radical generation. This study compares the in vitro effect of some constituents of Ginkgo against lipid peroxidation and cell necrosis of isolated rat hepatocytes, and against superoxide anion which is generally implicated in cell damages.

Cytotoxic activity of Amaryllidaceae alkaloids.

25 Amaryllidaceae alkaloids belonging to different skeletal types were evaluated for their cytotoxic activity against one murine non-tumoral cell line (LMTK) and two human tumoral cell lines (Molt4 and HepG2) according to established protocols. Significant differences of activity related with the type of skeleton of the tested alkaloids could be observed. Pretazettine (22) was among the most active compound among the 25 tested alkaloids on the Molt4 lymphoid cells, but was inactive against HepG2 hepatoma. On the other hand, lycorenine (11) was found to be the most cytotoxic compound against HepG2 hepatoma, even though it appears to be active against Molt4 cells. Almost all of the tested alkaloids showed cytotoxic activity against fibroblastic LMTK cells. Only mesembrenone (25) showed some specificity against Molt4 cells in comparison to LMTK cells.