A strategy to identify specific biomarkers related to the effects of a PCDD/F mixture on the immune system of marine mammals

in Talanta (2004), 63(5), 1225-1230

The cell lines chosen have demonstrated a positive response in terms of cell proliferation and associated modifications in proteins content, evaluated through DNA and proteins synthesis, at ... [more ▼]

The cell lines chosen have demonstrated a positive response in terms of cell proliferation and associated modifications in proteins content, evaluated through DNA and proteins synthesis, at environmentally relevant dose of dioxins, brought by a typical environmental PCDD/F mixture. The response is time and species dependent. After completion of the identification of proteins affected by the intoxication, we will identify a set of specific proteins whose expression is correlated to the dioxin dose and submit the cell culture to the treatment with a single chemical as well as with mixtures. We hope that this will allow us to construct and validate a set of protein biomarkers of exposure to pollutants that will show a predictive aspect for unknown chemicals. The quantitative analysis of the set of biomarkers can then be a more specific bioassay and an alternative to physico-chemical or other already established bioanalytical methods for screening purposes. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Identification of specific biomarkers related to the effects of pollutants on the immune system of marine mammals

Poster (2004)

Identification of specific biomarkers related to the effects of pollutants on the immune system of marine mammals

Poster (2003, December)

Intégration des méthodes biologiques et physico-chimiques pour l’étude du mode d’action de substances d’origine naturelle

Conference (2002, September)

Activités cytotoxiques et apoptotiques de gigantéosides D et E isolés de Cephalaria gigantea

Poster (2002, September)

Apoptosis of HL-60 leukemia cells induced by the bisindole alkaloids sungucine and isosungucine from Strychnos icaja

in Planta Medica (2002), 68(7), 591-595

Sungucine and isosungucine are two bisindole alkaloids isolated from the roots of the African plant Strychnos icaja Baillon. They both exhibit antiplasmodial activities but also show cytotoxic effects ... [more ▼]

Sungucine and isosungucine are two bisindole alkaloids isolated from the roots of the African plant Strychnos icaja Baillon. They both exhibit antiplasmodial activities but also show cytotoxic effects against human cancer cell lines. In order to elucidate their mechanism of action, we have investigated the interaction of the alkaloids with DNA and their capacity to inhibit nucleic acids and protein synthesis in the human HL-60 promyelocytic leukemia cell line. Cell treatment with both sungucine and isosungucine leads to the appearance of a hypo-diploid DNA content peak. Western blotting analysis reveals that the two alkaloids induce cleavage of the poly(ADP-ribose) polymerase (PARP) and promote the cleavage of a caspase-3 DEVD peptide substrate. The activation of the caspase cascade is accompanied with a fragmentation of DNA in cells, as revealed by the TUNEL assay. Altogether, the results shed light on the mechanism of action of these two plant alkaloids and identify signaling factors involved in (iso)sungucine-induced apoptosis in HL-60 cells. [less ▲]

Contribution to the study of Alchornea cordifolia (Schumach. & Thonn.)

Conference (2002, March)

Ent-Trachyloban-3beta-ol, a new cytotoxic diterpene frm Croton zambesicus

in Planta Medica (2002), 68

The dichloromethane extract of leaves of Croton Zambesicus (Euphorbiaceae) showing in vitro cytotoxicity against huma cervix carcinoma cells was investigated in order to identify its active compounds. A ... [more ▼]

The dichloromethane extract of leaves of Croton Zambesicus (Euphorbiaceae) showing in vitro cytotoxicity against huma cervix carcinoma cells was investigated in order to identify its active compounds. A bio-guided fractionation by HSCCC followed by MPLC led us to isolate a trachylobane diterpene, ent-trachyloban-3beta-ol, with cytotoxic properties (IC50 on HeLa cells = 7.3 ùg/ml). This is the first report on the cytotoxicity of a trachylobane diterpene. [less ▲]

Strychnogucines a and B, Two New Antiplasmodial Bisindole Alkaloids from Strychnos Icaja

in Journal of Natural Products (2001), 64(1), 12-16

A reinvestigation of Strychnos icaja roots has resulted in the isolation of two tertiary quasi-symmetric bisindole alkaloids named strychnogucines A (1) and B (2). Their structures were identified by ... [more ▼]

A reinvestigation of Strychnos icaja roots has resulted in the isolation of two tertiary quasi-symmetric bisindole alkaloids named strychnogucines A (1) and B (2). Their structures were identified by means of spectroscopic data interpretation. Compound 2 was highly active in vitro and compound 1 moderately active against four strains of Plasmodium falciparum. Strychnogucine B (2) was more active against a chloroquine-resistant strain than against a chloroquine-sensitive one (best CI(50), 80 nM against the W2 strain). In addition, this compound showed a selective antiplasmodial activity with 25-180 times greater toxicity toward P. falciparum, relative to cultured human cancer cells (KB) or human fibroblasts (WI38). [less ▲]

Evaluation of the antitrypanosomal activity of several plants traditionally used in Benin to treat sleeping sickness

Poster (2001)