title: Screening and fractionation of plant extracts with antiproliferative activity on human peripheral blood mononuclear cells.
abstract: Three hundred and thirteen extracts from 136 Brazilian plant species belonging to 36 families were tested for their suppressive activity on phytohemaglutinin (PHA) stimulated proliferation of human peripheral blood mononuclear cells (PBMC). The proliferation was evaluated by the amount of [3H]-thymidine incorporated by the cells. Twenty extracts inhibited or strongly reduced the proliferation in a dose-dependent manner at doses between 10 and 100 micro g/ml. Three of these extracts appeared to be non-toxic to lymphocytes, according to the trypan blue permeability assay and visual inspection using optical microscopy. Bioassay-guided fractionation of Alomia myriadenia extract showed that myriadenolide, a labdane diterpene known to occur in this species, could account for the observed activity of the crude extract. Using a similar protocol, an active fraction of the extract from Gaylussacia brasiliensis was obtained. Analysis of the 1H and 13C NMR spectra of this fraction indicates the presence of an acetylated triterpene whose characterization is underway. The extract of Himatanthus obovatus is currently under investigation.
authors.affiliation: Laboratório de Química de Produtos Naturais, Centro de Pesquisas Ren Rachou, Fiocruz, Belo Horizonte, MG, 30190 002, Brasil.
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Souza-Fagundes
authors.forename: Ana B R
authors.initials: AB
authors.lastname: Queiroz
authors.forename: Olindo Assis
authors.initials: OA
authors.lastname: Martins Filho
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gazzinelli
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Corrêa-Oliveira
authors.forename: Tânia M A
authors.initials: TM
authors.lastname: Alves
authors.forename: Carlos L
authors.initials: CL
authors.lastname: Zani
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D001681:Biological Assay; D001938:Brazil; D002455:Cell Division / Q000187:drug effects*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects*; D007959:Lymphocyte Culture Test, Mixed; D010835:Phytohemagglutinins / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology*; D013936:Thymidine / Q000494:pharmacology
chemical_list: D000276:Adjuvants, Immunologic; D010835:Phytohemagglutinins; D010936:Plant Extracts; D013936:Thymidine