title: Antioxidant and antiradical activities of Manihot esculenta Crantz (Euphorbiaceae) leaves and other selected tropical green vegetables investigated on lipoperoxidation and phorbol-12-myristate-13-acetate (PMA) activated monocytes.
abstract: Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae), Manihot esculenta Crantz (Euphorbiaceae) and Pteridium aquilinum (Dennstaedtiaceae) leaves are currently consumed as vegetables by migrants from sub-Saharan Africa living in Western Europe and by the people in the origin countries, where these plants are also used in the folk medicine. Manihot leaves are also eaten in Latin America and some Asian countries. This work investigated the capacity of aqueous extracts prepared from those vegetables to inhibit the peroxidation of a linoleic acid emulsion. Short chain, volatile C-compounds as markers of advanced lipid peroxidation were measured by gas chromatography by following the ethylene production. The generation of lipid hydroperoxides, was monitored by spectroscopy using N-N'-dimethyl-p-phenylene-diamine (DMPD). The formation of intermediate peroxyl, and other free radicals, at the initiation of the lipid peroxidation was investigated by electron spin resonance, using α-(4-pyridyl-1-oxide)-N-tert-butylnitrone as spin trap agent. The ability of the extracts to decrease the cellular production of reactive oxygen species (ROS) in "inflammation like" conditions was studied by fluorescence technique using 2',7'-dichlorofluorescine-diacetate as fluorogenic probe, in a cell model of human monocytes (HL-60 cells) activated with phorbol ester. Overall the extracts displayed efficient concentration-dependent inhibitory effects. Their total polyphenol and flavonoid content was determined by classic colorimetric methods. An HPLC-UV/DAD analysis has clearly identified the presence of some polyphenolic compounds, which explains at least partially the inhibitions observed in our models. The role of these plants in the folk medicine by sub-Saharan peoples as well as in the prevention of oxidative stress and ROS related diseases requires further consideration.
authors.affiliation: Laboratory of Pharmacognosy, Department of Pharmacy, Interfaculty Centre of Drug Research, Faculty of Medicine, University of Liège, Sart Tilman, Belgium. cntsumbu@doct.ulg.ac.be
authors.forename: Cesar N
authors.initials: CN
authors.lastname: Tsumbu
authors.forename: Ginette
authors.initials: G
authors.lastname: Deby-Dupont
authors.forename: Monique
authors.initials: M
authors.lastname: Tits
authors.forename: Luc
authors.initials: L
authors.lastname: Angenot
authors.forename: Thierry
authors.initials: T
authors.lastname: Franck
authors.forename: Didier
authors.initials: D
authors.lastname: Serteyn
authors.forename: Ange
authors.initials: A
authors.lastname: Mouithys-Mickalad
mesh_terms: D028483:Abelmoschus / Q000737:chemistry; D002849:Chromatography, Gas; D004578:Electron Spin Resonance Spectroscopy; D005419:Flavonoids / Q000032:analysis*; D005609:Free Radicals / Q000378:metabolism; D018922:HL-60 Cells / Q000378:metabolism; D031584:Hibiscus / Q000737:chemistry; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D002365:Manihot / Q000737:chemistry; D009000:Monocytes / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D059808:Polyphenols / Q000032:analysis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D032498:Pteridium / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism; D013057:Spectrum Analysis
chemical_list: D005419:Flavonoids; D005609:Free Radicals; C498702:PMAIP1 protein, human; D010936:Plant Extracts; D059808:Polyphenols; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species