title: Constituents of the roots and leaves of Ekebergia capensis and their potential antiplasmodial and cytotoxic activities.
abstract: A new triterpenoid, 3-oxo-12β-hydroxy-oleanan-28,13β-olide (1), and six known triterpenoids 2-7 were isolated from the root bark of Ekebergia capensis, an African medicinal plant. A limonoid 8 and two glycoflavonoids 9-10 were found in its leaves. The metabolites were identified by NMR and MS analyses, and their cytotoxicity was evaluated against the mammalian African monkey kidney (vero), mouse breast cancer (4T1), human larynx carcinoma (HEp2) and human breast cancer (MDA-MB-231) cell lines. Out of the isolates, oleanonic acid (2) showed the highest cytotoxicity, i.e., IC50's of 1.4 and 13.3 µM against the HEp2 and 4T1 cells, respectively. Motivated by the higher cytotoxicity of the crude bark extract as compared to the isolates, the interactions of oleanonic acid (2) with five triterpenoids 3-7 were evaluated on vero cells. In an antiplasmodial assay, seven of the metabolites were observed to possess moderate activity against the D6 and W2 strains of P. falciparum (IC50 27.1-97.1 µM), however with a low selectivity index (IC50(vero)/IC50(P. falciparum-D6)<10). The observed moderate antiplasmodial activity may be due to general cytotoxicity of the isolated triterpenoids.
authors.affiliation: Kenya Medical Research Institute, Centre for Traditional Medicine and Drug Research, P.O. Box 54840-00200, Nairobi 00200, Kenya. jmidiwo@uonbi.ac.ke.
authors.forename: Beatrice N
authors.initials: BN
authors.lastname: Irungu
authors.affiliation: Kenya Medical Research Institute, Centre for Traditional Medicine and Drug Research, P.O. Box 54840-00200, Nairobi 00200, Kenya. JOrwa@kemri.org.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Orwa
authors.affiliation: Sahlgrenska Cancer Centre, University of Gothenburg, Gothenburg SE-405 30, Sweden. amragruhonjic@hotmail.com.
authors.forename: Amra
authors.initials: A
authors.lastname: Gruhonjic
authors.affiliation: Sahlgrenska Cancer Centre, University of Gothenburg, Gothenburg SE-405 30, Sweden. paul.fitzpatrick@gu.se.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Fitzpatrick
authors.affiliation: Sahlgrenska Cancer Centre, University of Gothenburg, Gothenburg SE-405 30, Sweden. goran.landberg@gu.se.
authors.forename: Göran
authors.initials: G
authors.lastname: Landberg
authors.affiliation: Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi 00200, Kenya. FKimani@kemri.org.
authors.forename: Francis
authors.initials: F
authors.lastname: Kimani
authors.affiliation: Department of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi 00100, Kenya. jmidiwo@uonbi.ac.ke.
authors.forename: Jacob
authors.initials: J
authors.lastname: Midiwo
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg SE-412 96, Sweden. mate@chem.gu.se.
authors.forename: Máté
authors.initials: M
authors.lastname: Erdélyi
authors.affiliation: Department of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi 00100, Kenya. ayenesew@uonbi.ac.ke.
authors.forename: Abiy
authors.initials: A
authors.lastname: Yenesew
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000302:isolation & purification / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D006801:Humans; D029582:Meliaceae / Q000737:chemistry*; D051379:Mice; D021261:Parasitic Sensitivity Tests; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry*; D010963:Plasmodium falciparum / Q000187:drug effects*; D014709:Vero Cells
chemical_list: D000962:Antimalarials; D010936:Plant Extracts