title: Isolation and identification of antiplasmodial sesquiterpene lactones from Oncosiphon piluliferum.
abstract: Oncosiphon piluliferum (Asteraceae) is used traditionally to treat a variety of ailments, mainly fevers. This prompted the screening of this plant for antiplasmodial properties. The dichloromethane extract of the aerial parts of the plant showed activity in vitro against the chloroquine-sensitive (IC(50) 2.6microg/ml) and the chloroquine-resistant (IC(50) 3.1microg/ml) strains of Plasmodium falciparum. Through conventional chromatographic techniques and bioassay-guided fractionation, sesquiterpene lactones of the germacranolide and eudesmanolide type displaying significant in vitro antiplasmodial activity (IC(50) values ranging from 0.4 to 4.4microg/ml) were isolated and identified by spectroscopic data. In addition, the cytotoxic effects of the active compounds against Chinese Hamster Ovarian (CHO) cells were evaluated and the compounds were found to be toxic to mammalian cells at similar concentrations. Structure-activity relationships were assessed.
authors.affiliation: Biosciences, CSIR, P.O. Box 395, Pretoria 0002, South Africa. ppillay@csir.co.za
authors.forename: Pamisha
authors.initials: P
authors.lastname: Pillay
authors.forename: Robert
authors.initials: R
authors.lastname: Vleggaar
authors.forename: Vinesh J
authors.initials: VJ
authors.lastname: Maharaj
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Smith
authors.forename: Carmen A
authors.initials: CA
authors.lastname: Lategan
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry* / Q000494:pharmacology; D019659:Asteraceae / Q000737:chemistry*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D066298:In Vitro Techniques; D020128:Inhibitory Concentration 50; D007783:Lactones / Q000737:chemistry* / Q000494:pharmacology; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects; D012717:Sesquiterpenes / Q000737:chemistry* / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D000962:Antimalarials; D007783:Lactones; D010936:Plant Extracts; D012717:Sesquiterpenes