title: The use of microfluorometric method for activity-guided isolation of antiplasmodial compound from plant extracts.
abstract: In vitro antiplasmodial activity of methanolic extracts of 16 medicinal plants was evaluated by fluorometric assay using PicoGreen. The IC50s, as determined by parasite DNA concentration, ranged from <11 to >200 and <13 to >200 microg/ml for Plasmodium falciparum 3D7 and K1, respectively; and the most active extracts were those from Anogeissus leiocarpus and Terminalia avicennoides (<11-> or =14 microg/ml). Aqueous, butanolic, ethyl acetate, and methanolic fractions of these two extracts revealed butanolic fraction to have a relatively better activity (IC50, 10-12 microg/ml). Activity-guided chromatographic separation of the butanolic fraction on Sephadex LH-20 followed by nuclear magnetic resonance and correlation high-performance liquid chromatography revealed the presence of known hydrolysable tannins and some related compounds-castalagin, ellagic acid, flavogallonic acid, punicalagin, terchebulin, and two other fractions. The IC50s of all these compounds ranged between 8-21 microg/ml (8-40 microM) against both the strains. Toxicity assay with mouse fibroblasts showed all the extracts and isolated compounds to have IC50 > or = 1500 microg/ml, except for Momordica balsamina with <1500 microg/l. All the extracts and isolated compounds did not affect the integrity of human erythrocyte membrane at the observed IC50s. However, adverse effects manifest in a concentration-dependent fashion (from IC50 > or = 500 microg/ml).
authors.affiliation: Department of Natural Product Chemistry, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki-shi, Japan, nshuaibu@yahoo.com
authors.forename: M N
authors.initials: MN
authors.lastname: Shuaibu
authors.forename: P A
authors.initials: PA
authors.lastname: Wuyep
authors.forename: T
authors.initials: T
authors.lastname: Yanagi
authors.forename: K
authors.initials: K
authors.lastname: Hirayama
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: I
authors.initials: I
authors.lastname: Kouno
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology* / Q000633:toxicity; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004912:Erythrocytes / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D005470:Fluorometry / Q000379:methods*; D006801:Humans; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry; D010963:Plasmodium falciparum / Q000187:drug effects*
chemical_list: D000962:Antimalarials; D010936:Plant Extracts