title: Synergism between quinine and retinol in fresh isolates of Plasmodium falciparum.
abstract: Following earlier reports of synergism between retinol and various antimalarial compounds, the pharmacodynamic interaction between retinol and quinine was investigated in 38 fresh isolates of Plasmodium falciparum. The study was carried out in western Thailand, an area with quinine-resistant P. falciparum. The combination of quinine with retinol in concentrations corresponding to the 50(th), 65(th) and 80(th) percentile of the physiological values in healthy subjects, significantly reduced the EC(50), EC(90), EC(99) and GMCOC for quinine. The FIC values at EC(90) and EC(99) indicate increasing synergism with rising EC and retinol concentration. The mean SFIC value dropped to a level as low as 0.2420, indicating strong synergism.
authors.affiliation: Department of Medical Parasitology, Institute of Hygiene, Medical University of Graz, Austria.
authors.forename: Ariane
authors.initials: A
authors.lastname: Knauer
authors.forename: Kanungnit
authors.initials: K
authors.lastname: Congpuong
authors.forename: Gunther
authors.initials: G
authors.lastname: Wernsdorfer
authors.forename: Franz F
authors.initials: FF
authors.lastname: Reinthaler
authors.forename: Jeeraphat
authors.initials: J
authors.lastname: Sirichaisinthop
authors.forename: Walther H
authors.initials: WH
authors.lastname: Wernsdorfer
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D002648:Child; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D004357:Drug Synergism; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D016778:Malaria, Falciparum / Q000188:drug therapy / Q000469:parasitology*; D008297:Male; D008875:Middle Aged; D002052:Myanmar; D021261:Parasitic Sensitivity Tests; D010963:Plasmodium falciparum / Q000187:drug effects*; D011803:Quinine / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D013785:Thailand; D014801:Vitamin A / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D014815:Vitamins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000962:Antimalarials; D014815:Vitamins; D014801:Vitamin A; D011803:Quinine