title: In vitro activity of artemisinin alone and in combination with retinol against Plasmodium falciparum.
abstract: Increasing resistance of Plasmodium falciparum to antimalarial drugs is an important public health problem, demanding novel therapeutic approaches. This study had the objective of assessing the in vitro activity of artemisinin and its combination with retinol in fresh isolates of P. falciparum in an area with a high proportion of multidrug-resistant strains. The tests were based on the inhibition of schizont maturation. In 45 successfully tested isolates, the mean effective concentrations (ECs) of artemisinin were 10.29 nM for the EC-50 and 34.86 nM for the EC-90. The EC50 and EC90 for artemisinin in the artemisinin-retinol mixture were 2.71 nM and 13.37 nM, respectively. The combination showed synergistic activity. Retinol appears to be a promising partner for the antimalarial therapy with artemisinins.
authors.affiliation: Institute of Specific Prophylaxis and Tropical Medicine, Center for Physiology and Pathophysiology, Medical University Vienna, Vienna, Austria.
authors.forename: Kamala
authors.initials: K
authors.lastname: Thriemer
authors.forename: Gunther
authors.initials: G
authors.lastname: Wernsdorfer
authors.forename: Chaiporn
authors.initials: C
authors.lastname: Rojanawatsirivet
authors.forename: Herwig
authors.initials: H
authors.lastname: Kollaritsch
authors.forename: Jeeraphat
authors.initials: J
authors.lastname: Sirichainsinthop
authors.forename: Walther H
authors.initials: WH
authors.lastname: Wernsdorfer
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage; D000962:Antimalarials / Q000008:administration & dosage; D037621:Artemisinins / Q000008:administration & dosage*; D002648:Child; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004351:Drug Resistance; D004357:Drug Synergism; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000469:parasitology*; D008297:Male; D021261:Parasitic Sensitivity Tests; D010963:Plasmodium falciparum / Q000166:cytology / Q000187:drug effects* / Q000302:isolation & purification*; D012717:Sesquiterpenes / Q000008:administration & dosage*; D016896:Treatment Outcome; D014801:Vitamin A / Q000008:administration & dosage*
chemical_list: D000890:Anti-Infective Agents; D000962:Antimalarials; D037621:Artemisinins; D004338:Drug Combinations; D012717:Sesquiterpenes; D014801:Vitamin A; C031327:artemisinin