title: Antimalarial activity and toxicity evaluation of a quantified Nauclea pobeguinii extract.
abstract: OBJECTIVE
  To evaluate the in vitro and in vivo antiplasmodial activity and toxicity of the aqueous and 80% EtOH extract of the stem bark of Nauclea pobeguinii (Pob. Ex. Pell.) Petit (Rubiaceae), a plant used in traditional medicine in DR Congo against malaria.
  
  
  METHODS
  The aqueous and 80% EtOH extract from N. pobeguinii stem bark, and its constituents (5S)-5-carboxystrictosidine, 19-O-methylangustoline, 3-O-beta-fucosylquinovic acid, 3-ketoquinovic acid and strictosamide, were evaluated for their in vitro activity against Plasmodium falciparum (chloroquine-sensitive Ghana-strain). The 80% EtOH extract, containing 5.6% strictosamide, was evaluated in vivo in the 4-day P. berghei mouse model, and in the P. yoelii N67 model.
  
  
  RESULTS
  All compounds were inactive or only moderately active in vitro. The aqueous and 80% EtOH extract displayed moderate in vitro activity with IC(50) values of 44 and 32 microg/mL, respectively, without apparent cytotoxicity on MRC-5 cells (CC50>64 microg/mL). Daily oral dosing of the 80% EtOH extract, at 300 mg/kg, resulted in 86% reduction of parasitaemia in the 4-day P. berghei mouse model, and 75% reduction in the P. yoelii N67 model. Prolonging oral dosing to 2 x 5 days, with an interval of 2 days, and oral administration of the 80% EtOH extract at 300 mg/kg induced 92% reduction of parasitaemia, and a mean survival time of 17 days. Strictosamide, the putative active constituent, may be metabolically activated in the gastrointestinal tract after oral administration. Levels of creatinin, urea, ALAT and ASAT remained unchanged after treatment. No acute toxicity was observed in mice after a single 2g/kg oral dose, nor after 4 weekly doses. No significant macroscopic or microscopic lesions were observed in heart, lung, spleen, kidney, liver, large intestine and brain.
  
  
  CONCLUSIONS
  These results can partly support and justify the use of N. pobeguinii in traditional medicine in the DR Congo for the treatment of uncomplicated malaria.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Kinshasa, P.O. Box 212, Kinshasa XI, Democratic Republic of the Congo.
authors.forename: Kahunu
authors.initials: K
authors.lastname: Mesia
authors.forename: Richard K
authors.initials: RK
authors.lastname: Cimanga
authors.forename: Liene
authors.initials: L
authors.lastname: Dhooghe
authors.forename: Paul
authors.initials: P
authors.lastname: Cos
authors.forename: Sandra
authors.initials: S
authors.lastname: Apers
authors.forename: Jozef
authors.initials: J
authors.lastname: Totté
authors.forename: Gaston L
authors.initials: GL
authors.lastname: Tona
authors.forename: Luc
authors.initials: L
authors.lastname: Pieters
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Vlietinck
authors.forename: Louis
authors.initials: L
authors.lastname: Maes
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000302:isolation & purification / Q000633:toxicity*; D002478:Cells, Cultured; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005260:Female; D006801:Humans; D051379:Mice; D024301:Plant Bark; D010936:Plant Extracts / Q000302:isolation & purification / Q000633:toxicity*; D018547:Plant Stems; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000254:growth & development*; D011897:Random Allocation; D019666:Rubiaceae; D023382:Toxicity Tests, Acute / Q000379:methods
chemical_list: D000962:Antimalarials; D010936:Plant Extracts