title: Evaluation of Antiplasmodial activity of extracts and constituents from Ampelozizyphus amazonicus.
abstract: BACKGROUND
  Ampelozizyphus amazonicus Ducke, a plant that is widely used by the population of the Amazonian region to prevent and treat malaria, was investigated in this work, which describes, for the first time, the antiplasmodial activity of its extracts and associates this activity with its isolated constituents.
  
  
  METHODS
  Different extracts with solvents of increasing polarity (hexane, chloroform, ethanol, and water) were obtained of the root bark. This procedure resulted in extracts that were characterized for their constituents. The cytotoxicity and activity of the extracts against Plasmodium berghei (schizontocidal activity, liver stage) and Plasmodium falciparum (3D7 and Dd2 strains, erythrocyte stage) were assessed in vitro.
  
  
  RESULTS
  Of the four extracts assayed against P. berghei, the chloroform extract showed the greatest activity, with an inhibitory concentration 50% (IC50) value of 30.1 µg/mL, followed by the aqueous extract (IC50 = 39.9 µg/mL). The chloroform extract exhibited the highest antiplasmodial activity in the erythrocyte stage of P. falciparum, with an IC50 value lower than 15 µg/mL. Fractionation of this more active extract led to the isolation and elucidation of pentacyclic triterpenes, lupeol, betulin and betulinic acid, which showed antiplasmodial activities with IC50 values ranging from 5.6 to 80.30 µM. The most active of these, betulinic acid, was further quantified in the extracts by high-performance liquid chromatography-photodiode array detector analyzes. The higher amount was found in the chloroform extract, which was the most active one against P. falciparum.
  
  
  CONCLUSIONS
  The results obtained in this work may partly explain the popular intake of A. amazonicusas an antimalarial remedy in the Amazon region.
authors.affiliation: Department of Chemistry, Chromatography Laboratory, Federal University of Amazonas (UFAM), Rodrigo Otavio Avenue, 3000, Academic Campus, 69077-000, Manaus, Amazonas, Brazil.
authors.forename: Dominique F M
authors.initials: DF
authors.lastname: do Carmo
authors.affiliation: Department of Natural Products, Medicinal Plants and Derivatives Laboratory, Farmanguinhos, Oswaldo Cruz Foundation (FIOCRUZ), Sizenando Nabuco Street, 100, Manguinhos, 21041-250, Brazil.
authors.forename: Ana Claudia F
authors.initials: AC
authors.lastname: Amaral
authors.affiliation: Parasitology Unit, Center of Studies on Malaria and Other Tropical Diseases, LA, Institute Hygiene and Tropical Medicine from the New University of Lisbon, Junqueira street, 100, 1349-008 Lisboa, Portugal, Brazil.
authors.forename: Marta
authors.initials: M
authors.lastname: Machado
authors.affiliation: Parasitology Unit, Center of Studies on Malaria and Other Tropical Diseases, LA, Institute Hygiene and Tropical Medicine from the New University of Lisbon, Junqueira street, 100, 1349-008 Lisboa, Portugal, Brazil.
authors.forename: Dinora
authors.initials: D
authors.lastname: Lopes
authors.affiliation: Department of Chemistry, Federal Rural University of Rio de Janeiro (UFRRJ) Km 47, Seropedica, 23851970, Rio de Janeiro, RJ, Brazil.
authors.forename: Aurea
authors.initials: A
authors.lastname: Echevarria
authors.affiliation: Parasitology Unit, Center of Studies on Malaria and Other Tropical Diseases, LA, Institute Hygiene and Tropical Medicine from the New University of Lisbon, Junqueira street, 100, 1349-008 Lisboa, Portugal, Brazil.
authors.forename: Virgílio E
authors.initials: VE
authors.lastname: Rosário
authors.affiliation: Department of Chemistry, Chromatography Laboratory, Federal University of Amazonas (UFAM), Rodrigo Otavio Avenue, 3000, Academic Campus, 69077-000, Manaus, Amazonas, Brazil.
authors.forename: Jefferson Rocha de A
authors.initials: JR
authors.lastname: Silva
keywords: Ampelozyziphus amazonicus; antimalarial activity; rhamnaceae; triterpenes