title: In vitro and in vivo antimalarial activity and cytotoxicity of extracts, fractions and a substance isolated from the Amazonian plant Tachia grandiflora (Gentianaceae).
abstract: Tachia sp. are used as antimalarials in the Amazon Region and in vivo antimalarial activity of a Tachia sp. has been previously reported. Tachia grandiflora Maguire and Weaver is an Amazonian antimalarial plant and herein its cytotoxicity and antimalarial activity were investigated. Spectral analysis of the tetraoxygenated xanthone decussatin and the iridoid aglyone amplexine isolated, respectively, from the chloroform fractions of root methanol and leaf ethanol extracts was performed. In vitro inhibition of the growth of Plasmodium falciparum Welch was evaluated using optical microscopy on blood smears. Crude extracts of leaves and roots were inactive in vitro. However, chloroform fractions of the root and leaf extracts [half-maximal inhibitory concentration (IC50) = 10.5 and 35.8 µg/mL, respectively] and amplexine (IC50= 7.1 µg/mL) were active in vitro. Extracts and fractions were not toxic to type MRC-5 human fibroblasts (IC50> 50 µg/mL). Water extracts of the roots of T. grandiflora administered by mouth were the most active extracts in the Peters 4-day suppression test in Plasmodium berghei-infected mice. At 500 mg/kg/day, these extracts exhibited 45-59% inhibition five to seven days after infection. T. grandiflora infusions, fractions and isolated substance have potential as antimalarials.
authors.affiliation: Laboratório de Princípios Ativos da Amazônia, Coordenação de Tecnologia e Inovação, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brasil.
authors.forename: Luiz Francisco Rocha e
authors.initials: LF
authors.lastname: Silva
authors.forename: Emerson Silva
authors.initials: ES
authors.lastname: Lima
authors.forename: Marne Carvalho de
authors.initials: MC
authors.lastname: Vasconcellos
authors.forename: Ellen Suzany Pereira
authors.initials: ES
authors.lastname: Aranha
authors.forename: David Siqueira
authors.initials: DS
authors.lastname: Costa
authors.forename: Elba Vieira
authors.initials: EV
authors.lastname: Mustafa
authors.forename: Sabrina Kelly Reis de
authors.initials: SK
authors.lastname: Morais
authors.forename: Maria das Graças Costa
authors.initials: Md
authors.lastname: Alecrim
authors.forename: Sergio Massayoshi
authors.initials: SM
authors.lastname: Nunomura
authors.forename: Lena
authors.initials: L
authors.lastname: Struwe
authors.forename: Valter Ferreira
authors.initials: VF
authors.lastname: de Andrade-Neto
authors.forename: Adrian Martin
authors.initials: AM
authors.lastname: Pohlit
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000302:isolation & purification / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects*; D029965:Gentianaceae / Q000737:chemistry*; D006801:Humans; D020128:Inhibitory Concentration 50; D051379:Mice; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000187:drug effects*
chemical_list: D000962:Antimalarials; D010936:Plant Extracts