RESUMO
Excessive generation of reactive oxygen species (ROS) by polymorphonuclear leukocytes (PMNL) is involved in the pathology of many inflammatory diseases. Compounds isolated from natural sources with antioxidant activity can be helpful to inhibit and/or modulate the oxidative damage associated with PMNL-derived ROS. The present study investigated the relationship between the chemical structure of five methoxylated flavonoids, isolated from Chromolaena hirsuta and Chromolaena squalida, and their inhibitory activity on ROS generation by opsonized zymosan-stimulated PMNL. The antioxidant efficacy of the studied flavonoids, assessed by luminol-dependent chemiluminescence, was dependent on the position and number of methoxy and hydroxy groups.
Assuntos
Chromolaena/química , Flavonoides/química , Flavonoides/farmacologia , Fatores Imunológicos/farmacologia , Animais , Feminino , Fatores Imunológicos/química , Leucócitos Mononucleares/efeitos dos fármacos , Estrutura Molecular , Coelhos , Espécies Reativas de Oxigênio , Relação Estrutura-AtividadeRESUMO
Phytochemical study of Chromolaena hirsuta (Hook. & Arn.) R. King & H. Robinson crude extract (collected in Furnas, MG-Brasil) produced fifteen flavonoids, two triterpenes and five steroids. IR, UV,(1)H and (13)C NMR spectroscopy and GC analysis were used for the identification of these compounds. The dichloromethanic and ethanolic crude extracts (flowers and leaves) and six flavonoids isolated from this specie have been assayed for antiprotozoal activity against tripomastigote forms of Trypanosoma cruzi and promastigote forms of Leishmania amazonensis. The crude extracts significantly reduced the viability of T. cruzi and Leishmania amazonensis, and the six flavonoids showed considerable antiproliferative effect of development of two parasites evaluated. This is the fi rst report of antiprotozoal activity of extracts of C. hirsuta.
