Phytomedicine Phytomedicine 10: 490–493, 2003 © Urban & Fischer Verlag http://www.urbanfischer.de/journals/phytomed 0944-7113/03/10/06–07-490 $ 15.00/0  Introduction Chagas’disease (American trypanosomiasis), a pathol- ogy caused by the flagellate protozoan Trypanosoma cruzi, is endemic in Latin America and affects 16–18 million people, with more than 100 million exposed to the risk of infection (Coura and Castro, 2002). In Brazil, about 5–6 million people are infected, 300 000 of them living in São Paulo State (Canesin and Barret- to, 1997). At present, with insect vector population control, infected blood transfusion is becoming the major mechanism of transmission (Ramirez et al. 1995). The only trypanocidal substance used currently to prevent infection in blood banks is gentian violet (Nussensweig et al. 1953) but, due to its undesirable ef- fects, its use as a trypanocidal agent is limited. Thus, the search for new effective compounds that do not af- fect red blood cells is the main goal in the prevention of Chagas’ disease. During a program developed to discover new natural compounds with this activity, our group and other in- vestigators have obtained results indicating that Ly- chnophora sp. is a source of active natural agents. Iso- lated constituents, such as flavonoids and sesquiter- pene lactones, have exhibited trypanocidal activity in vitro (Chiari et al. 1991; Chiari et al. 1996; Oliveira et al. 1996; Jordão et al. 1997; Grael et al. 2000). In order to understand the chemistry of the genus and to identify major trypanocidal substances, a bioassay-guided study of Lychnophora staavioides was carried out.  Materials and Methods Plant material L. staavioides was collected in Diamantina (Minas Gerais State, Brazil), in September 1999. The plant ma- terial was identified by Professor João Semir and a voucher specimen (NPL 212) has been deposited in the Herbarium of the Biology Institute of the Universidade Estadual de Campinas (UNICAMP), SP, Brazil. Extraction procedures Dried and powdered leaves (2.1 kg), stem (1.6 kg), stem bark (1.4 kg), branches (2.9 kg), and roots (0.7 kg) were extracted exhaustively with methanol and Trypanocidal activity of Lychnophora staavioides Mart. (Vernonieae, Asteraceae) R. Takeara 1 , S. Albuquerque 2 , N. P. Lopes 1 , and J. L. C. Lopes 1 1 Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto - USP, Ribeirão Preto, SP, Brazil 2 Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto – USP, Ribeirão Preto, SP, Brazil Summary In the continuing search for new compounds with trypanocidal activity for use in blood banks to prevent the transmission of Chagas’ disease, a trypanocidal extract of Lychnophora staavioides Mart. (Vernonieae, Asteraceae) was fractionated using several chromatographic techniques and afforded the following flavonoids: tectochrysin, pinostrobin, pinobanksin, pinobanksin 3-acetate, pinocembrin, chrysin, galangin 3-methyl ether, quercetin 3-methyl ether, chrysoeriol and vicenin- 2. The most active compound was quercetin 3-methyl ether, which showed no blood lysis activity and which represents a promising compound for use against T. cruzi in blood banks. Key words: Lychnophora staavioides, trypanocidal activity, flavonoids