0944-7113/04/11/02–03-224 $ 30.00/0 䊏 Introduction The use of medicinal plants in the treatment of infec- tions is an old-age practice. Human infections, parasite and microbial, constitute a serious problem, especially in tropical and subtropical developing countries, de- spite advances in medical science, epidemiology and the discovery of new antibiotics and trypanocidal agents (Portillo et al. 2001). Chagas’ disease is a great health problem in tropical areas of Central and South America. This disease is caused by Trypanosoma cruzi , which is transmitted by house bugs, and it is estimated that at least 20 million people are infected in Brazil alone, with 120,000 new casesbeing diagnosed each year (Phillipson and Wright, 1991). Blood transfusion has also been recog- nized as playing an important role in the transmission of Chagas’ disease in endemic areas (Dias and Brener, 1984; WHO, 1992). Gentian violet is the only available prophylactic drug (Nussensweig et al. 1953). Despite its effectiveness there are some restrictions on its use because this dye turns the blood a purple color, which might stain the skin and mucosa of the recipients. Addi- tionally, a carcinogenic effect has been described in ro- dents, although it has not yet been proved in humans (Wendel and Dias, 1992). The effect of plant-derived and synthetic compounds on T. cruzi has been reported by several authors (Pinto et al. 1987; Moncada et al. 1989), especially of plants from the Asteraceae, such as Senecio sp. (Sarti et al. 1984), Eupatorium sp. (Cardozo and Lopez, 1987), Viguiera sp. (Da Costa et al. 1996) and Lychnophora Trypanocidal and antimicrobial activities of M oquinia kingii E. C. Schinor 1 , M. J. Salvador 1 , I. Y. Ito 3 , S. de Albuquerque 3 , and D. A. Dias 1,2 1 Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Pau Preto – SP, Brasil 2 Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de Sã Ribeirão Preto – SP, Brasil 3 Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas Preto, Universidade de São Paulo, Ribeirão Preto – SP, Brasil Summary A chloroform crude extract (aerial part) and two compounds, apigenin (1) and cynarop isolated from Moquinia kingii were evaluated against Trypanosoma cruzi trypomastigo Antimicrobial activity was also screened using twenty-two strains including Gram-posi Gram-negative bacteria and the yeasts Candida albicans and C. tropicalis. The chlorof extract, fractions and isolated compounds from M. kingii were active for both activitie 50 values for trypanocidal activity obtained for cynaropicrin and apigenin were 93.5 µg/m µg/ml, respectively, while the minimum inhibitory concentrations (MICs) varied from to 2500 µg/ml, against the strains of bacteria and yeasts evaluated. Key words: Moquinia kingii , Asteraceae, trypanocidal activity, antimicrobial activity Phytomedicine 11: 224–229, 2004 http://www.elsevier-deutschland.de/phymed