Pharmacology & Pharmacy, 2011, 2, 47-55 doi:10.4236/pp.2011.22006 Published Online April 2011 (http://www.SciRP.org/journal/pp) Copyright © 2011 SciRes. PP 47 Antitrypanosomal Activity of a Semi-Purified Subfraction Rich in Labdane Sesquiterpenes, Obtained from Flowers of Anthemis tinctoria, against Trypanosoma cruzi Nilza de Lucas Rodrigues Bittencourt 1 , Tânia Ueda-Nakamura 1,2 , Benedito Prado Dias Filho 1,2 , Celso Vataru Nakamura 1,2 1 Programa de Pós-graduação em Ciências Farmacêuticas; 2 Departamento de Ciências Básicas da Saúde, Laboratório de Inovação Tecnológica no Desenvolvimento de Fármacos e Cosméticos, Universidade Estadual de Maringá, Maringá, Paraná, Brazil. Email: cvnakamura@gmail.com Received September 27 th , 2010; revised December 15 th , 2010; accepted December 29 th , 2010. ABSTRACT In Brazil and several other Latin American countries, Chagas’ disease still constitutes a serious medical and social problem, and there is a need to develop new, more-potent drugs with fewer side effects to effectively treat this disease. We investigated the antitrypanosomal effect of a crude extract, fractions, and a semi-purified subfraction rich in a mix- ture of isomeric labdane sesquiterpenes, obtained from flowers of Anthemis tinctoria, against Trypanosoma cruzi. In epimastigote forms, the aqueous crude extract, dichloromethane fraction, and semi-purified subfraction showed a dose-dependent inhibitory activity, with IC 50 of 2.3 μg/ml, 1.8 μg/ml, and 0.2 μg/ml, respectively. In the interaction in- dex, the semi-purified subfraction showed a reduction in both the percentage of infected LLCMK 2 cells and the mean number of amastigotes per infected cell. The cytotoxicity evaluation demonstrated that the cytotoxic concentrations of the semi-purified subfraction were higher for LLCMK 2 cells than for the protozoans, with a selectivity index of 35.0. Epimastigote forms treated with the semi-purified subfraction showed ultrastructural and morphological alterations such as rounding of the cells and bleb formation in the flagellum and cytoplasmic membrane. These results show that the flowers from A. tinctoria may be a source of new drugs with antiprotozoal activity. However, additional in vitro and in vivo studies are needed to validate the use of A. tinctoria in the treatment of Chagas’ disease. Keywords: Antiprotozoan Activity, Medicinal Plants, Trypanosoma cruzi, Ultrastructure Alterations 1. Introduction About 65% - 80% of the population in developing countries essentially depends on plants for primary health care. Some 25% of all modern medicines are derived directly or indirectly from plants [1]. Many plants from Brazilian ecosystems such as the savanna, and the Atlantic and Amazon forests are used in traditional medi- cine [2]. Also, many exotic plants that were introduced into Brazil and incorporated into traditional medicine display curative properties [3]. Various studies have demonstrated a strong correlation between popular use and experimenttally demonstrated pharmacological acti- vity. Many plant extracts and essential oils have been shown to exert in vitro and in vivo activity, which jus- tifies research on plants used in traditional medicine [4]. Plants produce a variety of compounds with antimi- crobial properties, which have led to the development of new drugs for treatment of infectious diseases [5]. The family Compositae is one of the most species-rich among the flowering plants. Anthemis L. is the second- largest genus in this family with approximately 25 000 species, widely distributed in subtropical and temperate areas. Species of Anthemis are widely used in the phar- maceutical, cosmetic and food industries. Anthemis tinc- toria L. is a perennial herb cultivated in Mediterranean countries, and several secondary metabolites have been identified in this species, such as volatile oils, triterpenes, polyacetylenes, and flavonoids [6]. In traditional medi- cine, this plant is used to treat liver problems and jaun- dice [7]. Its flowers have well-known antiseptic and me- dicinal properties, derived from flavonoids as well as es-