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The in vitro trypanocidal activity of a 1 : 4 mixture of lupenone and caryophyllene oxide confirmed a synergistic effect of the terpenoids against epimastigotes forms of T. cruzi (IC50 = 10.4 μg/mL, FIC = 0.46). In addition, testing of the terpenoid mixture for its capacity to reduce the number of amastigote nests in cardiac tissue and skeletal muscle of infected mice showed a reduction of more than 80% at a dose level of 20.8 mg·kg−1·day−1.

The in vitro antimalarial, trypanocidal and leishmanicidal activities and the chemical composition of Ambrosia tenuifolia and A. scabra essential oils were investigated. The oils, obtained by hydrodistillation of the aerial parts, showed significant antimalarial activity against the chloroquine sensitive (F32) and the chloroquine resistant (W2) strains of Plasmodium falciparum with 50% inhibitory concentration (IC 50) values ranged from 2.8 to 7 μg/mL. Against Trypanosoma cruzi epimastigotes, only A. tenuifolia exerted slight activity (IC 50 = 59.7 μg/mL). None of the essential oils showed toxicity towards Leishmania mexicana. Cytotoxicity for murine T-lymphocytes was compared with the parasiticidal activity by using the selectivity index (SI) ratio. The chemical composition of A. tenuifolia and A. scabra essential oils was analyzed by GC-FID-MS. Thirty-eight and twenty-four compounds were identified in A. tenuifolia and A. scabra, respectively. The major constituents of A. tenuifolia oil were germacrene D (22.9%) and bicyclogermacrene (14.2%), while the oil of A. scabra contained limonene (22.0%), caryophyllene oxide (13.8%) and (E)-caryophyllene (13.5%). This is the first time that the antiprotozoal activity of both oils and the chemical composition of A. scabra essential oil have been reported.

Chagas disease is caused by Trypanosoma cruzi and affects the poorest population in the Americas.Fourteen plant extracts and seventeen sesquiterpene lactones from the tribe Vernonieae (Asteraceae), were evaluated for the first time against T. cruzi. Cytotoxicity employing HeLa cells was also assessed. The best results were obtained with leaves and flowers rinse extracts from Vernonanthura nebularum (E-1 and E-3) and Elephantopus mollis (E-11 and E-13), with IC 50 values < 2 µg/mL, being E-1 the most active (IC 50 =0.8 µg/mL). Additionally, these extracts displayed a good selectivity (SI >10). The most active sesquiterpene lactones, isolated from the extracts, were 2 (2-methoxy-2,5-epoxy-8-methacryloxygermacra-3Z,11(13)-dien-6,12-olide) and 6(2-ethoxy-2,5-epoxy-8-angeloxygermacra-3Z,11(13)-dien-6,12-olide) from V. nebularum and 12 (8α-methacryloxyhirsutinolide 13-O-acetate) from V. pinguis,with IC 50 of 1.5, 2.1 and 2.0 µM, respectively. These compounds showed SI values >14, better than those of the reference drug nifurtimox. Plants living in South American ecosystems could become a potential source of trypanocidal agents.

A purificação do extrato da raiz de Colubrina greggii var. yucatanensis levou ao isolamento e identificação do ácido 3-O-acetil ceanótico, um novo triterpeno natural, juntamente com os metabólitos já descritos: ácido ceanótico, ácido cenoténico, ácido betulínico, discarina B e crisofaneína. Os produtos naturais e os derivados semi-sintéticos éster de acetil dimetil ceanotato, dimetil ceanotato e peracetato de crisofaneína mostraram moderada a baixa atividade leishmanicida e tripanocida. Nenhum dos metabólitos mostrou ser citotóxicos ou ter atividade antiproliferativa. Os resultados também sugerem que o ácido betulínico contribui para a atividade antiplasmódica inicialmente detectada na raiz do extrato bruto de C. greggii var. yucatanensis.Purification of the root extract of Colubrina greggii var. yucatanensis resulted in the isolation and identification of 3-O-acetyl ceanothic acid as a new natural ceanothane triterpene, together with the known metabolites ceanothic acid, cenothenic acid, betulinic acid, discarine B and chrysophanein. The natural products and the semisynthetic esters acetyl dimethyl ceanothate, dimethyl ceanothate and chrysophanein peracetate showed moderate to low leishmanicidal and trypanocidal activities. None of the metabolites showed cytotoxic or antiproliferative effects. The results also suggested that betulinic acid contributes to the antiplasmodial activity originally detected in the crude root extract of C. greggii var. yucatanensis. Keywords: Colubrina greggii var. yucatanensis, Rhamnaceae, antiprotozoan, cytotoxic ceanothane IntroductionLeishmaniosis, trypanosomiosis and malaria are a group of protozoan diseases considered of significant importance due to their incidence and rate of mortality in developing countries. 1 The low effectiveness, limited availability and high toxicity of existing treatments for these illnesses emphasize the importance of continuing the search for new antiprotozoan pharmaceuticals.2 Plants are considered an important source of biologically active natural products, 3 including a number of them with antiprotozoan activity. [4][5][6] During the screening of extracts from native Yucatecan medicinal plants as potential sources of bioactive metabolites, the root extract of Colubrina greggii S. Watson var. yucatanensis M. C. Johnst., a shrub used for the treatment of liver diseases, ulcerations, abscesses, asthma and tuberculosis, 7 showedMetabolites from Roots of Colubrina greggii var. yucatanensis J. Braz. Chem. Soc. 1280 trypanocidal, antimalarial, leishmanicidal and cytostatic activity. 8,9 Previous phytochemical studies of the genus Colubrina (Rhamnaceae), which include 31 species, 10 reported the presence of a wide structural diversity of metabolites, including ansa macrolides, saponins, aporphinic alkaloids, phenolic acids, flavones and triterpenoid acids. 11-18To date, only chrysophanol, an anthraquinone with antimicrobial activity, has been reported as a metabolite from C. greggii. 19 In the present study we report the leishmanicidal, trypanocidal, a...

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