The trunk bark of Tabebuia caraiba Bignoniaceae was found to contain four novel iridoids, 6-O-E-p-coumaroyljioglutin D (2), 6-O-E-p-coumaroyl-3-demethyl-3-O-ethyljioglutin D (3), 6-O-E-p-coumaroyl-1-demethyl-1-O-ethyljioglutin D (4), 7-O-E-p-coumaroyljiofuranaldehyde (5), three known iridoids, including one iridoid glucoside, jioglutin D (1), rehmaglutin D (6), 6-O-E-p-coumaroylcatalpol (7). From the flowers were obtained six triterpenes, betulinic acid (8), olean-12-en-3-one (9), β-amyrin (10), oleanolic acid (11), ursolic acid (12), 3-O-E-p-coumaroylursolic acid (13), 2α-hydroxyursolic acid (14), 6β,19α-dihydroxyursolic acid (15), and one phenylethanoid, tyrosol (16), in addition to β-sitosterol, β-sitosterol-3-O-β-D-glucopyranoside and β-sitosterol-3-O-β-D-(6´-O-acyl)-glucopyranoside and E-p-coumaric acid. The structures of the isolated compounds were established on the basis of 1D and 2D NMR spectroscopic techniques. The chemical profile of the trunk bark of the plant was determined by HPLC/DAD/HRESIMS and did not present a good correlation with the phytochemical study. It did not detect most of the isolated substances and allowed to propose the presence of some non-isolated compounds.

Resumo A doença de Chagas é uma das principais doenças tropicais negligenciadas causadas pelo Trypanosoma cruzi, e em seu tratamento utilizam-se medicamentos como o nifurtimox e o benzonidazol, que causam vários efeitos colaterais. O mercado de produtos naturais tem aumentado consideravelmente nos últimos anos, e o uso das plantas continua sendo uma alternativa para o desenvolvimento de novos medicamentos para cura de doenças. Portanto, este estudo aborda a composição química do óleo essencial dos frutos verdes de Protium ovatum e a avaliação de seus potenciais tripanocida e citotóxico. O óleo essencial foi obtido por hidrodestilação, utilizando o aparato do tipo Clevenger. A composição química foi determinada por cromatografia gasosa acoplada ao espectrômetro de massas (CG-EM). Os principais compostos encontrados no óleo essencial dos frutos verdes de P. ovatum foram: ß-mirceno (62,0 %), a-pineno (11,3 %) e limoneno (7,3 %). Este é o primeiro relato da composição química do óleo essencial obtido a partir de frutos verdes de P. ovatum. Os resultados mostraram que o óleo essencial analisado apresenta forte atividade tripanocida contra as formas tripomastigota da cepa Y do Trypanosoma cruzi (IC50 = 1,2 µg/mL). O óleo essencial exibiu ainda moderada citotoxidade frente à linhagem LLCMK2 na concentração avaliada (CC50 = 550,3 µg/mL). Em suma, o óleo essencial dos frutos verdes de P. ovatum pode ser considerado uma fonte alternativa para o desenvolvimento de novos medicamentos antiparasitários.

Abstract Chagas disease is a major neglected tropical disease caused by Trypanosoma cruzi. It has been treated with the antiparasitic drugs nifurtimox and benzonidazole, which cause several side effects. The market for natural products has considerably grown lately and the use of plants has become an alternative to the development of novel drugs to cure the disease. Therefore, this study aimed at describing the chemical analysis of the essential oil from green fruits of Protium ovatum and evaluating their trypanocidal and cytotoxic potential. The essential oil was obtained by Clevenger hydrodistillation whereas its chemical composition was determined by gas chromatography coupled to mass spectrometry (GC-MS). The major compounds found in the essential oil from green fruits of P. ovatum were ß-myrcene (62.0 %), a-pinene (11.3 %) and limonene (7.3 %). To the best of our knowledge, this was the first time that the chemical composition of the essential oil from green fruits of P. ovatum was described. Results showed that the essential oil had strong trypanocidal activity against trypomastigote forms of theY strain of Trypanosoma cruzi (IC50 = 1.2 µg/mL). In addition, the essential oil from green fruits of P. ovatum did not display cytotoxicity against LLCMK2 adherent epithelial cell at the concentration range under analysis (CC50 = 550.3 µg/mL). As a result, it is an excellent option for the development of novel antiparasitic drugs.

A new salicylic acid derivative, pentacosanyl salicylate, was isolated from the leaves of the plant toxic to cattle, Riedeliella graciliflora, in addition to a digalactosyldiacylglycerol (DGDG), 1,2-di-O-α-linolenoyl-3-O-α-D-galactopyranosyl-(1→6)-β-D-galactopyranosyl-glycerol, kaempferol-3-O-β-D-glucopyranoside, kaempferol-3-O-α-L-rhamnopyranoside, quercetin-3-O-α-L-rhamnopyranoside, rutin, (+)-catechin and the dimer (+)-catechin-(4β-8)-catechin, glutinol, squalene, β-sitosterol, stigmasterol, phytol, β-carotene, α-tocopherol and ficaprenol-12. Their structures were determined using spectral techniques (MS, IR, and NMR-1D and 2D) and based on literature data.