Qualea grandiflora Mart. (“pau-terra”) is a medicinal plant symbolic from Cerrado biome. Qualea species reportedly have antiparasitic properties, but their active compounds have yet to be identified. In this study, we investigated the antiplasmodial activity of Q. grandiflora fruit and stem extracts against Plasmodium falciparum. The polar extracts of both fruits and stems showed promising in vitro antiplasmodial activity against sensitive and resistant P. falciparum strains (half-maximal inhibitory concentration (IC50) = 1.2 and 4.2 ng mL-1, respectively), low cytotoxicity against human hepatic cells (IC50HepG2 ≥ 400 ng mL-1), and a noteworthy selectivity index (SI ≥ 322 and ≥ 96, respectively). The fruit ethanolic extract revealed significant oral efficacy at 100 mg kg-1 in a mouse model of P. berghei malaria (100% reduction in parasitemia on day 5 post-infection). To investigate the chemical composition of the extracts, we developed a method involving liquid chromatography-high resolution quadrupole-time of flight mass spectrometer. The chemical profiling of active extracts indicated 32 compounds, including gallotannins, ellagic acid derivatives and flavonoids. The common component in the active polar extracts was found to be ellagic acid (EA), which may contribute favorably to the in vitro and in vivo inhibitory activity observed in this study.

A chemical investigation of two specimens of Byrsonima coccolobifolia collected in the southeast cerrado and from central Brazil was performed. A new degraded diterpenoid, byrsonimaquinone, was isolated from the stems along with known compounds. This is the first study on the roots of B. coccolobifolia, and several triterpenes, such as α-amyrin, β-amyrin, oleanolic acid, and glochidonol, along with a mixture of stigmasterol, β-sitosterol and campesterol, were identified. These compounds were identified by spectroscopic analysis techniques, including 1D and 2D NMR, GC-MS and high-resolution mass spectrometry.

Ácidos galoilquínicos, substâncias que têm apresentado atividade leishmanicida, foram isolados do extrato de acetato de etila da planta Byrsonima coccolobifolia. Estes compostos fenólicos juntamente com o ácido gálico demonstraram ser uma nova classe de inibidores não-competitivos potentes em arginase (ARG) de Leishmania amazonensis (Ki variando de 0,10 a 0,68 µmol L-1). O ácido quínico não apresentou atividade inibitória significativa em ARG demonstrando que a unidade galoila tem características importantes que permitem a interação enzima-inibidor. A atividade inibitória significativa do ácido gálico frente à ARG pode ser uma indicação para o entendimento da resposta imune previamente observada em Leishmania donovani, uma vez que a atividade enzimática da arginase está associada à diminuição dos níveis de NO no processo de infecção por Leishmania.

Leishmanicidal galloylquinic acids were isolated from the ethyl acetate extract of Byrsonima coccolobifolia. These phenols and gallic acid showed to be a new class of potent noncompetitive inhibitors of arginase ARG (Ki ranging from 0.10 to 0.68 µmol L-1) from Leishmania amazonensis. Quinic acid did not exhibit significant inhibition of ARG, indicating that galloyl moiety has important features that allows the enzyme-inhibitor interactions. The significant inhibitory activity of gallic acid on ARG can be a clue to understand the immune response previously observed on L. donovani, since ARG activity is associated with the decrease of the levels of NO in Leishmania infection.