Contribuições para o conhecimento da composição química e atividade biológica de infusões, extratos e quassinóides obtidos de Picrolemma sprucei Hook.f. (Simaroubaceae)

Abstract

Isobrucein B (2) and neosergeolide (5) are quassinoids which are obtained from Picrolemma sprucei. These compounds have proven in vitro antitumor, antimalarial, anthelminthic, cytotoxic, insecticide and leishmanicidal activities. Herein, in vitro techniques were used to investigate a range of biological activities of 2 and 5 and known semi-synthetic derivative 1,12-diacetylisobrucein B (21) and 12-acetylneosergeolide (22). These compounds were evaluated for general toxicity toward the brine shrimp species Artemia franciscana, cytotoxicity toward human tumour cells, larvicidal activity toward the dengue fever mosquito vector Aedes aegypti and antimalarial activity against the human malaria parasite Plasmodium falciparum. 2 and 5 exhibited the greatest antimalarial activity against multidrug-resistant P. falciparum K1 strain. 2 and 5 (LC50 = 3.2-4.4 mg/L) displayed greater lethality than derivative 22 (LC50 = 75.0 mg/L) toward A. aegypti larvae, while derivative 21 was inactive. Biological assays were also performed with extracts and fractions obtained from P. sprucei fruit. A TLC densitometry method was developed to mensurate the quassinoids content in fruits extracts and fractions. This analysis determinate that only chloroform fractions presents significative content of 2 and 5 and this data is related to the biological activities. Infusions of the stems of P. sprucei are used in the Amazon region as antimalarials. They contain 2 and 5. An LC-(+)-ESI-MS/MS method was developed and applied to the determination of 2 and 5 in P. sprucei infusions. The concentrations of 2 and 5 in the stem infusion were found to be 60.1 and 774 μg L-1, respectively