Investigação fitoquímica com auxílio de molecular networking e atividade citotóxica de Duguetia surinamensis (Annonaceae)

Abstract

The prospect of the discovery of new bioactive substances from plants of the Amazon biome is necessary and may be efficient and selective for the treatment and cure of cancer, once the Annonaceae family is highlighted for presenting bioactive metabolites with cytotoxic action. In this sense, the present work aims to perform the phytochemical study and evaluate the in vitro cytotoxicity of the extracts, fractions, subfractions and substances isolated from the stem bark of D. surinamensis. Initially, the Molecular Networking (MN) tool was used to process data obtained from the Liquid Chromatography Coupled to Mass Spectrometry (LC-MS/MS) analyses of the alkaloid fraction (FA) and subfractions of D. surinamensis in order to examine its chemical profile. The chemical constituents isolated from the FA were identified by spectroscopic (1H and 13C 1D/2D NMR) and spectrometric (MS) techniques. It was also performed the stereochemical determination of two ceded isolates (obtained in the previous study) of this species employing the spectroscopic method of Electronic Circular Dichroism (ECD). Additionally, the extracts, fractions, subfractions and purified substances were submitted to in vitro biological analysis against tumor and non-tumor cells. Five substances were isolated: two aporphinic alkaloids [dicentrinone (S1), duguetine N-oxide (S2)], one morphinanedienone [pallidine (S3)] and two new alkaloids [11-methoxiduguesuramine (S4) and duguesuramine (S5)]. The ceded substances S6 (duguetinine) and S7 (surinasarone) (obtained in the previous study) showed "S" and "R" configuration, respectively, as well as showing specific rotation in the dextrogyre direction. Through the MN analysis of the FA, it was suggested the identification of 26 substances in the FA and 20 substances from the set of samples of the 1st fractionation, totaling 11 unpublished metabolites in the genus Duguetia. Duguetine N-oxide (S2) was most active exhibiting IC50 10.41 μg.mL-1, 7.92 μg.mL-1, 3.58 μg.mL-1, 3.42 μg.mL-1 for HepG2 (human hepatocellular carcinoma), MCF-7 (human breast adenocarcinoma), HL-60 (human promyelocytic leukemia), HCT116 (human colon carcinoma) tumor cells, respectively. For the healthy cell MRC-5 (human lung fibroblast) showed cytotoxicity above the concentration of 12,07 μg.mL-1. Through the results obtained, it was possible to prove that the species D. surinamensis is a promising source of bioactive alkaloids with cytotoxic potential.