Estudo químico dos extratos ativos de bacuri (Platonia insignis)

Abstract

The researches aimed at understanding the benefits that fruit consumption gives us has grown considerably and the dissemination of the nutritional and therapeutic potential of these has intensified these researches and recognized the Amazon as an excellent field for the search for new bioactive compounds. With this, the consumption of the fruits has been increased, which generates a quantity of residues, barks and seeds, many times more than the quantity used for consumption. These wastes are usually only disposed of in the environment turning in to pollution. In an attempt to reduce the pollution generated, we have worked on projects that reuse the fruit residues. One of the fruits that stands out in these studies is bacuri, an Amazonian fruit produced by Platonia insignis Mart, Clusiaceae family, which, when analyzing its ethanolic extracts, presented relevant results in the tests for evaluation of biological activities. Therefore, the present work had the objective of isolating and identifying the main chemical constituents of bacuri waste extracts by methods of chromatographic, mass spectrometry (EM) and nuclear magnetic resonance (NMR) techniques. In this study the ethanolic extracts of the seeds and peels were partitioned using solvents with different polarities: hexane, dichloromethane and attila acetate. The hexane phase of the ethanolic extracts of bacuri bark (EECB) was submitted to chromatographic fractions. From this fraction, the substances HB3C, HC24, HC344 and HE129 were isolated. Of these substances only HC24 was elucidated. This showed typical phenolic chromatographic behavior, the molecular ion peak was in m/z 603 in APCI in the positive mode and presented chemical shifts that, when analyzed and compared to the literature data, this substance could be identified as being Garcinielliptona FC (GFC), a prenylated benzophenone rich in biological activities. The HE129 substance was analyzed from the chromatographic and mass spectrometry data and it was possible to observe behavior similar to that of GFC showing molecular ion peak in m/z 603 in APCI in the positive mode and the fragments characteristic of the presence of another isomer of GFC, however, the NMR data analysis could not be performed because of the small amount of mass in the sample. The dichloromethane fraction of the ethanolic extract of bacuri seeds (EESB) was also submitted to chromatographic fractions from which the substances 6a1, 7a1 and 7c1 were obtained. Substance 6a1 was shown as a white solid. This substance was subjected to recrystallization analysis and, through the chromatographic data, the MS and NMR data could be identified as 30-epi-cambogin, plus a prenylated benzophenone, common in the Clusiaceae family, but not yet reported in the species. The substance 7a1 and 7c1 appeared as a yellow amorphous solid. When analyzed by thin layer chromatography, it was observed that the substance 7a1 was still in a mixture, but the analysis of its mass spectrum and chromatographic behavior suggests that it is classified as a phenolic, but it was not possible to elucidate the structure. The substance 7c1 identified as a biflavonoid known as fukugetin already described in the fruit. The extracts EECB, EESB, the phases originated from the partition and the isolated and purified substances were submitted to analyzes of antiplasmódic activity measuring the percentage of inhibition of the growth of the malaria parasite, Plasmodium falciparum, and these showed moderate activity.