Estudos químicos de extratos bioativos de piquiá (Caryocar villosum (Aubl.) Pers.)

Abstract

The amazonian fruit residues are promising sources of chemical and metabolites constituents that are responsible for various biological activities. Many of these substances are able to inhibit the growth of microorganisms that cause infectious diseases. Among these fruits, the piquiá (Caryocar villosum) is a native fruit of the Amazonian Forest, a species belonging to the family Caryocaraceae, much appreciated for its pulpy flesh and excellent quality of its wood. Recent studies describe bioactive substances in ethanolic and hydroalcoholic extracts of bark and seeds that have antioxidant, enzymatic and photoprotective properties. The present work studied the chemical composition of the bioactive extracts of peels and seeds of piquiá. After cleaning, drying and grinding, the peels and pulverized seeds were extracted by maceration and Soxhlet with ethanol and, comparatively, with increasing polarity solvents (hexane, ethyl acetate and methanol). The ethanolic extracts were submitted to the liquid-liquid partition with hexane, dichloromethane, ethyl acetate and methanol. All the extracts and fractions were submitted to tests in Fiocruz to evaluate the antibacterial activity by agar diffusion technique against Gram positive and negative bacteria and for antiplasmodial evaluation by flow cytometry. In biological activity tests, the FASP fraction was moderately active against the bacteria Staphylococcus aureus (12 mm), methicillin resistant Staphylococcus aureus (12 mm) and Shigella flexneri (15 mm), while the FHCP, EMCP, EMSP and EECP samples showed low activity against the bacterium Shigella flexneri with inhibition halos 11 mm, 11 mm, 10 mm and 9 mm, respectively. In the antiplasmodial evaluation only the EACP extract showed significant inhibition of the parasite Plasmodium falciparum, with a percentage of parasite inhibition above 60% in all concentrations tested. The phytochemical study of the bioactive samples was performed by chromatographic techniques and the identification of the substances was performed by spectroscopic and spectroscopic techniques. In the thin layer chromatography (TLC) analyzes of the samples, bands with characteristic coloration of phenolic compounds, flavonoids, saponins and terpenes were observed. The FHCP sample was analyzed by TLC and fractionated by flash column chromatography, one of the fractions was identified as a mixture of the phytosterols β-sitosterol and stigmasterol by the spectrometric analyzes in comparison of the data with the literature. Chromatographic, spectroscopic and spectrometric data of the FASP fraction and the EMCP / EMSP / EACP extracts compared to the literature data allowed to identify the presence of gallic and ellagic acid derivatives and may be the main compounds responsible for the bioactivity of extracts and fractions of the fruit.