Contribuição ao estudo da flora amapaense: avaliação fitoquímica do extrato metanólico das sementes de Vatairea guianensis Aublet

Abstract

The use of medicional plants for diseases treatments is as ancient as human civilization history. Howerver, until nowadays, this practice is predominantly empirical. One of the most traditional species used in Amazon region is Vatairea guianensis Aublet, popularly know as “fava” or “faveira de empigem”. V. guianensis belongs to Fabaceae plant family, one of the largest families in brazilian flora and that holds big economic, ecological and medicinal potential. V. guianensis is traditionally used in woodworks and, in folk medicine, its seeds and leaves are used for skin deasese treatment. This work has aimed to contribute to the knowledge about the native Amapá flora through the realization of a phytochemical study on V. guianensis Aublet seeds methanol extract (EMSVg). The species samples were collect in Mazagão Velho Village, Mazagão Town's district, Amapá state. From the collected samples, an exsiccate was deposited in the Amapá Herbarium – HAMAB, on the record HAMAB-18349, and the seeds were submitted to the Federal University of Paraíba's Pharmaceutical Technology Laboratory for phytochemical analysis. The isolation and purification of the chemical coumpounds were realized through classic chromatograpgy tecniques. Part of EMSVg (0,5 g) was submitted to silica gel 60 column chromatography, Art. 7734 da Merck (0,063-0,200mm), eluted in hexane, ethyl acetate (AcOEt) and methanol (MeOH), pure or in binary mixes, in crescent order of polarity, yielding 96 fractions which were monitored by analytical thin layer chromatography (CCDA) and clustered according to their retention factors (Rfs) similarities. In this process, the fraction Fr-3 was named Vg-1 (16 mg) and submitted to 1H and 13C Nuclear Magnetic Resonance (NMR) Spectroscopy analysis. The fraction Fr-16-33 was submitted to preparative thin layer chromatography (CCDP), using silica gel 60 as stationary phase and Hex:AcOEt (99:1) as mobile phase, obtaning Vg-2 (12mg). The fraction Fr-41-47 was re-suspended in MeOH, occuring orange solid precipitation and, after filtering, Vg-3 (9mg) was returned. The identification of the obtained fractions was realized by uni- and bidimensional Hydrogen and Carbon 13 NMR Spectroscopy. After spectroscopic analysis, it was possible to distinguish the Vg-1, Vg-2 and Vg-3 fractions as emodin, physcione and chrisophanol antraquinones, respectively, already described in literature but not reported for this seed species yet. This study confirms the V. guianensis chemical characterization, adding to the data of researches previously conducted on different parts of this plant, such as trunk, barks and peels, that have identified, among other substances, the presence of antraquinones, proving that those are the main chemical indicators to this species and, probably, the substances that give to the plant the biological activities described in literature