Frutos não convencionais amazônicos: descrição química e propriedades antioxidantes e antiglicantes

Abstract

The fruits from the species of Psidium, Eugenia and Myrcia have demonstrated economic importance for Brasil and mainly for Amazon region. In this work, the chemical study of the unconventional Amazon fruits from three Psidium spp., five Myrcia spp. and Eugenia punicifolia was performed using a non-invasive methodological approach, trend on chromatographic and spectrometric methods (NMR, DI-ESI-IT-MS/MS and HPLC-DAD-MS) assisted by chemometric tools. In addition, the antioxidant and antiglycant properties of these fruits were determined. This study has allowed the identification of O-glycosyl flavonoids (quercitrin, myricitrin and astilbin), triterpenes (2α-hydroxyfluidic acid, guavenoic, guajavanoic, and madecassic), phenolic acids (derived from gallic, ellagic and cinnamic acids), ellagitannins (pedunculagine) and other acids (citric, malic, shiquimic, and quinic), as well as fatty acids (linoleic, linolenic and palmitic). The content of L-(+)-ascorbic acid was quantified by HPLC-DAD in these fresh fruits, as well as the levels of quercitrin, ellagic and gallic acids by NMR (ERETIC2). The methanolic extracts of E. punicifolia pulps, M. bracteata seeds, green whole fruits of M. minutiflora and green pulps and seeds of M. fenestrata showed better antiglycant and antioxidant response. The chemometric analyzes (PCA and HCA) have demonstrated that the chemical composition has varied qualitatively and quantitatively in the different phenological stages of these fruits. PLS analysis has shown that the ellagitannins and the glycosylated flavonoids present in these fruits are correlated with the antiglycant responses. In addition, the cinnamic acid derivatives have shown strongly associated with the antioxidant response. Thus, the chemometric study allowed associating the response of the antioxidant and antiglycant potentials to the chemical constituents present in these matrices. Therefore, this chemical study demonstrated the nutritional importance of these amazonian fruits due to the presence of bioactive compounds that can act as natural antioxidants and serve to prevent certain diseases, specially related to cellular oxidative processes such as cancers and diabetes. These results motivated the encapsulation of E. punicifolia fruit juice, which efficiencies of encapsulation and retention are promising for amazonian bioproducts.