Busca de fração rica em corante e avaliação das atividades antibacteriana e antioxidante de Renealmia sp.

Abstract

In Brazil, the demand for natural foods is growing, and with it, the search for natural dyes derived from plants. Among the main plant-based dyes are anthocyanins, carotenoids, betalains, chlorophylls, and others. These substances attract attention not only because of their properties as dyes but also because of their potential health effects and benefits. On the other hand, the use of synthetic dyes in food can compromise health, as children may develop various types of allergies or become vulnerable to other diseases. As an alternative, some plants can be used to extract substances for application as natural dyes, such as the fruits of Renealmia sp., which produce purple pigments characteristic of anthocyanins (flavonoids), as well as the peel and pulp, which also have a yellow color with a low presence of carotenoids. Given this problem and the need for new dyes, this project aimed to extract a fraction enriched with natural dye from the fruits of Renealmia sp.. To expand the potential uses, the obtained extracts were evaluated for antioxidant activity (DPPH and Fe3+/phenanthroline) and antibacterial activity (against Staphylococcus aureus ATCC 25923, Streptopcoccus pneumoniae ATCC 49619, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Burkholderia cepacia ATCC 17759, Serratia marcescens ATCC 14756, and Mycobacterium smegmatis). The extracts were fractionated using chromatographic techniques such as flash chromatography for the fractionation of the ethanolic extract of the fruit peels. The extracts were: hydroethanolic extract of the pulp with seeds, methanolic extract of the fruit peels, and hydroethanolic extract of the dried leaves of Renealmia sp. The samples were analyzed using spectroscopic techniques such as UV-Vis and 1H NMR (300 MHz for 1H nuclei) for chemical characterization. The result of the Flash chromatography fractionation of the ethanolic extract of the fruit peels showed fractions affected by substances with antioxidant activity. The hydroethanolic extract of the fruit peels showed moderate activity against the Fe3+/phenanthroline assay. In the antimicrobial assay, the hydroethanolic extract of the pulp with seeds showed activity against Staphylococcus aureus, and the hydroethanolic extract of the dried leaves was also active against Enterococcus faecalis and Mycobacterium smegmatis. The results obtained indicate that the methanolic extract of Renealmia sp. fruit peels shows promise for the removal of dyes, as its fractions contain purple and orange colors. It also exhibits antioxidant and antibacterial activities. The TLC analyses of the methanolic and hydroethanolic extracts were subjected to accusations of containing substances with chromophores. 1H NMR analyses indicate that the methanolic extract of the fruit peels, the hydroethanolic extract of the pulp with seeds, and the hydroethanolic extract of the leaves of Renealmia sp. show signals of sugars and methoxyls, with signals between 3 and 4.5 ppm. However, the hydroethanolic extracts of the leaves and the methanolic extract of the fruit peels show indications of methyl groups, and the hydroethanolic extract of the pulp shows signals of possible flavonoids, with signals between 6.6 and 7.4 ppm. These results encourage further work to isolate the substances present, which may be dyes with antibacterial or antioxidant activity.