Antimicrobial and antifungal activities of a coloring extract rich in betacyanins obtained from the flowers of Gomphrena globosa L
Artigo de Conferência
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resumo
There is a huge diversity of pigments from natural origin that can be exploited as colorants in the
food industry. Nonetheless, they can additionally provide several bioactive properties, which
represent an added-value for food products. Carotenoids, chlorophylls, anthocyanins and
betalains are some of the most studied plant-based pigments. Betalains, can be subdivided
according to their chemical structure into betacyanins and betaxanthins [1]. Although less
exploited than Beta vulgaris L., Gomphrena globosa L. is an important source of betacyanins [2],
with antimicrobial and antifungal activity [3]. Thus, the aim of this study was to obtain a pigmented
extract from G. globosa with a high antimicrobial and antifungal activity. This objective was
implemented by the application of the response surface methodology (RSM), a robust
optimization technique that allows to study jointly the effects of several variables and responses,
namely in extraction procedures (in this case ultrasound assisted extraction (UAE)). To evaluate
the antimicrobial and antifungal properties, the responses were the minimum inhibitory (MIC),
minimum bactericidal (MBC) and minimum fungicidal (MFC) concentrations. The optimized UAE
conditions were: 10.8 min, 410.5 W, 57.8% ethanol content (ethanol-water mixtures were used)
and 5 g/L as solid-liquid ratio, providing the following responses: 1) antibacterial activity: MIC of
~0.15-0.35 g/L) and MBC of ~0.30-0.65 g/L; and 2) antifungal activity: MIC of ~0.20-0.30 g/L and
MFC of ~0.40-0.65 g/L. In conclusion, the obtained results evidenced the potential application of
the extracts from G. globosa as sources of betacyanins (natural colorants), but also as important
antimicrobial and antifungal agents.
