Extração verde de compostos bioativos da casca e da polpa do buriti (Mauritia flexuosa L.): avaliação das atividades antioxidante e antibacteriana

Abstract

Buriti (Mauritia flexuosa L.) is a fruit that provides large quantities of bioactive components such as carotenoids and vitamin A. Thus, this species represents a raw material of great potential. In this sense, the objective of the present study was to extract the bioactive compounds from the peel and pulp of the buriti fruit using green solvents to evaluate the antioxidant and antibacterial activities. Initially, extraction of the buriti peel and pulp was performed using deep eutectic solvents (DES), ethanol, and supramolecular solvent (SUPRAS). In addition, the yield of carotenoid extraction with ethanol was evaluated by the conventional and ultrasound-assisted technique. The concentration of total carotenoids in the extracts was evaluated by spectrophotometry, and the concentration of total phenolic compounds and beta-carotene was determined by high-efficiency liquid chromatography (HPLC). The performance of SUPRAS extraction was compared with the results of ethanol extraction using the peel and buriti pulp as matrices. Beta-carotene extraction with SUPRAS yielded 5.82 ± 0.05 mg/g for peel and 26.7 ± 0.02 mg/g for pulp. For total phenolic compounds, yields were 32.1 ± 1.2 µg GAE/g for peel and 24.53 ± 4.9 µg GAE/g for pulp. All extracts presented excellent antioxidant activity, emphasizing the extracts obtained with SUPRAS, which presented EC50 (concentration required to obtain a 50% antioxidant effect) for the sequestration of the ABTS radical of 3.00 µg/mL for the peel and 0.84 µg/mL for the pulp. These extract inhibiting bacterial growth of Staphylococcus aureus (ATCC 29213) and Enterococcus faecalis (ATCC 4028). Moreover, when associated with norfloxacin and gentamicin antibiotics, the extracts showed synergistic action against multiresistant strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. Thus, the extraction of bioactive compounds from buriti using a safe, biocompatible, biodegradable and environmentally friendly solvent such as SUPRAS represents an enormous potential for the development of new pharmaceutical, cosmetic and functional food products.