Extração pressurizada de ficobiliproteínas da microalga Arthrospira platensis e avaliação da sua atividade antioxidante e citotoxicidade in vitro em linhagens cancerígenas

Abstract

Microalgae are considered a potential sustainable raw material for the production of biochemically active compounds such as phycobiliproteins. Phycobiliproteins are a group of chromoproteins present in cyanobacteria such as blue-green and red algae. Commercially, phycobiliproteins are natural products of high value with biotechnological applications, for example, nutraceuticals, and pharmaceuticals, in the food and cosmetics industries, as well as in biomedical research and clinical diagnostics. The use of phycobiliproteins as natural non-toxic and non-cancerous dyes is gaining importance worldwide due to the potential for toxicity and carcinogenicity of synthetic food dyes. To obtain phycobiliproteins, an efficient extraction method must be selected than allows obtain high values of extraction yield and purity index. In this context, the objective of the present study was to evaluate the pressurized extraction method, applying different conditions, to obtain phycobiliproteins from microalgae Spirulina (Arthrospira platensis), using sodium phosphate buffer as the extraction solvent. Phycobiliproteins extracts were characterized and their antioxidant and cytotoxicity potential was determined. The increase in pressure favored the increase of the extraction yield and did not influence the biofunctionality of the extracted molecules. The results showed that the extraction method is very promising, mainly for the extraction of phycocyanin and allophycocyanin, obtaining concentrations of 4.44 g.L-1 and 1.63 g.L-1 after 360 min, respectively, in the process conducted at 100 bar. The extract obtained at this pressure showed a high purity index, 3.59 for phycocyanin and 1.72 for allophycocyanin, and with an extraction yield of 44.44 mg.g-1 and 16.33 mg.g-1, respectively. After the purification process by ion exchange chromatography in DEAE sepharose, with only one step, was obtained an extract rich in phycocyanin with a purity of 4.76 and 2.19 for allophychocyanin. Besides, the purified phycobiliprotein extract showed high antioxidant activity, with 98% in the reduction of DPPH radicals and 100% in the chelation of ferrous ions, as well as showing an anti-cancer activity in in vitro tests for HL60 leukemic cells. Thus, the pressurized extraction method is efficient for obtaining phycobiliproteins without damaging their biofunctionality using non-toxic solvent, being an environmentally friendly process.