Otimização do processo de purificação da R-Ficoeritrina da macroalga marinha vermelha Solieria filiformis e determinação da sua capacidade antioxidante

Abstract

R-Phycoerythrin (R-PE) is a photosynthetic pigment (phycobiliprotein) present in red macroalgae, which has been applied as a fluorescent probe in cytometry, microscopy, immunochemistry and has been presented important biological activities for human health such as antioxidant, antitumor and anti-inflammatory. R-PE also has application as a food colorant and in pharmacological and cosmetic products. However, the yield of the extraction methods as well as the purification of this macroalgal pigment is still low. Thus, the present work aimed to optimize the R-PE purification process of the red marine macroalgae Solieria filiformis, in order to increase the yield of the pure pigment, and to determine its antioxidant activity. For that, a continuous 6-hour extraction was carried out in 25 mM potassium phosphate buffer (PB), pH 6.5, after grinding in an electric mill for three minutes. Then, the crude extract of S. filiformis was subjected to ion exchange chromatography on a DEAE-Sephacel matrix. Thereafter, in order to increase the purity index of the pigment, a 100 kDa membrane Vivaspin ultrafiltration was performed. The pigment obtained after the ultrafiltration process was used to carry out the antioxidant activity tests, using three methods. The chromatographic peak reached a yield of 0.11 ± 0.008 mg of R-PE / g of wet algae and recovery of 62.32 ± 2.23%, value up to three times higher than that reached in works that used the same macroalgae for obtaining R-PE. After the ultrafiltration, the retained material achieved a recovery of 37.69 ± 1.267%, a value about 12% lower than that reported in the literature, but reached a higher purity index of 2.36 ± 0.146. The pure R-PE reached a high antioxidant capacity in the three tested methods, reaching a concentration of 500 μg / mL, ferrous ion chelating capacity of 94.75 ± 1.86%, sequestration of the DPPH radical in 79.04 ± 0, 66% and the ABTS radical, 97.98 ± 0.52%. In view of the obtained results, it was possible to conclude that the purification process was optimized, achieving a yield, recovery and purity index higher than those reported in the literature, generating a faster and more efficient purification scheme. In addition, the antioxidant activity of this phycoerythrin was shown to be elevated by three methods tested.