Caracterización de compuestos antioxidantes carotenoides y polifenoles presentes en las microalgas Chlorella sp. y Nannochloropsis oculata cultivadas in vitro con potencial nutricional

Abstract

Microalgae are an excellent source for the research and production of bioactive compounds. In this work, the antioxidant capacity of different extraction solvents in Chlorella was evaluated, and carotenoids and polyphenols were characterized in Chlorella sp. and Nannochloropsis oculata. Therefore, a methodology that includes optimized culture of microalgae, genetic identification with molecular biology tools, extraction with maceration and ultrasonication by hydrophilic solvents: ethanol/water 50:50 and 95:5 (v/v), and lipophilic solvents: dichloromethane and n-hexane, comparison of the antioxidant activity of the extracts obtained by the methods of capture of the free radical 2,2-diphenyl-1-picrylhydracil (DPPH), reducing power and the β-carotene bleaching, and chemical characterization in both microalgae by RP-HPLC-DAD, was used to relate its antioxidant activity with its chemical profile. The polar and apolar solvents most efficient in antioxidant activity in Chlorella were applied to N. oculata. It was perceived that the use of enriched cultures generated high concentrations of antioxidants. The molecular evaluation revealed similarity for Chlorella spp. with the ITS sequence. The results showed that the ethanol/water 95:5 and dichloromethane solvents provided the highest antioxidant activity in all the tests, which explains why the extracted compounds have multiple antioxidant mechanisms. Important concentrations of carotenoids (lutein, α- and β-carotene) and a phenolic compound (luteolina) were found in Chlorella sp. In contrast, in N. oculata, an important concentration of the carotenoid fucoxanthin. Apparently, the carotenoids found in Chlorella could explain the high observed antioxidant activity. The high production of lutein, especially, makes it a source with great nutritional potential.