Identification of bioactive compounds in quinoa seeds following a metabolomics approach

Abstract

Many studies reveal that the intake of food with a high content of bioactive compounds provides physiological benefits to consumers. Quinoa (Chenopodium quinoa Willd.) has been the subject of many of these recent studies, since it has been progressively introduced in Western countries, where it is sold as a protein-rich and gluten-free food, which means an excellent alternative for people with celiac disease. In this work, an untargeted metabolomics approach based on liquid chromatography-mass spectrometry (LC-MS) was applied for the identification of low molecular mass bioactive compounds in six colored quinoa seed accessions from different regions of Peru (two white (W), two grey (G), and two pink (P)). After an exhaustive literature search, the creation of an extensive database, and the application of a suitable LC-MS workflow, 111 low molecular mass bioactive compounds were identified (considering all the quinoa accessions). Most of these bioactive compounds belonged to the family of saponins, a type of terpenoids, which possess antioxidant and anticancer activity, among other physiological bioactivities. Flavonoids, phenolic acids, and organic acids were also identified. In order to find metabolomic differences between the accessions, the areas of the low molecular mass bioactive compounds identified in the quinoa accessions were considered for multivariate data analysis using principal component analysis, PCA, followed by partial least squares-discriminant analysis, PLS-DA. After that, a total of 73 out of the 111 identified bioactive compounds were found to be important for discriminating between W, G, and P accessions, 32 of them belonging to the family of saponins.