Targeted metabolomic study to discrimínate Argentinean wheat varieties

BARONI, MARÍA V.; PODIO, NATALIA S.; WUNDERLIN, DANIEL A.

Rosario

Congreso; 2nd Latin American Metabolic Profiling Symposium (II LAMPAS); 2016

Bolsa de Comercio de Rosario

Targeted metabolomics are important for assessing the behavior of a specific group of compounds in the sample under determined conditions. In this context, the study of polyphenols has gained much attention because they have the ability to prevent oxidative stress. The aim of this study was to evaluate the polyphenol profile of 12 Argentinean wheat varieties (ACA 303, ACA 315, ACA 320, ACA 903 B, BAGUETTE PREMIUM 11, BIOINTA 3004, BUCK 75 ANIVERSARIO, CRONOX, KLEIN CAPRICORNIO, KLEIN GUERRERO KLEIN YARARÁ and LE 2330) from different regions in 2 seeding years. Polyphenol extraction was performed in two fractions (free fraction-FF and bound fraction-BF) and the polyphenol profile was studied by HPLC-DAD-ESI-QTOF. Twenty-five compounds were identified in wheat extracts: 11 of them were identified in the FF, while 14 compounds were identified in the BF. Three hydroxybenzoic acid derivative compounds, tryptophan (included because it contributes to the total polyphenol values), 3 flavones, p-coumaroyl-feruloylputrescine, trans-ferulic acid and 3 dimers of ferulic acid (isomers 3, 4 and 6) were found in FF of wheat extracts. The most abundant compound in this fraction was hydroxybenzoic acid glucoside and BUCK 75 ANIVERSARIO variety showed significantly highest values (P < 0.05) of this compound, while the other varieties did not show significant differences between them. With respect to the BF of wheat extracts, p-coumaric acid; trans-ferulic acid; cis-ferulic acid and 8 dimers and 1 trimer of ferulic acid (DFAs and TFA, respectively) were identified. The main compound quantificated in BF was trans-ferulic acid, followed by isomer 9 of DFA. Both compounds showed significant differences (P < 0.05) between wheat varieties. To assess whether the profile of polyphenols is able to differentiate between varieties of wheat, principal component analysis (PCA) was applied taking into account the 25 compounds identified. PCA model was obtained using four principal components (PCs), which explained 84% of the variability found in the analyzed data. PC 1 explained 49.4% of the variability found among different wheat varieties studied, while CP 2 explained 14.5% of it. DFAs from BF were the largest contributors to the CP1 allowing differentiate both ACA 315 and KLEIN CAPRICORNIO varieties from both LE 2330 and BIOINTA 3004 varieties. Furthermore, 2-hydroxy-3-O-β-D-glucopyranosylbenzoic acid, followed by compounds ferulic acid derivative, p-coumaroyl-feruloylputrescine, hydroxybenzoic acid glucoside, 6-C-glucosyl-8-C-arabinosyl-apigenin, trans-ferulic acid, cis-ferulic acid and chrysoeriol-6,8-di-C-pentoside explained the variability found in the PC 2, which allowed separate BAGUETTE PREMIUM 11 variety from CRONOX. This analysis shows that the polyphenol profile depends of the wheat variety studied, being the ferulic acid derivatives (DFAs, cis and trans-ferulic acids), hydroxybenzoic acids (2-hydroxy-3-O-β-D-glucopyranosylbenzoic acid and hydroxybenzoic acid glucoside) and flavones (chrysoeriol-6,8-di-C-pentoside and 6-C-glucosyl-8-C-arabinosyl-apigenin) the most important compounds for their differentiation.