Isolation, Chemical Characterization, and Free Radical Scavenging Activity of Phenolics from Triticum aestivum L. Aerial Parts

Abstract

Fourteen phenolic compounds (flavonoids and phenolic acids) were isolated and 19 were identified in the aerial parts of Triticum aestivum L. The structures of these compounds were established on the basis of the data obtained by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) techniques. T. aestivum L. was found to be rich in flavones, especially in luteolin derivatives. Three of the isolated compounds, including luteolin 6-C-[6Glc″-O-E-caffeoyl-β-D-glucopyranosyl(1″→2)-β-glucopyranoside], luteolin 6-C-[5Rib″-O-E-feruoyl-β-D-ribofuranosyl(1″→2)-β-glucopyranoside], and 3',4',5'-O-trimethyltricetin 7-O-[β-D-glucuropyranosyl(1″→2)-β-D-glucopyranoside], have been reported for the first time in the plant kingdom. The amount of individual phenolics, in winter wheat, was also determined. Additionally, the free radical scavenging potential of the isolated compounds was tested in a simple and rapid thin-layer chromatography-2,2-diphenyl-1-picrylhydrazyl radical test (TLC-DPPH•) with image processing.

Comparison of Flavonoid Profiles in Sprouts of Radiation Breeding Wheat Lines (Triticum aestivum L.)

“…The identification results of the compounds are listed in Table 1. Peaks 1 and 2 show the molecular ions of m/z 579 [M-H]and m/z 563 [M-H] -, respectively, and have retention times higher than that of peak 3 (isoschaftoside), and were reported previously as luteolin 6-C-pentoside 8-C-hexoside and apigenin 6-C-hexoside 8-C-pentoside [25][26][27], respectively; thus, in this study, peaks 1 and 2 were identified as luteolin 6-C-hexoside 8-C-pentoside and apigenin 6-C-hexoside 8-C-pentoside, respectively. Peak 4, appearing between the retention times of peaks 3 (isoschaftoside) and 5 (isoorientin), with a molecular ion of m/z 593 [M-H] -, was identified as apigenin-6,8-di-C-hexoside [27].…”

“…The flavonoids in the 37 wheat sprout samples, including the original cultivar (PL01), certified cultivar ("Geumgang"; PL26), and mutant lines (PL05, PL06, PL08-PL11, PL13-PL20, PL23-PL25, PL41, PL42, PL44, PL46-PL48, and PL50-PL61), were analyzed using HPLC-DAD-ESIMS. Then, 14 peaks in their chromatograms were speculated and identified by comparing their retention time, ultraviolet (UV) spectra, and negative molecular ions with those of the compounds purchased in this study or with those reported previously [24][25][26][27][28]. Peaks 3, 5, and 11 were assigned to isoschaftoside, isoorientin, and isoscoparin, respectively, which were unambiguously identified by comparing the retention times and molecular weights with those of the reference standards.…”

“…Peaks 3, 5, and 11 were assigned to isoschaftoside, isoorientin, and isoscoparin, respectively, which were unambiguously identified by comparing the retention times and molecular weights with those of the reference standards. On the basis of the retention times of peaks 3, 5, and 11, the remaining peaks were tentatively identified by comparing their retention times and the molecular weights of the precursor ion with those reported previously [24][25][26][27][28]. The identification results of the compounds are listed in Table 1.…”

“…The flavonoid profiling of wheat spouts has been studied [24][25][26][27][28], however the variation of flavonoids in the sprouts of the wheat mutant lines according to gamma-irradiated mutation breeding using metabolomics combined with multivariate analysis has not been studied so far. The differences among the samples were difficult to see in the chromatograms; however, the HCA with a heatmap and PCA scores scatter and loading plots showed a clear separation of clusters with the application of a multivariate analysis to the normalized data set.…”

“…Our research group developed novel wheat lines generated by gamma-radiation mutagenesis, exhibiting improved agronomic traits and various phenotypes. Several previous studies have reported the secondary metabolite profiling of T. aestivum, including flavonoids and phenolic acids [24][25][26][27][28], however there have been no studies on the sprouts of gamma-irradiated wheat mutant lines. Thus, the metabolomics for the flavonoid composition of the sprouts of gamma-irradiated mutant lines as well as original and certified cultivars of T. aestivum were investigated by the differences in their chemical composition according to the influence of radiation breeding.…”