Figures and Supporting files.rar

The flavonoids in barley can function in health care and disease treatment, but our knowledge of these chemical compounds is lacking thus far. In the present paper, ultra high-performance liquid chromatography coupled to triple quadrupole mass spectrometry (UPLC-QQQ-MS) and targeted metabolomics were employed, and 244 flavonoids in the mature grains of 8 barley varieties were successfully identified as flavones, flavonols, flavanones, anthocyanins, proanthocyanidins and isoflavones. All 244 components can activate the most of flavonoid synthesis pathways and modification reactions reported in the KEGG database. Additionally, the contents of the 244 flavonoids were significantly different between the mature grains of the 8 barley varieties, and 65 of the 244 flavonoids could not be efficiently detected in the mature grains of some of the varieties. A total of 118 flavonoids showed different accumulation modes in the purple grain varieties than that in the other varieties and can be considered characteristic components of purple barley grain. Barley grain is rich in flavonoids and exhibits many of their metabolic pathways, but the activities of different metabolic proteases can be different between the barley varieties. Thus, selective breeding of purple barley grain varieties may change the accumulation mode of flavonoids in mature barley grains.