Profiling of polyphenols for in-depth understanding of Tartary buckwheat sprouts: Correlation between cultivars and active components, dynamic changes and the effects of ultraviolet B stress

•Relationship between active compounds and various varieties sprouts.•Forty cultivars of sprouts grown from seeds with different color and shape.•Chemical profiles of flavonoids and anthraquinones.•Appropriate time for harvesting Tartary buckwheat sprouts.•UV-B irradiation for increasing the content of active components. Tartary buckwheat sprouts have a high nutritional value and are gluten-free, and polyphenols are their main active constituents. However, information regarding the active constituents’ difference of Tartary buckwheat sprouts grown from seeds with different morphology, at different developmental stages and environments is limited. Here, we developed a LC–MS-based targeted metabolomics approach to analyze polyphenols (46 flavonoids and 6 anthraquinones) in 40 Tartary buckwheat sprouts varieties. Both flavonoids and anthraquinones contributed to significant differences in sprouts grown from seed with different color or shape. Twenty-seven differential compounds were all at a higher level in 3-day-old sprouts, and the fold change from 3-day-old to 8-day-old sprouts was 1.42–6.64. A total of 25 differential compounds were all significantly upregulated upon UV-B radiation, especially for epicatechin. This study is valuable not only for better breeding cultivars of Tartary buckwheat sprouts, but also assessing their metabolic quality.