Abstract:Flavonoid extracts from black Tartary buckwheat contain numerous impurities, and their composition and activities require further investigation. Black Tartary buckwheat bran was used as the raw material. The flavonoid extract was purified using macroporous resin, and the resin type was screened based on adsorption and desorption rates. The flavonoid composition was analyzed by ultra-high performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). The total reducing power, DPPH and ABTS radical scavenging capacities were determined, and the synergistic antioxidant effect of rutin and flavonoid mixtures was investigated. The antibacterial activity was evaluated by broth microdilution and Oxford cup methods. The results showed that the adsorption and desorption rates of AB-8 macroporous resin were 47.74% and 86.90%, respectively, which were higher than those of other resins. A total of 15 flavonoids were identified, among which the relative contents of quinic acid, rutin and nicotine were 61.81%, 18.22% and 6.60%, respectively. The antioxidant capacity of the purified flavonoids was higher than that before purification, and the synergistic antioxidant effect was strongest when rutin and flavonoids were mixed at a ratio of 1:1. The MIC of black Tartary buckwheat flavonoids against Staphylococcus aureus was 17.95 μg/mL, and the MICs against Escherichia coli and Pseudomonas aeruginosa were both 35.9 μg/mL. These results provide a reference for the purification and functional activity studies of black Tartary buckwheat flavonoids.