Rapid and comprehensive profiling of α-glucosidase inhibitors in Buddleja Flos by ultrafiltration HPLC–QTOF-MS/MS with diagnostic ions filtering strategy

Abstract Buddleja Flos is used as yellow rice colorant and a well-known traditional Chinese medicine. But its biochemical profiling is still lack due to complex matrix. Here, ultrafiltration high-performance liquid chromatograph–quadrupole time-of-flight tandem mass spectrometry (HPLC–QTOF-MS/MS) with diagnostic ions filtering strategy was proposed for rapid and comprehensive investigation of its α-glucosidase inhibitors. As a result, 33 bioactive compounds (13 phenylethanoid glycosides and 20 flavonoids) were successfully screened and identified. In addition, α-glucosidase inhibitory activities of twenty-two references were verified. Six flavonoid aglycones (4, 28, and 30–33) showed excellent α-glucosidase inhibitory activities (IC50, from 5.11 ± 0.85 to 32.49 ± 9.76 μg/mL), much higher than that of acarbose (IC50, 195.49 ± 10.05 μg/mL). Five flavonoid-monoglycosides (7, 12, 13, 20, and 22) presented moderate inhibitory activities with IC50 from 160.98 ± 23.19 to 249.37 ± 35.83 μg/mL. Results showcased the high efficiency of proposed strategy in profiling of bioactive compounds from natural products.