Triple aldose reductase/α-glucosidase/radical scavenging high-resolution profiling combined with high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy foridentification of antidiabetic constituents in crude extract of radix scutellariae

In this work, development of a new microplate-based high-resolution profiling assay using recom-binant human aldose reductase is presented. Used together with high-resolution radical scavengingand high-resolution α-glucosidase assays, it provided the first report of a triple aldose reductase/α-glucosidase/radical scavenging high-resolution inhibition profile - allowing proof of concept with RadixScutellariae crude extract as a polypharmacological herbal drug. The triple bioactivity high-resolutionprofiles were used to pinpoint bioactive compounds, and subsequent structure elucidation was performedwith hyphenated high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy. The only α-glucosidase inhibitor wasbaicalein, whereas main aldose reductase inhibitors in the crude extract were baicalein and skull-capflavone II, and main radical scavengers were ganhuangemin, viscidulin III, baicalin, oroxylin A7-O-glucuronide, wogonoside, baicalein, wogonin, and skullcapflavone II. © 2015 Elsevier B.V.