Simultaneous Determination of 10 Flavonoids in Crude and Wine-Processed Radix scutellariae by UHPLC

Radix scutellariae is a well-known traditional Chinese medicine used for the treatments of inflammation, pyrexia, hepatitis, etc. Flavonoids are its main active compounds. The aim of this study is to develop and validate the ultra high-performance liquid chromatography (UHPLC) method for simultaneous determination of 10 flavonoids (baicalin, wogonoside, baicalein, wogonin, oroxylin A, chrysin, scutellarin, oroxylin A-7-O-glucuronide, apigenin and apigenin-7-glucuronide) in crude and wine-processed R. scutellariae. The quantitative determination was conducted by UHPLC. Optimal separation was achieved by gradient elution with mobile phase consisting of 0.01% aqueous formic acid and methanol on a Waters ACQUITY UHPLC BEH C18 column. Detection wavelength was set at 275 nm. Method validation was accomplished with linearity, precision and recovery tests. All calibration curves showed good linearity (R(2) > 0.9993). The limit of detection and limit of quantification of these compounds were from 0.08 to 0.24 µg/mL and from 0.23 to 0.76 µg/mL, respectively. The average recoveries of these compounds were from 96.95 to 109.51% with relative standard deviation (RSD) values from 2.14 to 3.26% for crude R. scutellariae, while from 94.73 to 108.38% with RSD values from 1.83 to 3.47% for wine-processed R. scutellariae. The developed method can be applied to the intrinsic quality control of crude and wine-processed R. scutellariae.