Simultaneous Determination of Six Flavonoids in Astragali Radix Directional Processed with Four Enzymes by UPLC / 中国实验方剂学杂志

ABSTRACT

Objective:To establish an UPLC method for the simultaneous determination of 6 flavonoids, and to research for the effect of Astragali Radix directional processed with four enzymes (complex enzyme, plant cellulase, snail enzyme, and β-glucosidase) on the contents of flavonoid glycosides and their aglycones in this herb. Method:Chromatographic separation was carried out on ACQUITY UPLC HSS T3 column (2.1 mm×100 mm, 1.8 μm) with the mobile phase of 0.1 mol·L-1 formic acid solution-0.1 mol·L-1 formic acid acetonitrile solution for gradient elution. The detection wavelength was set at 260 nm, the flow rate was 0.3 mL·min-1, the column temperature was 30 ℃, and the injection volume was 2 μL. Result:Calycosin-glucoside, calycosin, ononin, formononetin, 9, 10-dimethoxy-pterocarpan-3-O-β-D-glucoside and 3-hydroxy-9, 10-dimethoxy-pterocarpan showed good linear relationships within their own ranges (R2≥0.998 5), the relative standard deviations (RSDs) of precision, stability and repeatability were all <5.0%, and the average recovery was 97.62%-101.13% with RSDs of 1.4%-2.7%. In 0.5 g·L-1 level of enzyme solution, the contents of calycosin-glucoside, calycosin, ononin, formononetin, 9, 10-dimethoxy-pterocarpan-3-O-β-D-glucoside and 3-hydroxy-9, 10-dimethoxy-pterocarpan in Astragali Radix processed with complex enzyme were 0.082 0, 0.335 9, 0.055 9, 0.104 9, 0.015 0, 0.009 7 mg·g-1, the contents of them in Astragali Radix processed with plant cellulase were 0.105 7, 0.364 2, 0.070 2, 0.117 4, 0.020 8, 0.012 5 mg·g-1, their contents in Astragali Radix processed with snail enzyme were 0.031 4, 0.510 0, 0.043 5, 0.210 9, 0.013 0, 0.013 0 mg·g-1, and their contents in Astragali Radix processed with β-glucosidase were 0.085 3, 0.312 4, 0.061 5, 0.110 8, 0.005 8, 0.009 6 mg·g-1, respectively. Conclusion:After the processing of Astragali Radix by four enzymes, in addition to 9, 10-dimethoxy-pterocarpan-3-O-β-D-glucoside, the contents of calycosin-glucoside and ononin are reduced, but the contents of their three corresponding aglycones are significantly increased. The established method is simple, accurate and reproducible, and is suitable for the simultaneous determination of 6 flavonoids in Astragali Radix, which can provide a reference for this herb directional processed with enzymes.