Studies on the dynamic accumulations of Sophora alopecuroides L. Alkaloids in different harvest times and the appropriate harvest time

A sensitive and accurate method for the simultaneous determination of five alkaloids, namely 9α-hydroxymatrine (M1), matrine (M2), sophoridine (M3), oxymatrine (M4), alopecurin A (M5) in different parts (seed, legume, stem, and root) and different harvest times of Sophora alopecuroides L. was developed by high performance liquid chromatography (HPLC) with photodiode array detector (PDA) for the first time. The separation by gradient elution was achieved on Scienhome Kromasil C18 (4.6 × 250 mm, 5 μm) column at 30 °C with acetonitrile (A)/0.1% phosphatic acid + 0.1% triethylamine (B) as the mobile phase. The detection wavelength was 205 nm. The optimized method provided a good linear relation (r ≥ 0.9993 for all the target compounds), satisfactory precision (RSD values less than 2.3%) and good recovery (96.4–103.6%). The limits of detection ranged between 0.11 × 10−3 and 4.70 × 10−3 μg for the different analytes. The method was successfully applied to analysis and quality control of alkaloid extracts from the traditional Chinese herbal drugs of S. alopecuroides L.