Determination of Tetrandrine, Fangchinoline, Cyclanoline and Oblongine in Radix Stephaniae Tetrandrae by High-Performance Liquid Chromatography

A reversed-phase high-performance liquid chromatographic method to simultaneously measure the four alkaloids [tetrandrine, fangchinoline, cyclanoline and oblongine] in Radix Stephaniae tetrandrae has been successfully developed. The method uses standards of the four compounds as external standards. These compounds were isolated in our laboratory using various chromatographic methods and are completely separated within 45 min using a reversed-phase column and linear gradient elution with dihydrogenphosphate buffer HPLC-grade acetonitrile mobile phase. The quantitative calibration curves are linear over a range of 12.5-1637 ig/ml for all four compounds. The detection limits (S/N=3) for tetrandrine, fangchinoline, cyclanoline and oblongine are approximately 0.95, 0.95, 0.95 and 1.69ig/ml, respectively.