Quality Evaluation of Andrographis paniculata Capsules Based on Rapid and Accurate LC-ESI-MS/MS Assay of Three Diterpenoids.

Andrographis paniculata is an important traditional Chinese herbal material widely used for treatment of fever and diarrhea. The three diterpenoids [andrographolide (AP), dehydroandrographolide (DP) and neoandrographolide (NP)] in A. paniculata were characterized as the key active components for its extractive and related medicinal preparations. A rapid and accurate quantitative analysis of these three diterpenoids in A. paniculata capsules was accomplished by means of a valid and reliable high-performance liquid chromatography with tandem mass spectrometric (HPLC-MS/MS) analytical method. An optimized gradient elution method, which under the mobile phase consisting of methanol and water, was established successfully. An XDB C18 column (3.5 μm, 2.1 mm × 50 mm) was successfully applied to separate these three diterpenoids at the flow rate of 0.55 mL/min. A triple quadrupole mass spectrometer with multiple reaction monitoring (MRM) mode using an electrospray ionization source was served for analytical detection. The linearity, specificity, accuracy, recovery, precision, stability and repeatability were demonstrated to fully confirm the validity of this study. Good linear regression relationships for the three analytes were obtained over the range of 0.50-1000 ng/mL. Intra-day and inter-day precisions were evaluated with relative standard deviation < 7.62%, and the extraction recovery varied from 93.8% to 102.0%. The rapid and accurate HPLC-MS/MS analytical method was developed for the quality evaluation of A. paniculata capsules successfully. The content of AP, DP and NP obtained were 3.90-4.08, 4.77-5.04, 4.32-4.48 mg/g in A. paniculata capsules, respectively. Moreover, it is expected that this analytical technique can be applied to detect three effective components rapidly and accurately in other different medicinal preparations of A. paniculata as a method for their quality control.