Background: Traditional Chinese medicine (TCM) preparations are very complex mixtures, and the content of bioactive components is usually very low. Therefore, before final analysis, the preparation of an appropriate sample is necessary. Sample preparation is the most time-consuming and error-prone part of the analytical procedure, and the choice of purification technology greatly influences the reliability of the final analysis.
Methods: In the present study, we evaluated the feasibility of hollow fiber centrifugal ultrafiltrate (HFCF-UF) as a purification technology for the analysis of bioactive components in TCM preparations. The HFCF-UF technology was applied to analyze honokiol and magnolol in TCM preparations containing Cortex Magnoliae Officinalis (Hou Po in Chinese Pinyin). A mini centrifugal device based on hollow fiber was employed to remove the macromolecule components. A single step of simple centrifugation was required before the filtrate could be directly injected into an existing high performance liquid chromatography (HPLC) system without any further clean-up step or use of special columns. This greatly simplified the pretreatment steps, and improved the accuracy of analytic methods. The separation was achieved on a Diamonsil C18 column (i.d. 5 µm, 150 mm × 4.6 mm) with V (methanol):V (acetonitrile):V (0.5% acetic acid solution) =44:22:34 as the mobile phase at a flow rate of 1.0 mL/min.
Results: It had good linear relationship between the peak areas of honokiol and magnolol and their concentrations at 6.40-205 and 3.15-101 µg/mL (r=0.9999), respectively. The method recovery was over 92.6% with a relative standard deviation (RSD) of less than 3.0%. The average recovery of honokiol was 97.7% with an RSD of 3.0%, and that of magnolol was 96.8% with RSD of 2.8%.
Conclusions: The application of HFCF-UF in TCM preparations could assist in making the quality control of TCM simple, rapid, and accurate. The HFCF-UF purification procedure can be used as an alternative means for analyzing bioactive components in TCM preparations.
Keywords: Liquid chromatography; hollow fiber centrifugal ultrafiltrate (HFCF-UF); honokiol; magnolol; purification technology; traditional Chinese medicine (TCM).