[Quality evaluation of ginsenoside reference substances based on qNMR spectroscopy]

Area of Science:

• Analytical Chemistry
• Pharmacognosy
• Spectroscopy

Background:

• Accurate quality evaluation of reference substances is crucial for traditional Chinese medicine (TCM) research and application.
• Existing methods like High-Performance Liquid Chromatography (HPLC) may have limitations in precise quantification.
• Ginsenosides are key active compounds in ginseng, requiring reliable reference standards.

Purpose of the Study:

• To establish and validate a quality evaluation method for ginsenoside reference substances using quantitative nuclear magnetic resonance (qNMR) spectroscopy.
• To compare the qNMR method's results with manufacturer-provided HPLC data for selected ginsenosides.
• To demonstrate the applicability of qNMR for ensuring the quality of TCM reference materials.

Main Methods:

• Proton nuclear magnetic resonance (¹H-NMR) spectra were acquired using a Bruker Avance III 500 MHz spectrometer.
• Dimethyl terephthalate was employed as an internal standard for absolute quantification via the ¹H-qNMR method.
• Linear fitting deconvolution was utilized to enhance the accuracy of peak integration for quantification.

Main Results:

• A validated qNMR spectroscopy-based method was successfully established for ginsenoside quality evaluation.
• The qNMR method was applied to assess the quality of ginsenoside Rg₁, Re, Rb₁, Rd, and notoginsenoside R₁.
• Quantification results from qNMR indicated lower content compared to HPLC normalization methods provided by manufacturers.

Conclusions:

• The qNMR spectroscopy-based method ensures the quality of ginsenoside reference substances.
• This method offers robust support for the accurate quality assessment of TCM and its preparations.
• The qNMR approach is simple, rapid, and accurate, suitable for quantitative analysis of TCM standard references.