Detecting kinsenoside from Anoectochilus roxburghii by HPLC-ELSD with dual columns of NH₂ and AQ-C₁₈

Kinsenoside is a characteristic component of Anoectochilus roxburghii and accounts for this herb's medicinal and edible values. No international certified standard method is available for kinsenoside analysis as well as extraction and preservation.

To develop a more accurate analytical method of kinsenoside. The effects of extraction and drying methods of A. roxburghii on kinsenoside efficiency were investigated for the first time, as well as to examine the kinsenoside stability.

The amino (NH₂ ) and AQ-C₁₈ columns for detecting kinsenoside extract was systematically compared by high-performance liquid chromatography evaporative light-scattering detector (HPLC-ELSD) and HPLC-diode-array detector (DAD), respectively. Kinsenoside, its epimer goodyeroside A and the degradation product during preservation were identified through HPLC-electrospray ionization mass spectrometry (ESI-MS).

An accurate method of kinsenoside detection by HPLC-ELSD with dual columns of NH₂ and AQ-C₁₈ was established. The ratio of C_{goodyeroside A} to C_kinsenoside (Y) was determined using the AQ-C₁₈ column method. The concentration detected by the NH₂ column was multiplied by 1/(1 + Y) as the corrected result. Using this novel method, the average deviations were reduced by 7.64%. Moreover, the efficiency of kinsenoside extraction with water was almost twice that of extraction with ethanol. Freeze drying also led to a higher extraction efficiency (38.47% increase) than hot-air drying did. Furthermore, the degradation of kinsenoside extract exceeded 70% when stored at 37 °C for 3 months.

This study provides a reliable experimental method and theoretical basis for the quality control of kinsenoside from A. roxburghii, as well as other glycosides.