Investigation of the Hydrolysis of Ginsenosides by High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry

Abstract

The hydrolysis of ginsenoside standards and the crude extracts of ginseng has been investigated at different pH values (2.4 - 11.2) using high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). The experimental results indicated that the pH value of aqueous solutions is an important factor in changing the composition of ginsenosides. For (20S)-protopanaxadiol ginsenosides, ginsenosides with a large mass hydrolyzed to form hydrolysates (20S)-Rg₃ and (20R)-Rg₃ at pH 4.3. There were more hydrolyzed products observed at pH 3.3: (20S)-F₂, C-25,26 hydrated ginsenoside ”C-Y₁” and ”C-Y₂” (MW = 802 Da) accompanied with (20S)-Rg₃, (20R)-Rg₃. At pH 2.4, only (20R)-Rg₃, (20S)-F₂, a small quantity of (20S)-Rg₃ and three C-25,26 hydrated ginsenosides were obtained. For (20S)-protopanaxatriol Re, no hydrolysates were observed at pH 4.3; it was hydrolyzed at pH 3.3 to form hydrolysates (20S)-Rg₂, (20R)-Rg₂ and hydrated C-25,26 (MW = 802 Da) and at pH 2.4 only C-25,26 hydrated ginsenosides ”C-Y₁” and ”C-Y₂” (MW = 802 Da) were left in the solution. Similar hydrolysis reactions could be also observed for the crude extracts of ginseng. It showed that HPLC/ESI-MS is a fast and convenient method to study the hydrolysis of ginseng.

Hydrolysis - ginseng - Panax ginseng - Panax quinquefolius - Araliaceae - ginsenoside - HPLC-ESI-MS

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