Qualitative Analysis of Polyphenols in Glycerol Plant Extracts Using Untargeted Metabolomics

Area of Science:

• Food Chemistry
• Analytical Chemistry
• Natural Product Chemistry

Background:

• Glycerol is a preferred non-toxic solvent for polyphenol extraction due to high efficiency.
• High glycerol concentrations in plant extracts hinder mass spectrometry analysis (electrospray ionization).

Purpose of the Study:

• To develop a solid phase extraction (SPE) protocol for removing glycerol from plant extracts.
• To enable subsequent polyphenol analysis using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Main Methods:

• Solid phase extraction (SPE) protocol development for glycerol removal.
• Ultra-performance liquid chromatography coupled with quadrupole time of flight tandem mass spectrometry (UPLC-QTOF-MS/MS) for polyphenol analysis.
• Comparison of glycerol and ethanolic extracts from Queen Garnet Plum (Prunus salicina).

Main Results:

• The SPE method successfully removed glycerol, allowing for UPLC-MS/MS analysis.
• Both glycerol and ethanolic extracts of Queen Garnet Plum showed abundant anthocyanins and flavonoids.
• The polyphenol profile revealed 53% glycosides and 47% aglycones; 56% of flavonoids were glycosides and 44% aglycones.
• Two new flavonoid glycosides, Quercetin-3-O-xyloside and Quercetin-3-O-rhamnoside, were putatively identified.

Conclusions:

• A novel SPE method facilitates glycerol removal from plant extracts for mass spectrometry analysis.
• This method expands the analytical capabilities for glycerol-based natural product extracts.
• The study provides new insights into the polyphenol composition of Queen Garnet Plum.