Determination of Some Phenolic Acids in Propolis by an HPLC Method

Abstract

The liquid chromatographic method was developed for determination of some organic acid in ethanol and water extracts of propolis from Slovakia. Analysis of chlorogenic acid, p‐hydroxybenzoic acid, and rosmarinic acid was realized with the chromatographic column Symmetry Shield RP18 type and using a gradient of mobile phase methanol‐water (pH=2.5 adjusted with formic acid) and spectrophotometric and fluorescence detection (for p‐hydroxybenzoic acid). Chlorogenic acid in the range from 2.7 to 56.6 µg/g and p‐hydroxybenzoic acid from 3.9 to 150.3 µg/g was determined in tested propolis samples. Rosmarinic acid concentration in all tested propolis samples was below the limit of detection in this method. The significant differences in the acids concentrations were observed for propolis samples from east and west of Slovakia. It is probably the effect of different conditions of the collection of the resin and secrets by bees.

Keywords:

• HPLC
• Propolis
• Chlorogenic acid
• p‐Hydroxybenzoic acid
• Rosmarinic acid

Acknowledgments

The autors gratefully acknowledge the financial support of Grant Agency of Slovak Republic (grants nos. 1/0058/08 and 1/4291/07) and Slovak Research and Development Agency (project no. 20‐035205).