Analysis of propolis: Some parameters and procedures for chemical quality control

Abstract

A set of parameters and respective procedures for the establishment of chemical profiles of samples of tinctures and crude propolis is presented. It is proposed that estimations of the content of total phenolic substances, flavonoids, waxes, ash, volatile substances and dry residue be used as parameters to characterize samples of crude propolis. For tinctures, the estimations of total phenolic substances, flavonoids, waxes, specific gravity and ethanol are proposed. Total phenolic substances and flavonoids are measured by spectrophotometric methods, waxes gravimetrically and ethanol by gas chromatography. The accuracy of the spectrophotometric procedures was tested by assaying a mixture with a known composition of phenolic acids and flavonoids. The use of the procedures is exemplified by the analyses of six samples of crude propolis from different localities in Brazil and of tinctures prepared with absolute and 70% aqueous ethanol. The contents of total phenolic substances, flavonoids, waxes and volatile compounds of the samples analysed are relatively low in comparison with data from the literature. Samples of propolis from nearby localities may have quite different chemical profiles. Compared with absolute ethanol, extraction with aqueous ethanol results in wax-free tinctures, containing higher amounts of phenolic substances. © 1998 International Bee Research Association.