Chemical Markers in Italian Propolis: Chrysin, Galangin and CAPE as Indicators of Geographic Origin

Abstract

Knowledge of the chemical composition of propolis is crucial for understanding the characteristics of products of different origins, but also for quality control and regulatory purposes. To date, official monographs or official analyses that allow researchers to evaluate propolis in a proper way have not yet been released. This study focuses on the characterization of twenty-seven Italian propolis samples and the identification of chemical markers that define its geographical provenance. Total polyphenol (TP) and total flavonoid (TF) content, alongside the quantification of pinocembrin, chrysin, galangin, and caffeic acid phenethyl ester (CAPE), were identified as potential markers. Additionally, DPPH assays were conducted to evaluate the antiradical activity of propolis samples. Our findings demonstrated that TPs, TFs and pinocembrin differed in propolis of different origins, especially in samples from the islands. However, the quantification of the sum of chrysin and galangin and CAPE provided a clearer distinction of the geographical origin of the propolis samples. In contrast, the DPPH assay did not prove useful for this purpose, as most results were similar and, therefore, not significant. This study lays the groundwork for future research on propolis. These findings could contribute to the development of more refined methods for distinguishing propolis origins, enhancing the understanding, valuation and quality control of this natural product in various applications.