Standardizing the analysis of phenolic profile in propolis. (April 2018) - Escriche, Isabel
Abstract: The analysis of propolis is controversial, hampering the comparison of its biological properties and estimation of its commercial value. This work evaluates the effectiveness of combining maceration and ultrasonication extraction techniques on the yield, total phenol content (Folin-Ciocalteau) and the specific phenolic compounds (HPLC-UV), on propolis from different origins. The extraction method was not significant in any case; therefore ultrasonication is recommended (time-saving) but only when a double extraction is performed. Propolis yield varies significantly between samples, as it includes impurities, consequently the results should be expressed considering the yield (as balsam) instead of raw propolis. Of the 13 quantified phenolic compounds, CAPE and pinocembrin (803 and 701 mg/g balsam) stand out. The phenolic profile of a propolis must be fixed using both total phenol content (with a consensus reference compound) and the specific phenolic compounds, since the latter provides information about compounds that can play a significant antioxidant role. Graphical abstract: Unlabelled Image Highlights: A precise standardization of the phenolic profile in propolis is required. Propolis type influences more on the total phenol content than the extraction method. Extraction method affects less than propolis type on the phenolic compounds. Double ultrasonication is the best method for the phenolic extraction in propolis. Total phenol content and phenolic profile define the antioxidant power of propolis.