Phenolic Profiling of Portuguese Propolis by LC-MS Spectrometry: Uncommon Propolis Rich in Flavonoid Glycosides

• Published in: Phytochemical analysis Vol. 24; no. 4; pp. 309 - 318
• Main Authors: Falcão, Soraia I., Vale, Nuno, Gomes, Paula, Domingues, Maria R. M., Freire, Cristina, Cardoso, Susana M., Vilas-Boas, Miguel
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.07.2013; Wiley Subscription Services, Inc
• Subjects: Biomarkers - analysis; Chromatography, Liquid - instrumentation; Chromatography, Liquid - methods; flavonoid glycosides; flavonoids; Flavonoids - analysis; Flavonoids - chemistry; Kaempferols - analysis; Mass spectrometry; Molecular Structure; phenolic compounds; Portugal; propolis; Propolis - analysis; Propolis - chemistry; Spectrometry, Mass, Electrospray Ionization - methods; Portugal
• ISSN: 0958-0344; 1099-1565
• DOI: 10.1002/pca.2412

ABSTRACT Introduction Propolis is a chemically complex resinous substance collected by honeybees (Apis mellifera) from tree buds, comprising plant exudates, secreted substances from bee metabolism, pollen and waxes. Its chemical composition depends strongly on the plant sources available around the beehive, which have a direct impact in the quality and bioactivity of the propolis. Being as Portugal is a country of botanical diversity, the phenolic characterisation of propolis from the different regions is a priority. Objective Extensive characterisation of the phenolic composition of Portuguese propolis from different continental regions and islands. Method Forty propolis ethanolic extracts were analysed extensively by liquid chromatography with diode‐array detection coupled to electrospray ionisation tandem mass spectrometry (LC–DAD–ESI–MSn). Results Seventy‐six polyphenols were detected in the samples and two groups of propolis were established: the common temperate propolis, which contained the typical poplar phenolic compounds such as flavonoids and their methylated/esterified forms, phenylpropanoid acids and their esters, and an uncommon propolis type with an unusual composition in quercetin and kaempferol glycosides – some of them never described in propolis. Conclusion The method allowed the establishment of the phenolic profile of Portuguese propolis from different geographical locations, and the possibility to use some phenolic compounds, such as kaempferol‐dimethylether, as geographical markers. Data suggest that other botanical species in addition to poplar trees can be important sources of resins for Portuguese propolis. Copyright © 2012 John Wiley & Sons, Ltd. The present work establishes a complete phenolic profile of Portuguese propolis from continental regions and islands, by combined liquid chromatography and mass spectrometry (LC/DAD/ESI‐MSn). Seventy‐six polyphenols are described in the study and two groups of propolis were established: the common temperate propolis containing the typical poplar phenolic compounds and an uncommon propolis with an unusual composition in quercetin and kaempferol glycosides ‐ some of them never described in propolis. Data suggest a botanical diversity in the resin sources of Portuguese propolis.