Ultrahigh-performance liquid chromatography and mass spectrometry (UHPLC-LTQ/Orbitrap/MS/MS) study of phenolic profile of Serbian poplar type propolis.
BACKGROUND
Propolis is a resinous natural substance collected by honeybees from different plant sources. Due to the presence of various phytochemicals, this bee-product exhibits numerous biological activities, including anti-bacterial, anti-viral, anti-inflammatory, anti-oxidant, immunostimulating and anti-tumour effects. As the chemical composition and biological activity of propolis depend on its botanical and geographical origin, searching for new bioactive substances in various types of propolis from unexplored regions is of great importance.


OBJECTIVE
The aim of this study is the evaluation of the phenolic profile of poplar propolis samples in order to characterise Serbian propolis, to identify possible new constituents and to specify the phenolic components relevant for differentiation of poplar propolis samples into two subgroups through simultaneous analysis of poplar bud extracts.


METHODS
Ethanolic extracts of propolis and poplar buds were comprehensively analysed using ultrahigh-performance liquid chromatography coupled with hybrid mass spectrometry, which combines the linear trap quadrupole and Orbitrap MS/MS mass analyser together with chemometric methods.


RESULTS
Extensive fingerprint analysis of Serbian propolis was achieved for the first time. Seventy-five phenolic compounds were detected. Eight of them were identified in propolis for the first time. Pattern-recognition methods applied to the content of ten quantified phenolics verified the existence of two subgroups of propolis, with galangin, chrysin and pinocembrin as the most influential distinguishing factors.


CONCLUSIONS
The phenolic composition of the analysed propolis samples confirm their affiliation to the European poplar type propolis and the existence of two subgroups according to botanical origin.
Innovation Centre of the Faculty of Chemistry Ltd, Studentski trg 12-16, 11000, Belgrade, Serbia.
Petar
P
Ristivojević
Jelena
J
Trifković
Uroš
U
Gašić
Filip
F
Andrić
Nebojša
N
Nedić
Živoslav
Ž
Tešić
Dušanka
D
Milojković-Opsenica
D000818:Animals; D001516:Bees; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D044950:Flavanones / Q000032:analysis* / Q000302:isolation & purification; D005419:Flavonoids / Q000032:analysis* / Q000302:isolation & purification; D010636:Phenols / Q000032:analysis / Q000302:isolation & purification*; D032107:Populus / Q000737:chemistry*; D011429:Propolis / Q000737:chemistry* / Q000302:isolation & purification; D055771:Serbia; D053719:Tandem Mass Spectrometry / Q000379:methods
D044950:Flavanones; D005419:Flavonoids; D010636:Phenols; C037032:galangin; C043561:chrysin; C016063:pinocembrin; D011429:Propolis
Pattern-recognition methods; UHPLC-LTQ/Orbitrap/MS/MS; phenolic profile; poplar type propolis