Selective analysis of phenolic compounds in propolis by HPLC‐MS/MS

Abstract

Phenolic compounds (flavonoids and phenolic acid derivatives) are major active constituents of the resinous fraction of propolis, and also represent its allergenic principles. We have developed a chromatography electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS/MS) method to characterise the polyphenolic fraction of propolis rapidly and quali-quantitatively. With precursor ion scanning, selective detection of caffeic esters was easily achieved, confirming the identification of prenyl caffeate, benzyl caffeate and phenylethyl caffeate by comparison with synthetic standards. The ionisation and fragmentation behaviour of the major propolis flavonoids was rationalised and applied to selected real samples. Taken together, the results of this study show that the introduction of precursor ion analysis leads to a significant improvement in the characterisation of the phenolic fraction of propolis, paving the way to the establishment of a better quality control for this important natural remedy.

Phenolic characterization of Northeast Portuguese propolis: usual and unusual compounds

“…All the caffeic acid esters had a major fragment at m/z 179, which corresponds to the phenolic acid, and another product ion at m/z 135, resulting from the loss of CO 2 from the phenolic acid. These data are in accordance with the fragmentation pathways reported for caffeic acid esters derivatives [22]. Besides the esters derivatives, a methylated derivative of this phenolic acid, the 3,4-dimethyl-caffeic acid (DMCA), was identified in fraction 6 (ion at m/z 207).…”

“…The structure of other phenolic compounds was also confirmed by the MS/MS data published in the literature, as indicated in Table 1. With respect to these latter compounds, it should be noted that their fragmentation pathways will not be discussed in detail in the present work, as these were previously reported [21][22][23][24]. The chemical structures of these compounds are shown in Fig.…”

“…The chemical composition of European propolis was determined by GC-MS [11,19], LC-MS, and ESI-MS [21][22][23][24]. Also Moreira et al [27] have recently described the phenolic content and the antioxidant potential of Portuguese propolis from two different regions, including the Northeast, but still, their phenolic components were not elucidated.…”

“…A large number of analytical methods have been used for the analysis of phenolic compounds in propolis, including spectrophotometry [17], thin-layer chromatography [18], gas chromatography-mass spectrometry (GC-MS) [19], highperformance liquid chromatography (HPLC) [20], liquid chromatography-mass spectrometry (LC-MS) [21][22][23], electrospray ionization-mass spectrometry (ESI-MS) and electrospray ionization-tandem mass spectrometry (ESI-MS n ) [24], capillary electrophoresis [25], and nuclear magnetic resonance (NMR) [26]. Among these methods, MS with ESI is one of the most-used techniques in the research of natural products, as it is able to analyze complex mixtures because of its high selectivity.…”

Chemical Constituents of Malaysian Apis mellifera Propolis

“…Many studies have analysed the propolis compounds using GC-MS (Murat 2002;Maciejewicz et al 2001;Park et al 2002) and HPLC methods (Osmany et al 2007;Medana et al 2008;Volpi & Bergonzini 2006) since the propolis compounds has varied polarity.…”