Chromatographic analysis with different detectors in the
chemical characterisation and dereplication of African propolis
Talanta, 2014 Mar;120:181-90
Propolis or bee glue has very diverse composition and is
potentially a source of biologically active compounds. Comprehensive chemical
profiling was performed on 22 African propolis samples collected from the
sub-Saharan region of Africa by using various hyphenated analytical techniques
including Liquid Chromatography (LC)-UltraViolet Detection (UV)-Evaporative
Light Scattering Detection (ELSD), LC-High Resolution Mass Spectrometry (HRMS),
Gas Chromatography (GC)-MS and LC-Diode Array Detector (DAD)-HRMS/MS.
The diversity of the composition of these African propolis
samples could be observed by heat mapping the LC-UV and ELSD data. The
characteristic chemical components were uncovered by applying Principal
Component Analysis (PCA) to the LC-HRMS data and a preliminary dereplication
was carried out by searching their accurate masses in the Dictionary of Natural
Products (DNP). A further identification was achieved by comparing their GC-MS
or LC-DAD-HRMS/MS spectra with previously published data.
Generally no clear geographic delineation was observed in
the classification of these African propolis samples. Triterpenoids were found
as the major chemical components in more than half of the propolis samples analysed
in this study and some others were classified as temperate and Eastern
Mediterranean type of propolis.
Based on the comparative chemical profiling and
dereplication studies one uncommon propolis from southern Nigeria stood out
from others by presenting prenylated isoflavonoids, which indicated that it was
more like Brazilian red propolis, and more significantly a high abundance of
stilbenoid compounds which could be novel in propolis.
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