|
Notes:
|
Rapid, selective and sensitive methods were developed and validated to determine procyanidins, anthocyanins
and alkaloids in different biological tissues, such as liver, brain, the aorta vein and adipose tissue.
For this purpose, standards of procyanidins (catechin, epicatechin, and dimer B2), anthocyanins (cyanidin-
3-glucoside and malvidin-3-glucoside) and alkaloids (theobromine, caffeine and theophylline) were used.
The methods included the extraction of homogenized tissues by off-line liquid–solid extraction, and then
solid-phase extraction to analyze alkaloids, or microelution solid-phase extraction plate for the analysis
of procyanidins and anthocyanins. The eluted extracts were then analyzed by ultra-performance liquid
chromatography-electrospray ionization-tandem mass spectrometry, using a triple quadrupole as the
analyzer. The optimum extraction solution was water/methanol/phosphoric acid 4% (94/4.5/1.5, v/v/v).
The extraction recoveries were higher than 81% for all the studied compounds in all the tissues, except the
anthocyanins, which were between 50 and 65% in the liver and brain. In order to show the applicability of
the developed methods, different rat tissues were analyzed to determine the procyanidins, anthocyanins
and alkaloids and their generated metabolites. The rats had previously consumed 1 g of a grape pomace
extract (to analyze procyanidins and anthocyanins) or a cocoa extract (to analyze alkaloids) per kilogram
of body weight. Different tissues were extracted 4 h after administration of the respective extracts. The
analysis of the metabolites revealed a hepatic metabolism of procyanidins. The liver was the tissue which
produced a greater accumulation of these metabolites.
This work was supported by the Spanish Ministry of Education and Science financing the project AGL2009-13517-C13-02 and the present work was also supported by the Catalan Government (Interdepartmental Commission for Research and Technological Innovation) through the A. Serra grant. |
