Liquid chromatography tandem mass spectrometry identification of proanthocyanidins in rat plasma after oral administration of grape seed extract
Abstract
Proanthocyanidin rich plant extracts derived from grape seed extract (GSE), hawthorn and cranberry are on markets for their preventive effects against cardiovascular diseases and uroinfections in woman. However, the importance of these health beneficial effects of these botanicals remains elusive due to incomplete understanding of uptake, metabolism and bioavailability of proanthocyanidins in vivo. In the present study rats were given GSE orally (300mg/kg, twice a day) and blood and urine were collected over a 24h period. Monomeric catechins and their methylated metabolites, and proanthocyanidins up to trimers were detected in blood samples treated with GSE using LC-MS/MS operating in the multiple reaction monitoring (MRM) mode. A new tetramethylated metabolite of dimeric proanthocyanidin (m/z 633) in GSE-treated urine was tentatively identified. Using LC-MS/MS, (+)-catechin and (−)-epicatechin were identified in the brain conclusively. These data suggested that GSE catechins cross the blood brain barrier and may be responsible for the neuroprotective effects of GSE.
aDepartments of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
bDepartment of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
cPurdue-UAB Botanicals Center for Age-Related Disease, University of Alabama at Birmingham, Birmingham, AL 35294, USA
dComprehensive Cancer Center Proteomics/Mass Spectrometry Shared Facility, University of Alabama at Birmingham, Birmingham, AL 35294, USA
eDepartment of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Corresponding author at: Department of Pharmacology & Toxicology, MCLM 456, University of Alabama at Birmingham, 1918 University Boulevard, Birmingham, AL 35294, USA. Tel.: +12059962612; fax: +12059346944.
ABSTRACT