Absorption, tissue distribution and excretion of pelargonidin and its metabolites following oral administration to rats

Abstract

Recent reports have demonstrated various cardiovascular and neurological benefits associated with the consumption of foods rich in anthocyanidins. However, information regarding absorption, metabolism, and especially, tissue distribution are only beginning to accumulate. In the present study, we investigated the occurrence and the kinetics of various circulating pelargonidin metabolites, and we aimed at providing initial information with regard to tissue distribution. Based on HPLC and LC-MS analyses we demonstrate that pelargonidin is absorbed and present in plasma following oral gavage to rats. In addition, the main structurally related pelargonidin metabolite identified in plasma and urine was pelargonidin glucuronide. Furthermore,p-hydroxybenzoic acid, a ring fission product of pelargonidin, was detected in plasma and urine samples obtained at 2 and 18h after ingestion. At 2h post-gavage, pelargonidin glucuronide was the major metabolite detected in kidney and liver, with levels reaching 0·5 and 0·15nmol pelargonidin equivalents/g tissue, respectively. Brain and lung tissues contained detectable levels of the aglycone, with the glucuronide also present in the lungs. Other tissues, including spleen and heart, did not contain detectable levels of pelargonidin or ensuing metabolites. At 18h post-gavage, tissue analyses did not reveal detectable levels of the aglycone nor of pelargonidin glucuronides. Taken together, our results demonstrate that the overall uptake of the administered pelargonidin was 18% after 2h, with the majority of the detected levels located in the stomach. However, the amounts recovered dropped to 1·2% only 18h post-gavage, with the urine and faecal content constituting almost 90% of the total recovered pelargonidin.