Absorption and metabolism of red orange juice anthocyanins in rats

Anthocyanins are natural pigments that could be involved in various health effects. Red oranges are an important dietary source of anthocyanins, including cyanidin 3-glucoside (Cy 3-glc) and an acylated derivative, cyanidin 3-(6''-malonyl)-glucoside (Cy 3-malglc). The aim of this study was to evaluate the absorption and metabolism of red orange anthocyanins in rats fed an anthocyanin-enriched diet for 12 d (approximately 2.8 micromol anthocyanins/d). Furthermore, the absorption of these anthocyanins was studied in both the stomach and intestine using in situ models in rats. Anthocyanin metabolites were identified and quantified by HPLC-electrospray ionization tandem MS and HPLC-diode array detection, respectively. The red orange anthocyanins, Cy 3-glc and Cy 3-malglc, as well as their respective methylated derivatives, were recovered in urine after red orange juice intake. The 24 h urinary excretion of total anthocyanins was low (0.081 (SEM 0.009) % of the ingested amount). However, a high proportion (about 20 %) of red orange anthocyanins was absorbed from the stomach. More Cy 3-malglc than Cy 3-glc was absorbed in the intestine. This study thus indicated that red orange juice anthocyanins were rapidly absorbed from both stomach and small intestine, and then excreted in the urine as intact and methylated forms. Moreover, the absorption and metabolism of acylated anthocyanins and non-acylated anthocyanins were similar.