Urinary Excretion of Anthocyanins Following Consumption of Strawberry and Red Grape Juice.

Abstract

The excretion of anthocyanins in urine following consumption of a mixed juice prepared from strawberry and red grape juice was investigated in a human intervention study. Unmetabolised anthocyanins, and glucuronide derivatives have been detected, with pelargonidin-3 glucoside metabolised into pelargonidin monoglucuronide and pelargonidin-3-glucoside monoglucuronide. The mass of urinary anthocyanins excreted in 24h following consumption of the mixed juice (containing 21.93mg of anthocyanins) was 144nmol consisting of 106nmol of anthocyanins derived from strawberries (0.32% of ingested dose) and 38nmol derived from red grapes (0.22% of ingested dose). A higher proportion of delphinidin-3-glucoside was excreted in the unmetabolised form than less polar anthocyanins (at p≤0.05). Excretion of anthocyanins peaked between 2 and 4h following consumption of the juice. The proportion of the ingested anthocyanins excreted was not significantly different for strawberry and red grape anthocyanins despite the differences in the structures.