Comparative human in vitro and in vivo bioavailability investigation of bilberry anthocyanins in different complex ligands with different copigmentation status

The colorful anthocyanins are well recognized members of the bioflavonoid phytochemicals. Anthocyanins have gained much attention as the food ingredients with health-promoting functions for recent years. Bilberries have been particularly known as one of the richest sources of anthocyanins. The physiological effects of anthocyanins in humans are dependent on the absorption after ingestion. Clinical studies have demonstrated that the bioavailability of anthocyanins is very low and highly variable because of their instability in physiological absorption conditions. The targets for the development of new anthocyanin products are improved absorption and reduced absorption variability. One way to achieve these targets is an increase of the stability of anthocyanins under physiological conditions. Amongst others, copigmentation of anthocyanins is a natural occurring mechanism to stabilize anthocyanins. For this reason, anthocyanin extracted from bilberry fruits have been investigated for their copigmentation effects in solution. Bilberry Anthocyanin Extracts (BAEs) exerting strong copigmentation effects were tested by both, an in vitro CaCo-2 cell culture system and an in vivo human clinical trial. It could be shown convincingly that copigmentation effects of BAEs were correlated with an increased absorption as well as with reduced absorption variability.