THE BIOACCESSIBILITY AND BIOAVAILABILITY OF EGCG IN COMPLEXES WITH β-LACTOGLOBULIN

The green tea catechin (-)-epigallocatechin-3-gallate (EGCG) has attracted significant research interest due to its beneficial health effects, including, anti-oxidant, neuro-protective and anti-cancer effects. However, the therapeutic potential of EGCG following oral consumption is limited by its poor bioavailability and oxidation sensitivity, mainly at natural pH. Our research group has recently introduced a novel technology for nanocomplexation of such potentially beneficial molecules, using heat-denatured β-Lactoglobulin (β-Lg). These nanocomplexes were found to protect EGCG during shelf life, and to mask its bitterness and astringency. In the current research we study the bioaccessibility and the antioxidative activity of free EGCG and of EGCG complexed with β-Lg during simulated gastrointestinal (GI) digestion. Moreover, we evaluate the in vivo bioavailability of free EGCG vs. EGCG complexed with β-Lg in a rat study. We hypothesized that the nanocomplexation of EGCG with β-Lg may protect EGCG from deterioration and improve its bioavailability.

Preliminary results obtained showed that for the EGCG–β-Lg system the overall concentration of bioaccessible EGCG increases during GI digestion, due to the protection conferred to EGCG by β-Lg against deterioration on one hand and the release of EGCG during intestinal digestion on the other. In contrast, during GI digestion of EGCG alone it deteriorated mainly during the duodenal digestion phase, as it is more sensitive at the higher pH of the small intestine. The rat study showed that the administration of EGCG–β-Lg nanocomplexes significantly enhanced the bioavailability of EGCG relative to that of free EGCG in solution.

The results of the proposed project are expected to facilitate enrichment of foods and beverages with protected EGCG and consequently making it more available and bioavailable.