Nanoemulsion delivery system of tea polyphenols enhanced the bioavailability of catechins in rats

Tea polyphenols (TP) were emulsified with corn oil and polysorbate 80 by high-pressure homogenization. The oil in water (O/W) TP nanoemulsion had droplet sizes of 99.42±1.25nm after preparation. The TP nanoemulsion was stable during storage at 4, 25 or 40°C for 20days. An in vitro simulated digestion assay showed that the bioaccessibility of (-)-epigallocatechin gallate (EGCG) was increased in the nanoemulsion compared to that in aqueous solution, but that the bioaccessibilities of (-)-epigallocatechin (EGC), (-)-epicatechin (EC) and (-)-gallocatechin gallate (GCG) were greatly decreased. Compared with rats fed an aqueous TP solution, rats fed the TP nanoemulsion had significantly lower maximum plasma concentrations (Cmax) of EGCG and EGC, but the area under the plasma concentration-time curve (AUC0-t) was increased. The data show that use of a nanoemulsion system to deliver tea polyphenols may enhance the absorption of EGCG through controlled release.