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 +/- 1.25 nm after preparation. The TP nanoemulsion was stable during storage at 4, 25 or 40 degrees C for 20 days. 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 (C-max) of EGCG and EGC, but the area under the plasma concentration-time curve (AUC(0-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.