Absorption Of Epigallocatechin Gallate Research Articles

The Loading of Epigallocatechin Gallate on Bovine Serum Albumin and Pullulan-Based Nanoparticles as Effective Antioxidant.

Due to its poor stability and rapid metabolism, the biological activity and absorption of epigallocatechin gallate (EGCG) is limited. In this work, EGCG-loaded bovine serum albumin (BSA)/pullulan (PUL) nanoparticles (BPENs) were successfully fabricated via self-assembly. This assembly was driven by hydrogen bonding, which provided the desired EGCG loading efficiency, high stability, and a strong antioxidant capacity. The encapsulation efficiency of the BPENs was above 99.0%. BPENs have high antioxidant activity in vitro, and, in this study, their antioxidant capacity increased with an increase in the EGCG concentration. The in vitro release assays showed that the BPENs were released continuously over 6 h. The Fourier transform infrared spectra (FTIR) analysis indicated the presence of hydrogen bonding, hydrophobic interactions, and electrostatic interactions, which were the driving forces for the formation of the EGCG carrier nanoparticles. Furthermore, the transmission electron microscope (TEM) images demonstrated that the BSA/PUL-based nanoparticles (BPNs) and BPENs both exhibited regular spherical particles. In conclusion, BPENs are good delivery carriers for enhancing the stability and antioxidant activity of EGCG.

Identification of the Catechin Uptake Transporter Responsible for Intestinal Absorption of Epigallocatechin Gallate in Mice

Many studies have shown that epigallocatechin gallate (EGCg) contribute to the health benefits of green tea, although its bioavailability is usually low. However, the mechanism underlying its intestinal absorption remains unclear. In human subjects, it has been reported that the bioavailability of EGCg increases after repeated oral catechin intake. We hypothesized that a certain uptake transporter was involved in this increase, and investigated a novel EGCg transporter. We first confirmed the increase in EGCg bioavailability in mice fed the catechin diet for two weeks. Then, in situ intestinal catechin infusion exhibited that the absorption of EGCg in the ileum was selectively increased in mice fed the catechin diet. A comprehensive analysis of plasma membrane proteins revealed 10 candidates for EGCg transporter, which were selectively increased in the ileum. EGCg uptake by a Xenopus laevis oocyte expressed with respective transporter revealed that oocytes microinjected with DTDST cRNA exhibited significantly higher EGCg uptake. Furthermore, uptake of EGCg by CHO-K1 cells stably expressing DTDST was significantly higher than that by mock cells, which was nullified by treating with a DTDST inhibitor. In conclusion, this study identified DTDST as a novel intestinal EGCg transporter that is upregulated after repeated oral catechin intake.