Transepithelial Transport
of Theasinensins through
Caco‑2 Cell Monolayers and Their Absorption in Sprague–Dawley
Rats after Oral Administration
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Abstract
The aim of this study is to illustrate the <i>in
vivo</i> and <i>in vitro</i> absorption of theasinensins
B and
A that are (−)-epigallocatechin-3-<i>O</i>-gallate
(EGCG)–(−)-epigallocatechin (EGC) dimer and EGCG dimer,
respectively, and their transport pathway across the intestinal membrane.
Our animal study by a single oral administration to rats demonstrated
the intact absorption of theasinensins into the blood system, which
was estimated to be a >10-fold lower absorption amount than EGCG.
The <i>in vitro</i> absorption study indicated that theasinensins
can be transported across Caco-2 cell monolayers, while their permeability
coefficients were also >10-fold lower than those of EGCG and EGC.
Transport experiments using cytochalasin D or quercetin as a tight
junction (TJ) modulator and a non-saturable permeation revealed that
theasinensins were transported across Caco-2 cells in a TJ paracellular
diffusion route. In conclusion, the dimers of condensed catechins,
theasinensins B and A, can be absorbed intact into rat blood and transported
across Caco-2 cell monolayers probably through a TJ paracellular pathway