Inhibition of Folic Acid Uptake by Catechins and Tea Extracts in Caco-2 Cells

In this present study it was aimed to determine whether the catechins contained in green tea and the whole extracts of Camellia sinensis (Theaceae) inhibit the uptake of folic acid by Caco-2 cell monolayers. Our results indicate that (-)-epigallocatechin 3-gallate (EGCG) and (-)-epicatechin 3-gallate (ECG) inhibit cellular folic acid uptake with IC 50 values of 34.8 μmol/L and 30.8 μmol/L, respectively. Furthermore, green and black tea extracts were also found to inhibit folic acid uptake with IC 50 values of approximately 7.5 and 3.6 mg/mL, respectively. According to these results, simultaneous intake of tea and folic acid may inhibit intestinal folic acid absorption. The consequences with respect to the folate status of the body will need to be examined in vivo . Abbreviations EGCG:(-)-epigallocatechin-3-gallate ECG:(-)-epicatechin-3-gallate EGC:(-)-epigallocatechin EC:(-)-epicatechin MTX:methotrexate DHFR:dihydrofolate reductase RFC:reduced folate carrier FRα:folate receptor alpha FRβ:folate receptor beta