Characterization of folic acid, 5-methyltetrahydrofolate and synthetic folinic acid in the high-affinity folate transporters: impact on pregnancy and development

Objectives: Folates are B vitamins that are essential for several molecular, cellular, and biological processes, including nucleotide synthesis, methylation, and methionine cycling. The physiological impacts of these processes on health also extend to cell proliferation, folate deficiency anemia, and reduction of the risk of birth defects during pregnancy. The primary objective of this study was to characterize the binding affinities of different folate forms, folic acid (FA), 5-methyltetrahydrofolate (5MTHF), and folinic acid, to the folate receptors α and β, and to the bovine milk folate binding protein. These three dietary forms of folate are found in enriched grains (FA), various fruits and leafy vegetables (folinic acid), and red blood cells (5MTHF). Methods: The half maximal inhibitory concentration values and binding curves of each of these folates for each receptor were determined. Results: Our results indicated that FA had the highest affinity for all folate receptors, followed by 5MTHF, and lastly, by folinic acid, examined by several orders of magnitudes. Conclusion: These data are expected to provide new insights into the therapeutic applications of the different forms of folate in a variety of diseases.