Tetrahydrofolic acid properties

The reducing property of ascorbic acid also assists another vitamin, folic acid (Figure 5.18). This is an essential co-factor in various one-carbon transfers for example the methyl group originating from the essential amino acid methionine is required in the formation of a wide variety of compounds including purines, the pyrimidine thymine, the amino acid serine, choline, carnitine, creatine, adrenalin, and many others. In its functional state, folic acid must be in its most reduced tetrahydrofolate form and this is brought about and/or maintained by ascorbic acid. 

Antifolate chemotherapy produced the first cure of a solid tumor, choriocarcinoma. Introduction of high-dose regimens with rescue of host toxicity by the reduced folate, leucovorin (folinic acid, citrovorum factor, 5-formyl tetrahydrofolate, N -formyl FH ), further extended the effectiveness of these drugs to both systemic and CNS lymphomas, osteogenic sarcoma, and leukemias. Most recently, analogs that differ from methotrexate in their transport properties and sites of action have proven useful in treating other cancers. 

Folate-producing Lact. helveticus CD6 isolated from fermented milk was found to produce 5-methyl tetrahydrofolate (5-MeTHF), although it must be stated that the levels of production were not disclosed in the publication (Ahire et al. 2013). This strain was then evaluated for probiotic properties following WHO and FAO guidelines. It showed 90.61% survival at highly acidic conditions (pH 2.0), 90.66% viability in presence of synthetic gastric juice, and 68% survivability at 0.5% bile concentration for 24 h. These properties make this strain an ideal candidate to produce folates directly in the harsh conditions of the GIT. 

---