ABSTRACT
Vitamin B9 or folate is an essential water-soluble B vitamin that exists in diverse forms (or vitamers). In general, the term folate encompasses both naturally occurring folate and synthetic folic acid. Folic acid or pteroylmonoglutamic acid is the fully oxidized vitamer and it is naturally present in foods at very low concentrations. It does not carry any carbon unit for folate metabolism [1] and is therefore biologically inactive [2]. Nevertheless, folic acid is widely used for the fortication of food and as a dietary supplement, owing to its stability and low manufacturing cost [3,4]. It is readily converted into tetrahydrofolate, the fully reduced form, following absorption [5]. Structurally, folate is composed of three distinct moieties: a heterocyclic pteridine ring, para-aminobenzoic acid, and glutamic acid, as shown in Figure 6.1.
