Several scientific studies have shown that folic acid photodegrades to produce pterin-6-carboxylic acid, 6-formylpterin. 6-hydroxymethylpterin, and 6-methyl pterin. However, the mechanism for the photodegradation of folic acid is not yet known. UV- visible absorption spectra were studied and the molar extinction coefficients were calculated for folic acid, 6-methylpterin, 6-hydroxymethylpterin, 6-formylpterin, and pterin-6-carboxylic acid An effective and efficient separation of the molecules was performed using HPLC.

This work photoirradiated folic acid at 365 nm in neutral PBS and studied the photodegradation process. In the presence of a photoinduced electron acceptor, such as molecular oxygen, the rate of folic acid photodegradation is increased. In the presence of electron donors, such as iodide ion, the rate of folic acid photodegradation is decreased. Based on these observations, we proposed a mechanism which includes formation of reactive intermediates during the photodegradation of folic acid that explains the observed changes in photodegradation reaction rates. This is an important step in understanding the mechanism of photodegradation of this essential vitamin.