Bisdehydroascorbic acid

The fact that DHA possesses vitamin C activity was recognized early in studies of AA and was studied by several groups (13,14), Enzymes that catalyze the reduction of DHA to AA have been demonstrated in many systems and are discussed later in this chapter. Dimeric DHA, or bisdehydroascorbic acid (BDHA), and DHA both are important in nutrition this importance has been taken for granted in that the common assay of ascorbic acid, the dinitrophenylhydrazine (DNPH) method, does not distinguish between these forms. 

The development of a satisfactory DHA synthesis has been hampered by the problems of over-oxidation and also by the limited stability of DHA in aqueous solution. T o date, DHA has been obtained only as a viscous syrup or amorphous solid. A convenient preparative method involves oxidation by molecular oxygen using a catalyst of activated charcoal dispersed in aqueous ethanol. The DHA product is reasonably stable at low temperature (— 10 C). A dimeric form of DHA, bisdehydroascorbic acid (or BDHA), is also known. This substance is isolatable in crystalline form and may be obtained from DHA by dissolving the latter in nitromethane, boiling the solution and... 

---

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , , ]

---