2003 Volume 49 Issue 6 Pages 434-436
An attempt to synthesize 6-hydroxypyridoxine (OPN), hydroxylation on C-6 of pyridoxine (PN) by hydroxyl radical (OH⋅), was conducted. Application of two well-known OH generating reactions, i.e. the Fenton reaction and the Fe2+-EDTA/ascorbate reaction, were unsuccessful, as large amounts of by-products were formed. Although generation of OH by autoxidation of ascorbic acid in the absence of metal ions was slow, by-products were formed in small quantities, and OPN was easily obtained in colorless crystals. Its structure was confirmed by spectral analyses. OPN was comparable to polyphenols such as (+)-cat-echin, rutin and gallic acid in the antioxidative activity against linoleic acid peroxidation, and was an effective DPPH radical scavenger, though the DPPH radical-scavenging activity of OPN was somewhat lower than that of the polyphenols. PN was relatively inactive under the conditions used here, indicating that the introduction of a hydroxyl group on C-6 of PN greatly enhanced both activities.