Effect on free radical processes of some ascorbic acid analogues

Ascorbic acid, present in plasma from humans at concentrations of 50 to 200 mumol/l, has multiple antioxidant properties. Structural modification of this vitamin by the introduction of lipophilic moieties has allowed to the development of ascorbate esters and ethers active as free radical quenchers. Thus, a new series of ascorbic acid analogues possessing one or two aromatic rings was prepared in an attempt to synthesize potent antioxidants with lipophilic properties. Substituted 3-hydroxy furan-2 (5H)-ones and in some cases, dihydrofuro[3,4-b]pyrones were prepared. The synthesized compounds were evaluated for their antioxidant activity in vitro. So, 4-(4-methoxybenzoyl)-3-hydroxy-5-phenylfuran-2(5H)-one 3e (IC50 = 3.06 x 10(-4) M) was found to be the most effective in scavenging the superoxide anion, whereas 4-benzoyl-3-hydroxy-5-(3,4-dimethoxyphenyl)furan- 2(5H)-one 3d (IC50 = 1.38 x 10(-4) M) was the most active in inhibiting, lipid peroxidation.