PENTOXIFYLLINE - A HYDROXYL RADICAL SCAVENGER

Pentoxifylline (PTX), a tri-substituted purine and xanthine derivative , has been used for several years to improve microcirculation because of its hemorheological properties. PTX has also antifibrotic and anti- inflammatory effects. We studied the reaction of PTX with the hydroxyl radical and superoxide anion. Hydroxyl radical was generated by a mix ture of ascorbic acid, H2O2 and Fe (III)-EDTA. We evaluated the iron-d ependent degradation of deoxyribose, mediated by hydroxyl radical, in the presence of different concentrations of PTX (from 0.05 to 3 mM), m easuring the degradation products of deoxyribose that react with 2-thi obarbituric acid (TEA). The reaction of PTX with hydroxyl radical occu rred with a rate constant of (1.1 +/- 0.2) x 10(10) M(-1)/s. These res ults support the properties of PTX as a hydroxyl radical scavenger. So me authors verified that PTX decreases the release of superoxide anion from activated neutrophils. We studied the effect of PTX as a scaveng er of superoxide generated in vitro by a hypoxanthine-xanthine oxidase system. PTX was not a superoxide anion scavenger in this system.