Background:
Free radical processes are known to induce oxidative damage in biomolecules and thus, play an important role in the etiology of a number of diseases including cancer. Phytic acid (myo-inositol hexaphosphate, IP6) is a naturally occurring carbohydrate widely found in fi berrich foods and also contained in almost all mammalian cells. This compound demonstrates various biological activities. The aim of this study was to clarify whether phytic acid possesses the ability to inhibit autooxidation and Fe(II)/ascorbate-induced peroxidation of linoleic acid, to scavenge of hydrogen peroxide, and chelate ferrous ions.

Material and Methods:
The antioxidant properties of the IP6 at various concentrations (1-500 μM) have been evaluated by using the assays based on hydrogen peroxide scavenging and ferrous metal ions chelating activity determination. The eff ect of IP6 (1-500 μM) on autooxidation and Fe(II)/ascorbate-induced lipid peroxidation in micelles of linoleic acid after 24 h incubation was investigated using a reverse-phase high-performance liquid chromatography (RP-HPLC) with UV detection.

Results:
The Fe(II) chelating eff ects of IP6 were concentration-dependent. IP6 exhibited 11,9%, 58,6%, 69,3%, 87,1% of ferrous ions chelation at 10 μM, 50 μM, 100 μM, 500 μȂ , respectively. IP6 at 100 μM and 500 μM eff ectively inhibited the disappearance of linoleic acid, both in the absence and the presence of Fe(II)/ascorbate. The inhibitory effect of IP6 on Fe(II)/ascorbate-induced lipid peroxidation was lower due to its direct interaction with Fe(II) ions. In the absence of Fe(II)/ascorbate, IP6 at 100 μM and 500 μM signifi cantly suppressed decomposition of linoleic acid hydroperoxides. It was incapable of scavenging of hydrogen peroxide

Conclusions:
IP6 can act as a natural antioxidant in vitro. The obtained results suggest that it can play an important role in modulating lipid hydroperoxide level in biological systems.