[The comparison of alpha-lipoic acid, melatonin, vitamin C and trolox effectiveness in decreasing DNA stand brakes and increasing plasma antioxidant power].

Unlabelled: Human plasma contains different antioxidants which may be important in the maintenance of an antioxidant status. The aim of this study was to compare the effect of exogenous antioxidants (vitamin C, trolox, alpha-lipoic acid and melatonin) on DNA standard brakes level and antioxidant activity of plasma.

Material And Methods: Blood was obtain from 24 healthy volunteers from 19-23 of age and centrifuge. Vitamin C (vit C), trolox (water soluble vitamin E), lipoic acid (LA) or melatonin (MEL) were added separately to the plasma right before assay. Final concentration of each antioxidant in plasma was 1 mmol. Antioxidant properties of plasma and plasma with antioxidants were evaluated by three methods: level of DNA damages, ferric reducing ability of plasma (FRAP), scavenging of DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical.

Results: We showed that vit C and trolox have strong ability to reduce bivalent iron (p<0.001 and p<0.001, respectively). The highest protective effect on hydroxyl radical-induced DNA damage was observed for trolox and LA (p<0.001 and p<0.01, respectively). All antioxidants possessed weak ability to scavenge DPPH radicals.

Conclusion: In our study trolox and vitamin C effectively diminished DNA oxidative damages and possessed the highest antioxidant properties. Melatonin and lipoic acid decreased DNA damages but did not increase plasma antioxidant ability.