Relationship between plasma levels of Zinc and lipid oxidizability in diluted plasma.

Background: Zinc (Zn) is an essential trace element that has been regarded as having
antioxidant properties. Some epidemiological studies have indicated the protective effect of Zn on
lipid and lipoprotein peroxidation, but the underline mechanism is poorly understood. This study
was conducted to evaluate the relationship between plasma Zn and copper-induced lipid
peroxidation parameters in diluted plasma.
Methods and Materials: In 100 healthy adult men (36.82 ± 10.33 years), fasting plasma levels of
Zn, lipids, bilirubin, urate, malondialdehyde (MDA) and copper induced lipid peroxidation were
evaluated. Lipid oxidation estimated by monitoring the change of conjugated dienes in 60-fold
diluted plasma after addition of 60 μM Cu2+ and MDA was determined by thiobarbituric acid
method.
Results: A significant correlation (r=0.24, p=0.024), between Lag-time (104 ± 33 min) and
plasma Zn levels (128.76 ± 108.33 μg/dl) was found; however, no significant correlation was found
between other parameters of lipid oxidation kinetics and MDA with plasma Zn levels.
Conclusion: Based what the results indicated there is a delay in Cu-induced plasma lipid
oxidation by higher levels of plasma Zn, but Zn level has no effect on finals oxidation products. It
seems that Zn interferes with for Cu in the formation of an active oxidizing complex.