Publication details
Interaction of Plant Polyphenols with Iron Ions
| Authors | |
|---|---|
| Year of publication | 2005 |
| Type | Article in Periodical |
| Magazine / Source | Chem. Listy |
| MU Faculty or unit | |
| Citation | |
| Keywords | Polyphenols; iron; ferrozin |
| Description | Polyphenols are secondary plant metabolites, which are a common part of the human diet. Their daily intake is estimated to be about 1 g a day. Some epidemiological studies expect a relationship between the consumption of polyphenol-rich foods or beverages and the prevention of cardiovascular diseases and cancer. These pathological conditions are connected with the excessive free radical production. There is a general view that the transient metals, especially iron and copper, can cause the formation of free radicals in vivo. The transient metal chelators are able to decrease the production of free radicals generated by the transient metals. We have studied the formation of complexes of the plant phenolic acids with ferrous and ferric ions. The spectroscopic studies indicate that only those phenolic acids with catechol moiety were capable of chelating iron ions at physiological pH 7.4. The rate of Fe2+ autooxidation was significantly influenced by the ligands used in the experiments. Polyphenolic acids with the 3,4-dihydroxyphenyl (catechol) moiety significantly increase the rate of autooxidation. The negative charge of the phenolic acid anions significantly promoted the rate of autooxidation. The results obtained corresponded with the theory, that the chelators with oxygen ligands, which would stabilize Fe3+, would also increase the rate of autooxidation. Conversely, polyphenols with only one phenolic hydroxyl stabilized Fe2+ and inhibited the rate of autooxidation, although not as significantly as the catecholic chelators had a stimulatory effect. |