Although rutin possesses more structural features than ferulic acid for
complexing metal ions, the ethanolic extracts of wheat flours exhibited more
potent chelating activity on Fe2+ than the buckwheat extracts. Lower antioxidative
capacity of rutin as metal chelator in comparison to ferulic acid (and
other hydroxycinnamic acids from wheat flour) might be due to steric hindrance
of the sugar moiety of rutin. The presence of some more potent chelating
component(s) in wheat flour extract might be responsible for its higher
chelating capacity. Significant Fe2+ chelating activities and inhibitory effects
were detected in wheat grain extracts (Y u et al., 2002) which is in correlation
with our results presented in the Figure 4. Furthermore, in the Fe2+ chelating
assay, wheat bran demonstrated superior chelating properties over the other
milling fractions, while wheat flour had the lowest chelating capacity (L i -
y a n a and S h a h i d i, 2007).