Synthesis and Characterization of an Antioxidative Galactomannan⁻Iron(III) Complex from Sesbania Seed

Galactomannan, a water-soluble polymer in the cell wall of leguminous plants, has been proven to possess anticancer and antioxidative activity. In this work, galactomannan with different molecular weights (GM-40 and GM-65) was obtained from Sesbania seeds and synthesized into galactomannan⁻iron(III) complexes, which are termed as GM-40-Fe and GM-65-Fe, respectively. These galactomannan⁻iron(III) complexes are intended to function as organic iron supplements to treat iron deficiency with the added benefit of antioxidative activity. The prepared galactomannan⁻iron(III) complexes were characterized for chemical composition, morphology, antioxidant capacity, and bioavailability in vitro. The results showed that galactomannan⁻iron(III) complexes could be produced with iron contents as high as 65.4 mg/g. Antioxidant assays indicated that both GM-40-Fe and GM-65-Fe exhibited antioxidant activities for scavenging radicals in vitro. The iron release/bioavailability assays showed that the iron was easily released into artificial gastric and intestinal juices, resulting in iron release rates of 88⁻94% over 300 min. These results suggest that galactomannan⁻iron(III) complexes synthesized from Sesbania seed polysaccharides are capable of being administered as organic iron supplements to patients with iron deficiency.