Sulfated glycosaminoglycan-derived oligosaccharides produced from chicken connective tissue promote iron uptake in a human intestinal Caco-2 cell line

- Food-grade sulfated glycosaminoglycans are isolated from chicken connective tissues.
- Enzymatic depolymerisation of glycosaminoglycans improve their antioxidant capacity.
- Fe uptake by Caco-2 cells is enhanced by the effect of the depolymerisation.
- The chicken connective tissues represent a valuable source of bioactive compounds.

Food grade sulfated glycosaminoglycan (GAG) polysaccharides were successfully extracted from chicken cartilage and skin. Their respective oligosaccharides were obtained by bovine testicular hyaluronidase digestion. The antioxidant capacity was analyzed to determine the possible mechanism explaining how GAGs promote iron uptake by the Caco-2 cells. The sulfated GAG oligosaccharides derived from cartilage possessed the greatest DPPH scavenging and ferric reducing activities (p < 0.05), but limited ferrous chelating activities. Both the cartilage and skin sulfated GAG polysaccharides showed greater ferritin formation compared to the negative control (p < 0.05). Depolymerisation of GAG polysaccharides to oligosaccharides further improved ferritin formation by twofold. This research establishes that chicken sulfated GAG polysaccharides can enhance iron uptake by Caco-2 cells. The enhanced iron uptake through enzymatic GAG depolymerisation could be due to the combined effects of reduced molecular weight, increased amount of hydroxyl terminal groups and ferric reducing activities.