Gastric Stability of Ferritin Protein Cage and Its Bio-Mineral: Implication Towards Potential Dietary Iron Supplement

Abstract

Anemia is a serious global public health problem affecting around 2 billion people worldwide. About 50% of anemic cases are related to iron deficiency anemia (IDA), making it the most prevalent nutritional disorder. The currently available oral iron supplements (mainly inorganic iron salts or complexes such as ferrous sulphate, ferrous ascorbate etc.) are taken in the form of a “Fe2+ burst,” and are associated with oxidative stress, infections and gastrointestinal upsets. In this work, we investigated the gastric stability of “ferritins”, for using them as potential dietary iron supplement to address these limitations. Ferritins - the cellular iron repositories, self-assembled protein nanocage architectures; are naturally bestowed with iron-scavenging (up to 4500 Fe atoms) and anti-oxidative properties. The in vitro data shows that though unmodified ferritins are quite resistant to conformational changes induced by acidic pH (in stomach environment), their cage integrity and mineral retention is compromised on longer incubation and higher concentrations of pepsin. To further retain its structural and functional aspects under gastric conditions, we fabricated the ferritins with an enteric coating biopolymer. The modified ferritins exhibited better cage integrity and slow iron release profile, implying that the biopolymer can potentially help ferritin proteins to stabilize and retain its iron bio-mineral content throughout the digestive tract, preventing any unwanted leakage till the intact ferritins are internalized/absorbed by intestinal receptors.