Mn3+-saturated bovine lactoferrin as a new complex with potential prebiotic activities for dysbiosis treatment and prevention - On the synthesis, chemical characterization and origin of biological activity

A new bioactive compound, Mn3+-saturated bovine lactoferrin (Mn2-bLf) was obtained. It was stable under physiological conditions (pH ≈ 7.5) although gradually releases Mn2+ ions under the simulated intestinal conditions (pH ≈ 6.5). This feature might be utilized for controlled delivery of Mn2+ ions to biological targets, among others to the probiotic strains of lactic acid bacteria whose growth is manganese-dependent. The Mn3+ modified bLf stimulates the growth of standard Lactobacillus plantarum and Lactobacillus rhamnosus, as well as the strains isolated from commercially available probiotic preparations, while the naturally occurring Fe-free and Fe-saturated forms of this protein are inactive. The uptake of manganese by Lactobacilli from Mn2-bLf added to culture supernatant was confirmed. Mn2-bLf was non-cytotoxic for Caco-2, CT-26 and HT-29 intestinal epithelial cells even up to 10 mg/ml concentration. Mn2-bLf due to stimulation of the growth of Lactobacilli and lack of toxicity, can be considered as an innovative ingredient of the prebiotic composition.