Giovanni Monastra, Yula Sambuy, Simonetta Ferruzza, Daniela Ferrari and Giulia Ranaldi* Pages 1305 - 1311 ( 7 )
Background: Myo-inositol is a natural molecule with important therapeutic applications and an impaired oral absorption may result in a reduced clinical effect. Aim of this study was to determine if the combined oral administration of α-lactalbumin and myo-inositol in healthy subjects, could increase the plasma level of myo-inositol administered alone. In vitro studies on human differentiated intestinal Caco-2 cells were also conducted to identify the mechanisms involved in myo-inositol absorption.
Objective: The in vivo study was conducted on healthy volunteers in two phases. Subjects received a single oral myo-inositol dose. After 7 days washout, the same subjects were administered a single dose of myo-inositol and α-lactalbumin. Cmax, Tmax and AUC for myo-inositol in plasma were calculated from samples collected at different times. Transepithelial myo-inositol passage, with or without addition of digested α-lactalbumin, was measured in vitro in differentiated Caco-2 cells and compared to transepithelial electrical resistance and phenol red passage.
Results: The bioavailability of myo-inositol was modified by the concomitant administration of α- lactalbumin. Although peak concentration of myo-inositol at 180 min (Tmax) was similar for both treatments, administration of α-lactalbumin with myo-inositol in a single dose, significantly increased the plasma concentrations of myo-inositol compared to when administered alone. In vitro, myo-inositol absorption in Caco-2 cells was improved in the presence of digested α-lactalbumin, and this change was associated with an increase in tight junction permeability.
Conclusion: Better myo-inositol absorption when orally administered with α-lactalbumin can be beneficial in non-responder patients. Preliminary in vitro findings suggest that peptides deriving from α- lactalbumin digestion may modulate tight junction permeability allowing increased absorption of myoinositol.
Myo-inositol, α-lactalbumin, pharmacokinetics, healthy volunteers, bioactive peptides, bioavailability, absorption enhancers, intestinal permeability.
Department of Experimental Medicine, University of Rome , Council for Agricultural Research and Economics, Center for Food and Nutrition, Rome, Council for Agricultural Research and Economics, Center for Food and Nutrition, Rome, Department of Molecular Medicine, University of Rome , Council for Agricultural Research and Economics, Center for Food and Nutrition, Rome