Structural Characterization of Zinc-Sucrose Complex and Its Ability to Promote Zinc Absorption in Caco-2 Monolayer Cells and Mice

Sucrose emerges as a metal-ion chelatingagent with excellent stabilitythat may increase metal-ion absorption. This study aimed to characterizethe structure of zinc-sucrose complex and investigate its abilityto promote zinc absorption in Caco-2 monolayer cells and mice. Basedon the results of the inductively coupled plasma emission spectrometer(ICP-ES), scanning electron microscopy-energy-dispersive X-rayspectroscopy (SEM-EDX), and Fourier transform infrared spectroscopy(FT-IR), it can be inferred that zinc and sucrose were chelated ata 1:1 ratio, with the hydroxyl groups playing a significant role.The Caco-2 monolayer cell model revealed that zinc-sucrosecomplex increased the amount of zinc uptake, retention, and transportin a dose- and time-dependent manner. Through the upregulation ofgenes and proteins for ZIP4, MT1, and DMT1, treatment with zinc-sucrosecomplex improved the proportion of absorbed zinc utilized for transportcompared to ZnCl2 (26.21 & PLUSMN; 4.96 versus 8.50 & PLUSMN; 1.51%). Pharmacokinetic analysis of mice confirmed thezinc absorption-promoting effect of zinc-sucrose complex, asindicated by the considerably higher serum zinc level (4.16 & PLUSMN;0.53 versus 2.56 & PLUSMN; 0.45 mg/L) and intestinalZIP4, MT1, and DMT1 gene expression than ZnCl2. Furthertreatment of different zinc channel inhibitors and CETSA demonstratedthe direct interaction of zinc-sucrose complex with ZIP4 proteinand ZIP4-mediated cellular transport of zinc-sucrose complex.These findings provide a novel insight into the zinc absorption-promotingmechanism of zinc-sucrose complex, which could be used as aningredient in functional foods to treat zinc deficiency.