Structural characterization and calcium absorption‐promoting effect of sucrose‐calcium chelate in Caco‐2 monolayer cells and mice

Abstract

Sucrose emerges as a chelating agent to form a stable sucrose‐metal‐ion chelate that can potentially improve metal‐ion absorption. This study aimed to analyze the structure of sucrose‐calcium chelate and its potential to promote calcium absorption in both Caco‐2 monolayer cells and mice. The characterization results showed that calcium ions mainly chelated with hydroxyl groups in sucrose to produce sucrose‐calcium chelate, altering the crystal structure of sucrose (forming polymer particles) and improving its thermal stability. Sucrose‐calcium chelate dose dependently increased the amount of calcium uptake, retention, and transport in the Caco‐2 monolayer cell model. Compared to CaCl2, there was a significant improvement in the proportion of absorbed calcium utilized for transport but not retention (93.13 ± 1.75% vs. 67.67 ± 7.55%). Further treatment of calcium channel inhibitors demonstrated the active transport of sucrose‐calcium chelate through Cav1.3. Cellular thermal shift assay and quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR) assays indicated that the ability of sucrose‐calcium chelate to promote calcium transport was attributed to its superior ability to bind with PMCA1b, a calcium transporter located on the basement membrane, and stimulate its gene expression compared to CaCl2. Pharmacokinetic analysis of mice confirmed the calcium absorption‐promoting effect of sucrose‐calcium chelate, as evident by the higher serum calcium level (44.12 ± 1.90 mg/L vs. 37.42 ± 1.88 mmol/L) and intestinal PMCA1b gene expression than CaCl2. These findings offer a new understanding of how sucrose‐calcium chelate enhances intestinal calcium absorption and could be used as an ingredient in functional foods to treat calcium deficiency.Practical ApplicationThe development of high‐quality calcium supplements is crucial for addressing the various adverse symptoms associated with calcium deficiency. This study aimed to prepare a sucrose‐calcium chelate and analyze its structure, as well as its potential to enhance calcium absorption in Caco‐2 monolayer cells and mice. The results demonstrated that the sucrose‐calcium chelate effectively promoted calcium absorption. Notably, its ability to enhance calcium transport was linked to its strong binding with PMCA1b, a calcium transporter located on the basement membrane, and its capacity to stimulate PMCA1b gene expression. These findings contribute to a deeper understanding of how the sucrose‐calcium chelate enhances intestinal calcium absorption and suggest its potential use as an ingredient in functional foods for treating calcium deficiency.