Polysaccharide from Lycium barbarum L. leaves enhances absorption of endogenous calcium, and elevates cecal calcium transport protein levels and serum cytokine levels in rats

摘要

A high-mineral polysaccharide (LP) was extracted from Lycium barbarum L. leaves, and the absorption of endogenous calcium, iron, and zinc was evaluated in Caco-2 cells and rat models. The absorption of these minerals ranged from 2.7 to 5.9% in Caco-2 cells, compared with 60.5-81.9% in rat models. LP had a compact globular conformation at pH similar to 7.2 when co-cultured with Caco-2 cells, and degraded to a loosely linear structure at pH similar to 6.7 in rat cecum. The degraded polysaccharides didn't change the mucosal morphometry but caused higher expression of calcium transporter 1 (CAT1) and zinc transporter 1 (ZIP1) proteins in rat cecum. Furthermore, fermentation of polysaccharides in cecum also caused elevated levels of serum cytoldnes, including TNF-alpha and IL-6. GL polysaccharides could increase the bioavailability of endogenous calcium via changes in the molecular conformation and through upregulation of the expression of mineral transporter proteins. (C) 2017 Elsevier Ltd. All rights reserved.