Mn(II)-Mediated Self-Assembly of Tea Polysaccharide Nanoparticles and Their Functional Role in Mice with Type 2 Diabetes

Abstract

Tea polysaccharide (TPS) is a bioactive compound that has attracted increasing attention for its health effect on regulating the metabolism of glucose and lipid. Moreover, due to their good biocompatibility and biodegradability, TPS-based nanoparticles have emerged as effective nanocarriers for the delivery of bioactive molecules. In this study, we developed a TPS-based biocarrier system for the orally targeted administration of Mn(II) ions and investigated their antidiabetic effects in C57BL/6 mice with HFD/streptozotocin (STZ)-induced T2DM. Mn(II)-loaded TPS-based nanoparticles (MTNPs) were synthesized, in which negatively charged functional groups in protein and uronic acid in TPS conjugates would act as binding sites for Mn(II) ions, which is responsible for the cross-linking reaction of MTNP. The resulting MTNP had a spherical shape and a mean particle size of around 30 nm with a Mn(II) ion content of 2.24 ± 0.13 mg/g. In T2DM mice, we discovered that MTNP treatment significantly lowered blood glucose levels and improved glucose intolerance. Furthermore, the impact of MTNP on the recovery of FINS, the homeostatic index of insulin resistance (HOMA-IR), and the homeostatic index of β-cell (HOMA β-cell) levels was significantly larger (p < 0.05) than TPS alone, demonstrating that Mn(II) ions can enhance TPS's ability to repair HFD/STZ-induced β-cell damage. Mn(II) ions in MTNP not only acted as cofactors to increase the exocytosis of insulin secretory cells by upregulating the expression of Ca(II)/calmodulin-dependent protein kinase II (CaMK II) but also promoted TPS's lipid-lowering effect in T2DM mice by inhibiting glucogenesis and regulating the lipid metabolism. Our findings suggest that Mn(II) ions can be used not only as cross-linkers in the formation of nanoparticulated TPS but also as cofactors in improving the functional role of TPS in regulating the glucose and lipid metabolism, which will provide insights into the development of TPS-based drug delivery systems for the prevention of type 2 diabetes.

Onchidium struma polysaccharides exhibit hypoglycemic activity and modulate the gut microbiota in mice with type 2 diabetes mellitus

“…38 HOMA-β is an important pathophysiological characteristic of diabetic mice used to assess pancreatic β-cell dysfunction. 39 In this study, OsPs intervention attenuated HSHF/STZ-induced high levels of HOMA-IRI and HOMA-β index, and low HOMA-ISI index, suggesting that insulin resistance and impaired pancreatic β-cell function can be effectively improved by OsPs treatment.…”

Efficient Utilization of Tea Resources through Encapsulation: Dual Perspectives from Core Material to Wall Material

“…The levels of polysaccharide, uronic acid, and protein that were conjugated to tea polysaccharide were found to account for 58.85 ± 2.35%, 7.10 ± 0.14%, and 25.25 ± 0.50%, respectively. 86 The resulting nanoparticles could regulate glucose and lipid metabolism in type 2 diabetic mice. Tea polysaccharide conjugates with heating at 110 °C for 3 days (241 kDa) could improve their emulsifying activity without negatively affecting the antioxidant activity.…”

“…Subsequently, Zheng et al reported tea waste microcrystalline cellulose as the stabilizer of the Pickering emulsion, which increased the stability of lycopene against photodegradation and thermal degradation and exhibited high stability and bioavailability during in vitro simulated digestion. As shown in Figure , Fan et al developed tea polysaccharide nanoparticles used for orally targeted administration of Mn­(II) ions, and the binding sites for Mn­(II) ions were negatively charged groups in protein and uronic acid in tea polysaccharide conjugates. The levels of polysaccharide, uronic acid, and protein that were conjugated to tea polysaccharide were found to account for 58.85 ± 2.35%, 7.10 ± 0.14%, and 25.25 ± 0.50%, respectively .…”

“…As shown in Figure , Fan et al developed tea polysaccharide nanoparticles used for orally targeted administration of Mn­(II) ions, and the binding sites for Mn­(II) ions were negatively charged groups in protein and uronic acid in tea polysaccharide conjugates. The levels of polysaccharide, uronic acid, and protein that were conjugated to tea polysaccharide were found to account for 58.85 ± 2.35%, 7.10 ± 0.14%, and 25.25 ± 0.50%, respectively . The resulting nanoparticles could regulate glucose and lipid metabolism in type 2 diabetic mice.…”

“…Figure5. Schematic diagram of Mn(II)-mediated self-assembly of tea polysaccharide nanoparticles and their functional role in type 2 diabetic mice 86. TPS is a tea polysaccharide.…”