Wang Mengting, Mao Haiguang, Ke Zhijian, Chen Jianchu, Qi Lili, Wang Jinbo
School of Biological and Chemical Engineering, NingboTech University, Ningbo, China.
College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China.
Front Pharmacol. 2024 Mar 11;15:1284268. doi: 10.3389/fphar.2024.1284268. eCollection 2024.
The hypoglycemic effects of Chinese bayberry leaves proanthocyanidins (BLPs) have been demonstrated. It is unclear, nevertheless, whether BLPs reduced postprandial blood glucose levels by regulating glucose uptake and glucose transport. This study investigated the effect of BLPs (25, 50, and 100 μg/mL) on glucose uptake and glucose transport in human intestinal epithelial cells (Caco-2 cells). The uptake of 2-Deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl) amino]-D-glucose (2-NBDG) and disaccharidases activity in Caco-2 cells were measured. The glucose transport ability across the cell membrane was determined using the established Caco-2 monolayer model. The transcript and protein levels of key glucose transporters were analyzed using real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting, respectively. The results showed that BLPs significantly decreased glucose uptake and disaccharidases activity ( < 0.05). Otherwise, BLPs treatment obviously inhibited glucose transport across the Caco-2 monolayer in both simulated-fast (5 mM glucose) and simulated-fed (25 mM glucose) conditions. It was attributed to the suppression of glucose transporter2 (GLUT2) and sodium-dependent glucose cotransporter 1 (SGLT1) by BLPs. BLPs were found to significantly downregulated the transcript level and protein expression of glucose transporters ( < 0.05). Meanwhile, the mRNA expression of phospholipase C (PLC) and protein kinase C (PKC) involved in the signaling pathway associated with glucose transport were decreased by BLPs. These results suggested that BLPs inhibited intestinal glucose transport via inhibiting the expression of glucose transporters. It indicated that BLPs could be potentially used as a functional food in the diet to modulate postprandial hyperglycemia.
杨梅叶原花青素（BLPs）的降血糖作用已得到证实。然而，尚不清楚BLPs是否通过调节葡萄糖摄取和葡萄糖转运来降低餐后血糖水平。本研究调查了BLPs（25、50和100μg/mL）对人肠上皮细胞（Caco-2细胞）葡萄糖摄取和葡萄糖转运的影响。测定了Caco-2细胞中2-脱氧-2-[(7-硝基-2,1,3-苯并恶二唑-4-基)氨基]-D-葡萄糖（2-NBDG）的摄取和双糖酶活性。使用已建立的Caco-2单层模型测定葡萄糖跨细胞膜的转运能力。分别采用实时定量聚合酶链反应（RT-qPCR）和蛋白质印迹法分析关键葡萄糖转运蛋白的转录水平和蛋白水平。结果表明，BLPs显著降低了葡萄糖摄取和双糖酶活性（P<0.05）。此外，在模拟空腹（5mM葡萄糖）和模拟进食（25mM葡萄糖）条件下，BLPs处理均明显抑制了葡萄糖跨Caco-2单层的转运。这归因于BLPs对葡萄糖转运蛋白2（GLUT2）和钠依赖性葡萄糖协同转运蛋白1（SGLT1）的抑制。发现BLPs显著下调葡萄糖转运蛋白的转录水平和蛋白表达（P<0.05）。同时，BLPs降低了参与葡萄糖转运相关信号通路的磷脂酶C（PLC）和蛋白激酶C（PKC）的mRNA表达。这些结果表明，BLPs通过抑制葡萄糖转运蛋白的表达来抑制肠道葡萄糖转运。这表明BLPs有可能作为一种功能性食品用于饮食中以调节餐后高血糖。
