College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, PR China.
School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
Fitoterapia. 2022 Oct;162:105263. doi: 10.1016/j.fitote.2022.105263. Epub 2022 Aug 5.
α-Glucosidase and protein tyrosine phosphatase 1B (PTP1B) signaling pathway dual regulators decrease postprandial blood glucose levels and improve insulin sensitivity, making it a new treatment strategy for type 2 diabetes. This study examined in vitro antidiabetic activities of 8-C-ascorbyl-(-)-epigallocatechin (AE), found in oolong tea. AE inhibited α-glucosidase (IC = 142.8 μM) with activity higher than that of acarbose (IC = 250.2 μM). AE significantly promoted glucose-consumption and activated the insulin signaling pathway through enhancing the protein levels of p-GSK3β and p-Akt and inhibiting the expression of PTP1B, along with slightly inhibitory activity against PTP1B. Docking analysis showed AE inhibited α-glucosidase activity via binding to the catalytic site through hydrogen bonds and Pi-Pi interactions, as well as a good shape match to the active pocket. In addition, AE could relieve oxidative damage and possessed good antioxidant capacity. Taken together, the results of this study indicate that AE exhibits antidiabetic activity in vitro, making it a potential functional food ingredient and drug candidate for management of type 2 diabetes.
α-葡萄糖苷酶和蛋白酪氨酸磷酸酶 1B（PTP1B）信号通路双重调节剂降低餐后血糖水平并改善胰岛素敏感性，成为 2 型糖尿病的新治疗策略。本研究考察了乌龙茶中发现的 8-C-抗坏血酸-(-)-表没食子儿茶素（AE）的体外抗糖尿病活性。AE 抑制α-葡萄糖苷酶（IC=142.8μM）的活性高于阿卡波糖（IC=250.2μM）。AE 可显著促进葡萄糖消耗，并通过增强 p-GSK3β 和 p-Akt 的蛋白水平以及抑制 PTP1B 的表达，激活胰岛素信号通路，同时对 PTP1B 具有轻微抑制作用。对接分析表明，AE 通过氢键和 Pi-Pi 相互作用与催化位点结合，从而抑制α-葡萄糖苷酶活性，同时与活性口袋具有良好的形状匹配。此外，AE 可以减轻氧化损伤，具有良好的抗氧化能力。综上所述，本研究结果表明，AE 在体外具有抗糖尿病活性，使其成为 2 型糖尿病管理的潜在功能性食品成分和药物候选物。
