School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.
Food Funct. 2019 Apr 17;10(4):1893-1902. doi: 10.1039/c8fo01845f.
Leaves of Cyclocarya paliurus (CP) have a potential antihyperglycemic effect, but its active compositions responsible for the beneficial properties remain unclear. The CP extract exhibited remarkable α-glucosidase inhibitory activity with an IC50 value of 31.5 ± 1.05 μg mL-1, much lower than that of the positive control acarbose (IC50 = 296.6 ± 1.06 μg mL-1). To identify the specific α-glucosidase inhibitors from the CP extract, affinity ultrafiltration coupled with ultra-performance liquid chromatography and quadrupole-time-of-flight mass spectrometry (UF-UPLC-Q/TOF-MS/MS) was developed and 11 potential α-glucosidase inhibitors from CP extract were identified. In vitro α-glucosidase inhibitory assay verified that quercetin-3-O-glucuronide, kaempferol-3-O-rhamnoside, quercetin, kaempferol, asiatic acid and genistein were primarily responsible for the α-glucosidase inhibitory activity of the CP extract. Further, a hypoglycemia test also verified that these α-glucosidase inhibitors had the potential to reduce post-prandial hyperglycaemia in C57BL/6 mice. Moreover, the molecular docking study revealed that these identified α-glucosidase inhibitors more easily occupy the active sites of α-glucosidase than does the positive control acarbose. These findings suggest the CP tea leaves are the potential source of a hypoglycaemic agent.
青钱柳叶具有潜在的降血糖作用，但负责其有益特性的活性成分仍不清楚。青钱柳提取物表现出显著的α-葡萄糖苷酶抑制活性，IC50 值为 31.5 ± 1.05 μg mL-1，远低于阳性对照阿卡波糖（IC50 = 296.6 ± 1.06 μg mL-1）。为了从青钱柳提取物中鉴定出特定的α-葡萄糖苷酶抑制剂，开发了亲和超滤结合超高效液相色谱和四极杆飞行时间质谱（UF-UPLC-Q/TOF-MS/MS），从青钱柳提取物中鉴定出 11 种潜在的α-葡萄糖苷酶抑制剂。体外α-葡萄糖苷酶抑制试验验证了槲皮素-3-O-葡萄糖醛酸苷、山奈酚-3-O-鼠李糖苷、槲皮素、山奈酚、齐墩果酸和染料木黄酮是青钱柳提取物α-葡萄糖苷酶抑制活性的主要原因。此外，低血糖测试还验证了这些α-葡萄糖苷酶抑制剂具有降低 C57BL/6 小鼠餐后高血糖的潜力。此外，分子对接研究表明，这些鉴定出的α-葡萄糖苷酶抑制剂比阳性对照阿卡波糖更容易占据α-葡萄糖苷酶的活性部位。这些发现表明青钱柳茶是一种降血糖药物的潜在来源。
