Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, College of Aninal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning 110866, People's Republic of China.
Key Laboratory of Healthy Food Nutrition and Innovative Manufacturing, College of Food Science, Shenyang Agricultural University, Shenyang, Liaoning 110866, People's Republic of China.
J Agric Food Chem. 2020 Aug 5;68(31):8223-8231. doi: 10.1021/acs.jafc.0c02720. Epub 2020 Jul 22.
Mulberry leaf is a common vegetable with a variety of beneficial effects, such as hypoglycemic activity. However, the underlying mechanism of its hypoglycemic effect have not been fully revealed. In this study, two flavonoid derivatives were isolated from mulberry leaves, a new geranylated flavonoid compound () and its structural analogue (). The structures of compounds and were elucidated using spectroscopic analysis. To study the potential hypoglycemic properties of these compounds, their regulatory effects on protein tyrosine phosphatase 1B (PTP1B) were investigated. In comparison to oleanolic acid, compounds and showed significant inhibitory activities (IC = 4.53 ± 0.31 and 10.53 ± 1.76 μM) against PTP1B, the positive control (IC = 7.94 ± 0.76 μM). Molecular docking predicted the binding sites of compound to PTP1B. In insulin-resistance HepG2 cell, compound promoted glucose consumption in a dose-dependent manner. Furthermore, western blot and polymerase chain reaction analyses indicated that compound might regulate glucose consumption through the PTP1B/IRS/PI3K/AKT pathway. In conclusion, geranylated flavonoids in mulberry leaves inhibite PTP1B and increase the glucose consumption in insulin-resistant cells. These findings provide an important basis for the use of mulberry leaf flavonoids as a dietary supplement to regulate glucose metabolism.
桑叶是一种常见的蔬菜，具有多种有益作用，如降血糖活性。然而，其降血糖作用的潜在机制尚未完全揭示。在这项研究中，从桑叶中分离得到了两种类黄酮衍生物，一种新的香叶基化黄酮化合物（）及其结构类似物（）。通过光谱分析阐明了化合物和的结构。为了研究这些化合物的潜在降血糖特性，研究了它们对蛋白酪氨酸磷酸酶 1B（PTP1B）的调节作用。与齐墩果酸相比，化合物和对 PTP1B 表现出显著的抑制活性（IC = 4.53 ± 0.31 和 10.53 ± 1.76 μM），阳性对照（IC = 7.94 ± 0.76 μM）。分子对接预测了化合物与 PTP1B 的结合位点。在胰岛素抵抗 HepG2 细胞中，化合物以剂量依赖的方式促进葡萄糖消耗。此外，western blot 和聚合酶链反应分析表明，化合物可能通过 PTP1B/IRS/PI3K/AKT 通路调节葡萄糖代谢。总之，桑叶中的香叶基化类黄酮抑制 PTP1B 并增加胰岛素抵抗细胞中的葡萄糖消耗。这些发现为将桑叶类黄酮作为调节葡萄糖代谢的膳食补充剂提供了重要依据。
