天竺桂多酚提取物降血糖活性研究

Hypoglycemic activity of polyphenol-rich extract from Cinnamomun japonicum Sieb

目的研究天竺桂提取物中多酚的结构类型及降糖活性。方法运用HPLC及ESI-MS方法确定多酚的结构,利用噻唑蓝法测定细胞活力评价天竺桂提取物对棕榈酸或过氧化氢损伤的INS-1细胞的保护作用,利用db/db自发2型糖尿病小鼠观察天竺桂提取物对糖尿病小鼠糖代谢的影响。结果天竺桂提取物中多酚主要为B-型多酚;提取物能剂量依赖地保护棕榈酸或过氧化氢诱导损伤的INS-1细胞,并且显著抑制过氧化氢引起的INS-1细胞内活性氧增加;200 mg/kg剂量给药4周后降低了db/db小鼠空腹血糖,改善了口服糖耐量,显著增加了胰岛素耐量。结论天竺桂多酚为B-型多酚,具有一定的降糖活性,其机制可能为减少胰岛β细胞活性氧水平,抵抗氧化应激对β细胞的损伤,从而保护胰岛β细胞。

AIM To explore the structure and hypoglycemic activity of the polyphenols-rich extract isolated from Cinnamomun japonicum Sieb. METHODS HPLC and ESI-MS methods were employed to characterize their structures. The biological activity of the extract was determined on pancreatic INS-1β cells and db/db type 2 dia- betic mice model. The effects of the extract on the vitality of INS-1 cell under palmitate or H2O2 stimulation were examined. RESULTS The main polyphenols found in C. japonicum extracts were identified as B-type polyphe- nols, and that the extract could protect INS-1 cells from palmitate or HzO2 damage, The reaction oxygen level was also significantly reduced in the extract-treated INS-1 cells under H20= induction in a dose dependent manner. Af- ter the administration of the extract once daily for 4 weeks at the dosage of 200 mg/kg, the fasting blood glucose of db/db mice was reduced, and the oral glucose and insulin tolerances were also improved. CONCLUSION B- type polyphenols from C. japonicum have anti-diabetic activity. It could protect pancreatic beta cells from palmitate or H2O2 induced damage via reducing the intracellular reaction oxygen level, which could be one possible reason for the improvement in the symptoms of diabetes in db/db mice.