番石榴叶中广寄生苷和番石榴苷的降糖作用

目的：研究番石榴叶、广寄生苷和番石榴苷的降糖活性和相关性。方法：采用反相高效液相色谱法测定不同月份番石榴叶中番石榴苷和广寄生苷的含量；建立降糖脂肪细胞模型，测定不同季节番石榴叶提取物的降糖活性；给药干预后，测定细胞培养液中游离脂肪酸的含量，采用Western blotting法测定脂肪细胞膜葡萄糖转运蛋白4（glucose transporter 4，GLUT4）表达。结果：6-9月份番石榴叶中番石榴苷和广寄生苷的含量较高，同时6-9月份番石榴叶的降糖活性也最好，降糖活性与化合物含量存在正相关性。番石榴叶提取物、番石榴苷和广寄生苷均能显著促进脂肪细胞膜上GLUT4蛋白的表达；番石榴叶提取物、番石榴苷和广寄生苷均能显著抑制游离脂肪酸的释放，降糖活性和抑制脂肪分解也存在正相关性。结论：番石榴苷和广寄生苷两种黄酮苷类化合物是番石榴叶降糖、抑制游离脂肪酸释放的主要活性物质基础。

Hypoglycemic Activity of Avicularin and Guaijaverin in Guava Leaves

Objective: To study the hypoglycemic activity of avicularin and guaijaverin in guava leaves. Methods: Reversedphase
high performance liquid chromatography (RP-HPLC) was used to determine the content of avicularin and guaijaverin
in guava leaves in different months of the year. The fat cell model was established to evaluate hypoglycemic activity of
the ethanol extract of guava leaves, avicularin and guaijaverin respectively. Western blotting was used to analyze GLUT4
expression on the fat cell membrane. Free fatty acids as another index were also determined using a fatty acid kit. Results:
The contents of guaijaverin and avicularin in guava leaves showed great difference in different months, and guava leaves
had higher contents and hypoglycemic activity both between June and September. The guava leaf extract, guajava and
avicularin could all significantly promote GLUT4 protein expression on the fat cell membrane and significantly inhibit the
release of free fatty acids. Conclusion: Guaijaverin and avicularin are the major bioactive components in guava leaves with
hypoglycemic activity and inhibitory capacity against free fatty acid release.