Abstract: Objective: to study the hypoglycemic activity of avicularin and guaijaverin in guava leaves. Methods: Reversed-phase high performance liquid chromatography was used to determine the content of avicularin and guaijaverin in guava leaves from different months. Fat cell hypoglycemic model was established to evaluate hypoglycemic activity of guava leaves extract, avicularin and guaijaverin respectively. Western-blotting was used to analysis the GLUT4 expression on the fat cell membrane. Free fatty acids as another index was also determined by Free fatty acid Kit. Results: the guaijaverin and avicularin content in guava leaves showed great difference in different months, the higher content and hypoglycemic activity was both existed in 6-9 months. The guava leaves extract, guajava and avicularin could significantly promote GLUT4 protein expression on the fat cell membrane and could also significantly inhibit the release of free fatty acids. Conclusion: guaijaverin and avicularin were the main bioactive components of guava leaves with hypoglycemic activity and free fatty acids release inhibition.

Key words: Guava leaves, guaijaverin, avicularin, hypoglycemic activity, GLUT4, free fatty acid