Abstract:

A kind of polysaccharide named MT-α-glucan was isolated and purified from the fruit body of Grifola frondosa. The dose-effect and time-effect relationships of MT-α-glucan were studied. The effect of MT-α-glucan on fasting blood glucose, 24 h post-treatment blood glucose, oral blood glucose tolerance, muscle glycogen content in KKay diabetic mice and the activity of α-glucosidase in vitro were investigated. Results showed that MT-α-glucan at the dosages of 112, 225 mg/kg bw and 450mg/kg bw had significant hypoglycemic effect and the strongest hypoglycemic effect was observed at the dosage of 450mg/kg bw at 8 h post-administration. However, blood glucose was restored to original level at 24 h post-administration. Consecutive administrations of MT- α -glucan at the dosage of 450 mg/kg bw and 150 mg/kg bw exhibited an obvious hypoglycemic effect on fasting blood glucose, blood glucose level at 24 h post-administration, and an increase effect on oral blood glucose tolerance and muscle glycogen content of KKay diabetic mice. In addition, MT- α -glucan had significant inhibitory effect onα-glucosidase activity in vitro. Therefore, MT-α-glucan had obvious hypoglycemic effect, which might be related to its inhibitory effect onα -glucosidase activity.

Key words: Grifola frondosa, fruit body, polysaccharide, hypoglycemic effect, α-glucosidase inhibitor