Objective:The aim of the study was to investigate the effect and its mechanism of pueraria flavonoids (PF) on improving the hypoglycemic effect of mulberry root bark (Morus alba L.) extract (ME). Method: Four groups of rats (n=5 for each) were given with starch(2 g·kg-1)in combination with ME(34.5 mg·kg-1)

PF(211.5 mg·kg-1)

mixture of ME and PF (ME-PF 250 mg·kg-1) or water

respectively. 1-deoxynojlrimycin(DNJ)

the main active component of ME for inhibition of α-glycosidase activity

was 20 mg·kg-1 in ME and ME-PF groups.The rat blood glucose levels were assayed in 2 hr after dosing. Another two groups of rats (n=5 for each) were used for single-pass small intestinal perfusion of ME and ME-PF

respectively

at DNJ equivalent concentration of 10 μmol·L-1. The DNJ concentrations in perfusion samples were determined by LC-MS/MS methods. Result: When ME was given in combination with PF

the increased blood glucose levels in rats after dosing with starch were significantly depressed. The area under the blood glucose concentration-time curve (AUC) from time 0 to 2 h of rats in ME-PF group was decreased by 40.8%

in comparison with those when given with only starch. While

the AUC in ME and PF groups were decreased by 13.6%

11.8%

respectively. Intestinal perfusion experiment showed that the transportation rate of DNJ was significantly different (P<0.05) between the two groups ME-PF and ME

with effective permeability (Peff) values of 3.5×10-3

7.5×10-3 cm·min-1

respectively. The percentage of transportation of DNJ were also significantly different (P<0.01)

with 14.8%

31.6%

respectively. Conclusion: PF could significantly improve the hypoglycemic effects of ME

for depress elevation of postprandial blood glucose

this may probably related with that PF could strongly decrease the absorption of DNJ in the small intestine

and resulting higher DNJ concentration in small intestine could display a relative stronger α-glycosidase inhibition activity.