Comparative pharmacokinetics of baicalin in normal and the type 2 diabetic rats after oral administration of the Radix scutellariae extract.

Radix scutellariaewas used alone or in combinationwith othermedicinal herbs in the treatment oftype 2 diabetes mellitus in China. At present, the pharmacokinetics of baicalin in type 2 diabeticrats following oral administration of Radix scutellariae extract was investigated. The resultsshowed that the pharmacokinetics (especially AUC) of baicalin in type 2 diabetic rats after oraladministration of Radix scutellariae extract was remarkably different from that in normal rats.Then the mechanism which resulted in the increased AUC of baicalin in diabetic rats wasinvestigated from system clearance and presystemic metabolism. And it was found that theincreased AUC of baicalin in diabetic rats at least partly resulted from higher production ofbaicalein in the intestinal tract of type 2 diabetic rats.Moreover, the activity of β-glucuronidase inintestinal mucosa of type 2 diabetic rats was demonstrated to be higher than that in normal rats,which confirmed the results above. In conclusion, the pharmacokinetic behavior of baicalin wassignificantly altered in type 2 diabetic rats after orally administrated Radix scutellariae extract,which may partly result from the increased activity of intestinal β-glucuronidase under thepathological state of type 2 diabetes mellitus.