Comparative pharmacokinetic and tissue distribution study of baicalin, baicalein, wogonoside, wogonin and oroxylin-A after oral administration of Component compatibility of SHT and total flavonoids fractions of Radix scutellariae to rats

Abstract

Sanwu-Huangqin-Tang (SHT) is a classical prescription used for treatment of gynecological disease, and its key ingredient is Radix scutellariae (Scutellaria baicalensis Georgi, Labiatae). Baicalin, wogonoside, baicalein, wogonin and oroxylin-A are five main effective ingredients enriched in Radix scutellariae. In the present study, pharmacokinetic and tissue distribution difference of the five compounds following oral administration of Component Compatibility of Sanwu-Huangqin-Tang (CCSHT) and total flavonoids fractions of Radix scutellariae (FSR) were investigated in male Sprague-Dawley rats with approximately the same dose. The amount of flavonoids in plasma and tissues were measured by a rapid and sensitive HPLC-MS/MS method. Unpaired Student's-test was used for statistical comparison. The bimodal phenomenon was observed in plasma profile after oral administration of FSR and CCSHT. Statistical significant increase (P < 0.05) in pharmacokinetic parameters (including C_max and AUC_0→t) and tissue distribution of the target compounds were observed after oral administration CCSHT comparing with FSR, but there were no significant differences between the two groups in parameters of T_max. The results indicated that compared with FSR, the bioavailability and distribution amount of flavonoids could be greatly improved by co-administrating alkaloids in Radix sophorae flavescentis and polysaccharide in Radix Scutellariae.