Abstract

Baicalin, baicalein, wogonoside and wogonin are the major flavones of Radix scutellariae with various beneficial biological activities. The purpose of this study was to investigate the tissue distribution and compare the differences of these flavones after orally administrating the pure baicalin, R. scutellariae and Scutellariae-Paeoniae couple extracts with the same dose of 200 mg/kg baicalin. Tissue concentrations of baicalin, baicalein, wogonoside and wogonin were determined by high performance liquid chromatography (HPLC). Organ samples including the heart, liver, spleen, lung, kidney, large intestine, small intestine and stomach were collected at three specific times (15 min, 8 h, 24 h). Unpaired Student’s t-test was used for statistical comparison. The results indicated that the baicalin, wogonoside, baicalein and wogonin all occurred in the investigated tissues after orally administrating the pure  compound to the rats. Considerable concentrations of baicalein and wogonin could be detected in the investigated tissues, but were not found in rat serum. The contents of glycosides were higher than that of aglycones in small intestine, stomach, lung, heart and kidney; conversely in liver, large intestine and spleen. Pure baicalin was absorpted faster than R. scutellariae and Scutellariae-Paeoniae couple extracts. The concentrations of baicalin, baicalein, wogonoside and wogonin in the investigated tissues after orally administrating Scutellariae-Paeoniae couple extract (24 h) were higher (P＜0.05) than after orally administrating the pure baicalin and R. scutellariae extract.

Key words:  Baicalin, wogonoside, baicalein, wogoin, distribution, Scutellariae-Paeoniae.

Abbreviation

HPLC, High performance liquid chromatography; TCM, traditional Chinese medicine; RS, Radix scutellariae; IS, internal standard; HCl, hydrochloric acid; FDA, food and drug administration; QC, quality control; RE, relative error; RSD, relative standard deviation; LLOQ, lower limit of quantification; GUS, glucuronidase; LC-MS-MS, liquid chromatography-mass spectrometry.