Analysis and Comparison of Baicalin, Baicalein and Wogonin Contents in Traditional Decoctions and Commercial Extracts of Scutellariae Radix
MIAO-YING LAI1,2, CHUNG-CHUAN CHEN1, SU-LAN HSIU2 AND PEI-DAWN LEE CHAO2*
1. Institute of Chinese Pharmaceutical Sciences, China Medical College, Taichung, Taiwan, R.O.C.
2. Department of Pharmacy, China Medical College, Taichung, Taiwan, R.O.C. 91 Hsueh Shih Rd., Taichung, Taiwan 404, R.O.C.
Institute of Chinese Pharmaceutical Sciences, China Medical College, Taichung, Taiwan, R.O.C.Institute of Chinese Pharmaceutical Sciences, China Medical College, Taichung, Taiwan, R.O.C.
(Received: March 29, 2001; Accepted: July 13, 2001)
ABSTRACT
Baicalin, baicalein and wogonin are bioactive flavonoids of Scutellariae Radix. In order to compare the contents of baicalin, baicalein and wogonin between traditional decoction and commercial extract, ten crude drugs and ten commercial extracts of Scutellariae Radix were purchased from the market. High performance liquid chromatographic method was used for simultaneous assay of these flavonoid constituents. The separation was performed on an Inertsil ODS-2 column with acetonitrile -0.005% phosphoric acid (36:64, v/v) as mobile phase at a flow-rate of 1.0 mL/min and detection at 270 nm, and ethyl paraben was used as the internal standard. This method is applicable for the routine quality control of the crude drug and commercial extract of Scutellariae Radix.The results indicated that the contents of baicalin, baicalein and wogonin in traditional decoctions of each gram of Scutellariae Radix were 62.7±4.6 mg, 5.5±0.2 mg and 1.7±0.1 mg, whereas those in each gram of commercial extracts were 82.3±8.5 mg, 15.0±2.0 mg and 5.3±0.5 mg, respectively.
The suggested daily doses of crude drug and commercial extract of Scutellariae Radix are 3.0-9.0 g and 0.4-9.0 g, respectively. Based on our results, the contents of baicalin, baicalein and wogonin in the maximum daily doses for traditional decoctions of Scutellariae Radix were 564.7±41.7 mg, 49.7±1.9 mg and 15.6±1.0 mg, whereas those for commercial extracts were 241.9±41.1 mg, 53.7±16.4 mg and 17.9±4.6 mg, respectively.
Key words: Scutellariae Radix, baicalin, baicalein, wogonin, decoction, commercial extract