Comparison of Urinary Kinetics between Traditional Decoction and Concentrated Powders of Puerariae Radix in Healthy Men
YU-CHI HOU1,4, PEI-DAWN LEE CHAO1, YI-ROU YEH2, SHIH-YING YANG3 AND SHANG-YUAN TSAI1*
1. School of Pharmacy, China Medical University, Taichung, Taiwan, R.O.C.
2. School of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan, R.O.C.
3. Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung, Taiwan, R.O.C.
4. Department of Medical Research, China Medical University Hospital, Taichung, Taiwan, R.O.C.
(Received: January 12, 2011; Accepted: July 12, 2011)
ABSTRACT
Puerariae Radix (PR), the roots of Pueraria lobata (Leguminosae), is widely used in clinical Chinese medicine and also as a food in oriental countries. PR is a rich source of isoflavones including puerarin, daidzin and daidzein. This study was aimed to compare the urinary kinetics of isoflavones between traditional decoction (TD) and concentrated powders (CP) of PR in healthy man. Ten male volunteers were given two dosage forms of PR in a crossover design and their urine was collected at specific intervals until 36 h. Urine samples were assayed by an HPLC method before and after hydrolysis with β-glucuronidase and sulfatase. The results indicated that the parent forms of puerarin, daidzin and daidzein were not detected in urine, whereas daidzein sulfates/glucuronides were predominant, mainly sulfates. The half-lives of daidzein sulfates/glucuronides were 5 - 7 h. In conclusion, the isoflavones were exclusively metabolized to sulfates/glucuronides of daidzein following administration of TD and CP of PR. Through the comparison of urine kinetics between two dosage forms, we suggest that the standardization of the contents of daidzin and daidzein, which are bioavailable, is more important than puerarin content for the efficacy of PR.
Key words: isoflavone, Pueraria lobata, puerarin, daidzin, daidzein, pharmacokinetics, metabolites