ABSTRACT
Radix puerariae (RP) is the root of Pueraria lobata Ohwi, a perennial plant of the Genus Pueraria. It is known as “Kakkon” in Japan and “Ge Gen” in China. In these countries, RP is an important herbal medicine used for antipyretic and antispasmodic purposes. Its major pharmacologically active components are isoflavonoid compounds such as daidzin, daidzein, puerarin, and genistein. Some pharmacokinetic data have been reported for daidzein (Su and Zhu, 1979), puerarin (Zhu et al., 1979), and genistein (Cayen et al., 1964); however, to date their metabolism, including the chemical structures of their metabolites, has not been studied in detail. Based on the study using genistein, Griffiths and Smith (1972) proposed a general mechanism for the in vivo biotransformation of isoflavonoids (Figure 13.1). However, the methods used so far have been largely paper chromatography and TLC which may not have sufficient sensitivity to detect all metabolites, especially the minor ones. Besides, only metabolites of isoflavone aglycones obtained from enzymatic hydrolysis were studied.
