Chemical constituents of Pueraria plants: identification and methods of analysis

The bioactivities of Pueraria plants can to a great extent be attributed to the presence of isoflavones and their glycosides. Kinjo et al. (1987), Ohshima et al. (1988), and Hirakura et al. (1997) separated a number of isoflavones by silica column chromatography including the well-known daidzein (1, Scheme 5.1), genistein (2), formononetin (3), and biochanin A (4), while these aglycones prevailed as well as glycosides having varying sugar moieties at different positions. Puerarin (5), the most abundant component, was first identified in Pueraria lobata, while daidzin (6) was originally detected in soybeans (Walz, 1931) and formononetin (3) is widely distributed in leguminous plants (Price and Fenwick, 1985).