James A. Duke

Quantification of major isoflavonoids and l-canavanine in several organs of kudzu vine (Pueraria montana) and in starch samples derived from kudzu roots

Abstract Isoflavonoids (daidzein, genistein, daidzin, genistin and puerarin) were extracted and analyzed quantitatively by high pressure liquid chromatography from different organs of kudzu vine ( Pueraria montana ) and starch samples derived from kudzu roots. Aerial parts of kudzu plants (young shoots, leaf blades and leaf petioles) contained relatively low levels of all isoflavonoids examined, whereas seeds and seedlings were intermediate in isoflavonoid levels and roots consistently had the highest levels, particularly puerarin and the glucosyl conjugates of genistein and daidzein, namely, genistin and daidzin. Interestingly, commercially available kudzu root starch from Japan does not contain the isoflavonoids of interest, whereas homemade kudzu root starch contains all studied isoflavonoids in various amounts, and especially, high levels of puerarin. Shoots of light-grown kudzu seedlings, when compared with shoots of dark-grown seedlings had higher levels of all isoflavonoids with the exception of daidzin. In contrast, for seedling roots, such differences were not greatly different between light-grown and dark-grown plants. Light-grown intact kudzu seedlings had significantly higher levels of soluble proteins than dark-grown seedlings. Mass spectrometer analyzes of all kudzu samples for the toxic non-protein amino acid, l -canavanine, indicated it to be absent using this method of detection and level of sensitivity.

The production of L-dopa and isoflavones in seeds and seedlings of different cultivars of Vicia faba L. (fava bean)

The primary objective of this investigation is to compare the levels of L-dopa and the isoflavonoids, genistein and daidzein and their respective glucosyl conjugates, in seeds with ten-day-old seedlings of 24 different cultivars of fava bean (Vicia faba L.). Our working hypothesis is that the levels of these secondary metabolites will vary significantly in the different V. faba L. cultivars, and that seedlings will possess higher levels of both L-dopa and the isoflavonoids of interest than seeds of all of the cultivars used in this investigation. Here, we show that this hypothesis is correct. We discuss the importance of these findings for human medicine and nutrition, and their value for integrative medicine.