Comparison of isoflavone yields and profiles from hairy root‐induced kudzu genotypes

Kudzu is a rich source of isoflavones, including puerarin which has positive effects on bone formation in vitro and in vivo, and may reduce bone loss associated with osteoporosis. Kudzu 14 C‐labeled isoflavones provide a means of studying their distribution and metabolic fate in vivo. In a recent pharmacokinetic trial, Sprague‐Dawley rats were gavaged using a crude extract containing P. lobata 14 C‐isoflavones. Appreciable levels of radiolabel (0.42, 0.33, and 0.10% of the administered dose) were detected in femur, tibia, and vertebrae, respectively. In the current study, hairy roots of 4 kudzu selections, Pueraria montana var. lobata (USA), P. montana var. lobata (Japan), P. lobata (USA), and P. phaseoloides (Guatemala) were extracted with 80% methanol to determine isoflavone content. Extracts were evaluated by high‐performance liquid chromatography (HPLC) with puerarin, daidzin, daidzein, malonyl‐daidzin, genistin, genistein, and malonyl‐genistin standards. P. montana var. lobata (USA) contained the highest puerarin and total isoflavone content of the 4 selections, with concentrations of 53.4 and 112.4 mg/g dry extract respectively. This strain is under cultivation to enhance isoflavone yields and facilitate further radiolabel‐assisted pharmacokinetic studies. Supported by NIH, 2 P50 AT000477 –06.