Metal ions can modify plant metabolism and change the level of biologically active components. In the present study, the impact of short-term exposure to strontium on the accumulation of the metal as well as the content of isoflavones in soybean sprouts was investigated.

The seeds were germinated in hydroponics with 0, 1, 1.5, 2.5, 5.0, or 10.0 mM of Sr for 72 hours. The content of strontium was assessed using flame atomic absorption spectrometry and the amount of isoflavones was determined with high performance liquid chromatography. Dose-dependent accumulation of Sr and a linear correlation between the Sr concentration in the growth medium and the content of the element in the plant samples were observed. The largest changes in the isoflavone content, compared to the control, were noted in soy sprouts germinated in the presence of 5 and 10 mM of strontium. Daidzin, genistin, malonyldaidzin, and malonylgenistin were the dominant isoflavones and their content increased by approx. 28, 44, 34, and 47%, respectively, compared to the control. Low amounts of aglycones were found; moreover, their content decreased by ca. 19–30%. Our research can be important for obtaining a natural product enhanced with strontium and isoflavones, which contribute to prevention of osteoporosis associated with endogenous oestrogen deficits.