High Performance Liquid Chromatography (HPLC) Method for Determination of Isoflavones Content in Shade-Tolerant Soybean Dena I

Soybeans (Glycine max (L.) Merrill) are the most common source of isoflavones in human foods which useful for health as preventions of cardiovascular disease, cancer, diabetes, hypertension, osteoporosis, and menopause. The amount of isoflavones in soybeans may differ significantly depends on both genetic and environmental factors. Among the four forms of isoflavones, the highest biological activity is indicated by isoflavones aglycones i.e., genistein, daidzein, and glycitein. Genistein and daidzein found as major compounds with significant amounts contained in soybeans. Indonesian Legumes and Tuber Crops Research Institute (ILETRI) cultivate a shade-tolerant soybeans variety called Dena I to overcome the production of soybeans in Indonesia. Although finding exist for Dena I variety, there are no firm data regarding the isoflavones content of this variety. In this research, high performance liquid chromatography (HPLC) method using a C-18 column with UV detection in optimum condition was performed to identify and quantify the isoflavones content in the extract of Dena I soybean. The satisfied separation was obtained using the mobile phase of acetonitrile-acetic acid 0.1% with the gradual increase of acetonitrile 15-30%, the flow rate of 1 mL/min, and detection wavelength of 260 nm. Isoflavone genistein in Dena I extract was eluted at the retention time (tR) of 24.696 min, the same way with the retention time (tR) of standard genistein of 24.490 min. The concentration of genistein was found 0.0524 mg/g Dena I soybean.