ARS | Publication request: Beta-conglycinins among sources of bioactives in soybean hydrolysates that inhibited leukemia cells in vitro

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 20, 2008
Publication Date: May 13, 2008
Citation: Wang, W., Bringe, N.A., Berhow, M.A., Gonzales De Mejia, E. 2008. Beta-conglycinins among sources of bioactives in soybean hydrolysates that inhibited leukemia cells in vitro. Journal of Agricultural and Food Chemistry. 56(11):4012-4020.

Interpretive Summary: Soy contains a complex mixture of chemical compounds, some of which may function to prevent certain types of cancer. The objective of this work was to build a statistical model that can be used to predict the anticancer potential of specific compounds in soy converted in a simulated digestion experiment on cultured cancer cells. The potential anticancer compounds were quantitated in the hydrolysates: the isoflavones, the saponins, the soy proteins lunasin, Bowman-Burke inhibitor (BBI), and conglycinin. Isoflavones and conglycinin positively contributed to the toxicity of soy on cancer cells. Lunasin and BBI were potent cancer cell growth inhibitors. This work shows that the protein matrix, as well as the discrete soy phytochemicals, makes an important contribution to the in vitro anticancer potential of soy.

Technical Abstract: Soybean is a complex matrix containing several potentially bioactive components. The objective was to build a statistical model to predict the anticancer potential of soybean based on the composition of bioactive components in soybean hydrolysates produced by simulated gastrointestinal digestion. The IC50 values of the hydrolysates of soy genotypes (NB1 - NB7) on L1210 leukemia cells ranged from 3.5 - 6.2 mg/mL. Depending on genotype, each gram of soy hydrolysates contained 2.7 - 6.6 mmol of total daidzein, 3.0 - 4.7 mmol of total genistein, 0.5 - 1.3 mmol of glycitein, 2.1 ¿ 2.8 umol of total saponins, 0.1 - 0.2 mmol of lunasin and 0.1 - 0.6 mmol of Bowman Birk inhibitor (BBI). The IC50 values calculated from a Partial Least Square (PLS) analysis model correlated well with experimental data (R2 = 0.99). Isoflavones and beta-conglycinin positively contributed to the cytotoxicity of soy on L1210 leukemia cells. Lunasin and BBI were potent L1210 cell inhibitors (IC50 13.9 and 22.5 mM, respectively), but making modest contributions to the activity of NBHs due to their relatively low concentrations. In conclusion, the composition of matrix protein had an important contribution to the in vitro anticancer potential of soy hydrolysates.