β-Conglycinins among Sources of Bioactives in Hydrolysates of Different Soybean Varieties That Inhibit Leukemia Cells in Vitro

Abstract

Soybean is a complex matrix containing several potentially bioactive components. The objective was to develop a statistical model to predict the in vitro anticancer potential of soybean varieties based on the correlation between protein composition and bioactive components after simulated gastrointestinal enzyme digestion with their effect on leukemia mouse cells. The IC 50 values of the hydrolysates of soy genotypes (NB1-NB7) on L1210 leukemia cells ranged from 3.5 to 6.2 mg/mL. Depending on genotype, each gram of soy hydrolysates contained 2.7-6.6 micromol of total daidzein, 3.0-4.7 micromol of total genistein, 0.5-1.3 micromol of glycitein, 2.1-2.8 micromol of total saponins, 0.1-0.2 micromol of lunasin, and 0.1-0.6 micromol of Bowman-Birk inhibitor (BBI). The IC 50 values calculated from a partial least-squares (PLS) analysis model correlated well with experimental data ( R (2) = 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 (IC 50 = 13.9 and 22.5 microM, respectively), but made modest contributions to the activity of defatted soy flour hydrolysates due to their relatively low concentrations. In conclusion, the data demonstrated that beta-conglycinins are among the major protein components that inhibit leukemia cell growth in vitro. Furthermore, it was feasible to differentiate soybean varieties on the basis of the biological effect of their components using a statistical model and a cell-based assay.

Soy, phytoestrogens and their impact on reproductive health

“…Some of the health benefits attributed to soy may result from the release of biologically active peptides by enzymatic proteolysis during gastrointestinal digestion or during the fermentation of soy proteins. For example, bioactive peptides encrypted in the amino acid sequence of soy proteins, in particular b-conglycinin, have been found to exert anticancer, antihypertensive, hypocholestorolemic, antiobesity and antioxidant activities (Martinez-Villaluenga et al, 2008, 2009Martinez-Villaluenga et al, 2010;Wang et al, 2008). Soybean also contains a wide range of micronutrients and phytochemicals including phytic acid (1.0-2.2%), sterols (0.23-0.46%), and saponins (0.17-6.16%), the effects of which have recently been reviewed in detail by Kang et al (2010).…”

Protein hydrolysates from β‐conglycinin enriched soybean genotypes inhibit lipid accumulation and inflammation in vitro

“…Protein DC assay (BioRad) was followed for protein quantification using BSA as standard (y = 0.0002x -0.0021, R 2 = 0.997). Pepsin-pancreatin hydrolysis (SGIH) of defatted soy flours in a way to simulate the in vivo enzyme hydrolysis was performed according to Wang et al [18]. All samples were stored at -808C until analysis.…”

“…Isoflavones and saponins concentrations were determined by extraction and quantification by HPLC as described previously in Wang et al [18]. Briefly, samples (typically 0.25 g) were placed in a vial and 3 mL of a DMSO/methanol (1:1) solution was added.…”

The soybean peptide lunasin promotes apoptosis of mammary epithelial cells via induction of tumor suppressor PTEN: similarities and distinct actions from soy isoflavone genistein

“…Soy foods contain bioactive components other than GEN that have been linked to cancer protection (Boué et al 2009;Wang et al 2008;Zhou et al 2002). Lunasin (LUN) is a 43-amino acid peptide component of post-translationally processed 2S albumin, initially identified in soybeans (Galvez and de Lumen 1999) and also present in barley, wheat and other seeds (Jeong et al 2007(Jeong et al , 2010Silva-Sanchez et al 2008).…”