Effect of Protein Hydrolysates from Germinated Soybean on Cancerous Cells of the Human Cervix: An In Vitro Study

Consumption of soybeans can reduce the risk of different types of cancer. Little is known about the effect of germination on the anticancer properties of soya. This study was done to determine if germination improves the anticancer properties of soybean protein through generation of amino acids or bioactive peptides. Soybean was germinated for 0, 2, 3, 4, 5, and 6 days and proteins were isolated from the seeds. Isolates with and without ethanol-soluble phytochemicals were hydrolyzed with digestive enzymes and their effect on growth in HeLa and C-33 (epidermoid cervical carcinoma) and HaCaT (non-cancerous human keratinocytes) cells were evaluated with the Alamar Blue method. Germination induced degradation of the alpha and alpha' fractions of beta-conglycinin and acid fraction of glycinin, generating low molecular weight peptides. Degrees of hydrolysis ranged from 73-77%. Hydrolysates inhibited the growth of HeLa cells and C-33 at concentrations exceeding 1.25 mg/ml. Major inhibition was observed with the hydrolysate germinated for 2 days and containing ethanolsoluble phytochemicals (IC50 2.15 and 2.27 mg/ml for HeLa and C-33, respectively). Interestingly, hydrolysate cytoxicity for normal cells was minimal in comparison to cancer cells.