RESUMO
Soybeans are an important source of bioactive molecules, such as peptides, which generation can improve through germination. In this study, the antioxidant and antiproliferative activities of three peptide fractions (>10 kDa, 5-10 kDa and <5 kDa) that were obtained by ultrafiltration of soybean protein hydrolysate after six days of germination were evaluated. The antioxidant activities of the peptide fractions were assessed by reducing power, Cu+2 and Fe+2 chelation and OH· scavenging assays, whereas their antiproliferative effects against cervical (HeLa, SiHa, CasKi) and breast (MCF7 and MDA-MB-231) cancer cell lines were evaluated by the MTT assay. Apoptosis was determined by Hoechst-PI staining. The most active peptide fraction (MAPF) was the >10 kDa fraction, which showed the greatest antioxidant and antiproliferative activity. The most sensitive cancer cell lines were the HeLa, CasKi and MDA-MB-231 cells, which had IC50 values of 16.2, 14.3 and 15.2 mg/mL, respectively, and apoptotic indices above 50 % after 6 or 8 h of exposure. The effect of MAPF on normal cells (HaCaT) was minimal. The amino acid composition of MAPF was characterized by high proline, phenylalanine and tyrosine content, and MALDI-TOF/TOF analysis showed six signals with molecular weights of 12 to 42 kDa.
