Charge properties of peptides derived from casein affect their bioavailability and cytoprotection against H2O2-induced oxidative stress

Abstract

The effects of charge properties of casein peptides on absorption stability, antioxidant activity, and cytoprotection were evaluated. Alcalase hydrolysates of casein were separated into 4 fractions by cation-exchange chromatography according to charge properties. After simulated digestion and Caco-2 cell transmembrane transport, we determined the total antioxidant capacity (Trolox equivalent antioxidative capacity and oxygen radical antioxidant activity) and nitrogen content of peptide fractions to estimate available antioxidant efficacy and bioavailability (BA) of peptides. Results showed that negatively charged peptide fractions had greater BA and antioxidant activities after digestion and absorption. The peptide permeates were used to test the cytoprotective effect against H2O2-induced oxidative damage in HepG-2 cells. All peptide permeates increased cell viability, elevated catalase activity, and decreased superoxide dismutase activity. However, negatively charged peptide fractions preserved cell viability to a greater degree. Therefore, the negatively charged peptides from casein may be potential antioxidants and could be used as ingredients in functional foods and dietary supplements.

Anti‐proliferative activity of bovine blood hydrolysates towards cancer cells in culture

“…hydrolysate used in this study has a negative charge. Negatively charged hydrolysates have been shown to have greater antioxidant activity compared to positively charged hydrolysates (Wang et al, 2016). Hydrophobic amino acids, such as valine and leucine, have also been shown to correlate with antioxidant activity (Power et al, 2013), and the presence of these amino acids in the structure of the fibrinogen hydrolysate, together with the probable negative charge, may be a contributing factor for the antioxidant activity seen in the present study.…”

“…Negatively charged hydrolysates have been shown to have greater antioxidant activity compared to positively charged hydrolysates (Wang et al, 2016). Negatively charged hydrolysates have been shown to have greater antioxidant activity compared to positively charged hydrolysates (Wang et al, 2016).…”

Immunomodulatory activity of 5 kDa permeate fractions of casein hydrolysates generated using a range of enzymes in Jurkat T cells and RAW264.7 macrophages

“…A follow-on study reported that the Alcalase® hydrolysis of casein produced hydrolysate fractions which enhanced catalase and superoxide dismutase activity and increased viability in H 2 O 2 -exposed HepG2 cells. The hydrolysate was fractionated based on charge and negatively charged fractions had greater antioxidant activity (Wang, Xie, & Li, 2016). Results herein indicate that the enzymes used did not affect antioxidant activity as hydrolysate 5 kDa permeates with similar activity were produced in all cases.…”

Current Evidence on the Bioavailability of Food Bioactive Peptides

“…In the field of bioactive peptides, over the past 10 years, a high number of studies have evaluated the absorption of these peptides and the mechanisms of transport across Caco-2 cell monolayers ( Table 2 ). Thus, the absorption of intact sequences across Caco-2 cells monolayers has been demonstrated for antioxidant peptides derived from soybean protein [ 140 ], corn gluten [ 141 ], milk proteins [ 89 , 142 , 143 ], and dry-cured Xuanwei ham [ 144 ], and for antihypertensive peptides derived from lactoferrin [ 145 ], ovotransferrin [ 114 ], and ovoalbumin [ 146 ]. Similarly, this model has been used to demonstrate the efficient transport of multifunctional soybean peptide lunasin or its derived fragment RKQLQGVN by paracellular diffusion [ 96 ], and of multifunctional peptides released from lupin storage proteins by digestive enzymes [ 147 ].…”