Cytotoxic and antioxidant capacity of camel milk peptides: Effects of isolated peptide on superoxide dismutase and catalase gene expression

Abstract

Peptides from natural sources such as milk are shown to have a wide spectrum of biological activities. In this study, three peptides with antioxidant capacity were identified from camel milk protein hydrolysate. Pepsin and pancreatin were used for hydrolysis of milk proteins. Ultrafiltration and reverse-phase high-performance liquid chromatography were used for the concentration and purification of the hydrolysate, respectively. Sequences of the three peptides, which were determined by matrix-assisted laser desorption/ionization time-of-flight spectrophotometry, were LEEQQQTEDEQQDQL [molecular weight (MW): 1860.85 Da, LL-15], YLEELHRLNAGY (MW: 1477.63 Da, YY-11), and RGLHPVPQ (MW: 903.04 Da, RQ-8). The 3-(4,5-dimethylthia-zol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate the cytotoxicity of these chemically synthesized peptides against HepG2 cells. In vitro analysis showed antioxidant properties and radical scavenging activities of these peptides on 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)+, O, and OH free radicals. HepG2 cells were treated with YY-11 peptide for 48 hours, and the expression of superoxide dismutase and catalase genes was examined using real-time polymerase chain reaction. The results revealed a significant increase in the expression of superoxide dismutase and catalase genes in treated HepG2 cells.

Inhibitory properties of camel whey protein hydrolysates toward liver cancer cells, dipeptidyl peptidase-IV, and inflammation

“…In both P3 and P6, the maximum inhibitory effect was observed with 1,000 µg/mL protein hydrolysate compared with untreated cells and cells treated with <400 µg/mL CWPH (Figure 5a and b; P < 0.05). These results are in agreement with studies that have found that pepsin-generated camel milk peptides were effective in reducing viability of HepG2 liver cancer cells (Homayouni-Tabrizi et al, 2017). Similarly, cells targeted with C3 CWPH showed significant reduction in viability compared with the untreated cells (Figure 5c).…”

“…For T6 CWPH, the antiproliferative effect against HepG2 cells was found with 60 to 80% of viable cells remaining when CWPH were applied at a concentration range of 50 to 1,000 µg/mL (Figure 5f). Antiproliferative activity could be related to generation of specific peptides exerting a direct cytotoxic effect on cancer cells, as previously reported for a protein hydrolysate able to induce apoptosis in cancer cells (Homayouni-Tabrizi et al, 2017). Previous reports have mostly focused on whey protein hydrolysates from milks other than camel.…”

A comprehensive review on bioactive peptides derived from milk and milk products of minor dairy species

“…Antioxidant peptides Hydrolysis of camel milk using pepsin-pancreatin enzymes yielded peptides with antioxidant and anti-cytotoxic activity (Homayouni-Tabrizi et al 2017). Concentration and purification of the peptides were achieved through ultrafiltration and reverse phase liquid chromatography, respectively.…”

Bioactive peptides as natural antioxidants in food products – A review

“…Peptides can exert antioxidant activity by the same mechanisms as those observed for other antioxidants. The exploration of antioxidant peptides requires additional technologies to release active amino acid sequences from proteins since the precursor proteins may not display the same antioxidant effect (Chi et al, 2014;Gallego, Mora, Hayes, Reig, & Toldrá, 2017;Homayouni-Tabrizi, Asoodeh, & Soltani, 2017;Jemil et al, 2016;Rizzello et al, 2017;Sachindra & Bhaskar, 2008).…”