Purification of novel antioxidant peptides from myofibrillar protein hydrolysate of chicken breast and their antioxidant potential in chemical and H2O2-stressed cell systems

Advances in Research on the Activity Evaluation, Mechanism and Structure-Activity Relationships of Natural Antioxidant Peptides

Antioxidant peptides are a class of biologically active peptides with low molecular weights and stable antioxidant properties that are isolated from proteins. In this review, the progress in research on the activity evaluation, action mechanism, and structure-activity relationships of natural antioxidant peptides are summarized. The methods used to evaluate antioxidant activity are mainly classified into three categories: in vitro chemical, in vitro cellular, and in vivo animal methods. Also, the biological effects produced by these three methods are listed: the scavenging of free radicals, chelation of metal ions, inhibition of lipid peroxidation, inhibition of oxidative enzyme activities, and activation of antioxidant enzymes and non-enzymatic systems. The antioxidant effects of natural peptides primarily consist of the regulation of redox signaling pathways, which includes activation of the Nrf2 pathway and the inhibition of the NF-κB pathway. The structure-activity relationships of the antioxidant peptides are investigated, including the effects of peptide molecular weight, amino acid composition and sequence, and secondary structure on antioxidant activity. In addition, four computer-assisted methods (molecular docking, molecular dynamics simulation, quantum chemical calculations, and the determination of quantitative structure-activity relationships) for analyzing the structure-activity effects of natural peptides are summarized. Thus, this review lays a theoretical foundation for the development of new antioxidants, nutraceuticals, and cosmetics.

Antioxidant peptides generated from chicken feet protein hydrolysates

BACKGROUND

As major industrial poultry by-products, chicken feet are considered as notable sources of several bioactive molecules. The current work covers the processing of chicken feet proteins as substrates to be hydrolysed by combinations of three commercial enzymes (Alcalase®, Flavourzyme® and Protana® Prime) during different hydrolysis periods and the evaluation of the identified peptides having antioxidant activity after simulated gastrointestinal digestion.

RESULTS

Enzymatic hydrolysis with Alcalase® and Protana® Prime combination for 4 h resulted in the highest activities. Reversed-phase high-performance liquid chromatographic separation of the purified hydrolysate yielded three active fractions that were further identified by nano-liquid chromatography-tandem mass spectrometry. The bioactivities of over 230 identified peptide sequences were estimated after simulated gastrointestinal digestion, and those peptides with the highest chance of exerting antioxidant activity were selected to be further synthesised and tested. In this sense, the synthesised dipeptides CF and GY showed the highest antioxidant capacity. CF presented IC50 values of 69.63 and 145.41 μmol L-1 in 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and oxygen radical absorbance capacity (ORAC) assays, respectively. In contrast, GY IC50 values were 15.27 and 10.06 μmol L-1 in ABTS and ORAC assays, respectively. Significant differences (P < 0.05) were registered between peptides in the same antioxidant assays.

CONCLUSION

Overall, the findings emphasised the favourable impact of enzymatic hydrolysis with the obtaining of antioxidant peptides from poultry by-products that could be evaluated as a safe and economical source to retard oxidation in food systems. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Transepithelial transport and cellular mechanisms of food-derived antioxidant peptides

Considering the involvement of oxidative stress in the etiology of many non-communicable diseases, food-derived antioxidant peptides (FDAPs) are strong candidates for nutraceutical development for disease prevention and management. This paper reviews current evidence on the transepithelial transport and cellular mechanisms of antioxidant activities of FDAPs. Several FDAPs have multiple health benefits such as anti-inflammatory and anti-photoaging activities, in addition to antioxidant properties through which they protect cellular components from oxidative damage. Some FDAPs have been shown to permeate the intestinal epithelium, which could facilitate their bioavailability and physiological bioactivities. Molecular mechanisms of FDAPs include suppression of oxidative stress as evidenced by reduction in intracellular reactive oxygen species production, lipid peroxidation and apoptotic protein activation as well as increase in antioxidant defense mechanisms (enzymatic and non-enzymatic). Since many FDAPs have demonstrated promising antioxidant activity, future investigation should focus on further elucidation of molecular mechanisms and human studies to explore their practical application for the prevention and management of oxidative stress-related diseases.