Contribution of Proteins and Peptides to the Impact of a Soy Protein Isolate on Oxidative Stress and Inflammation-Associated Biomarkers in an Innate Immune Cell Model

Abstract

The innate and adaptative immune systems are involved in the regulation of inflammatory and oxidative processes and mediators such as reactive oxygen species (ROS) and nitric oxide (NO). The exacerbated action of these players results in an oxidative stress status and chronic inflammation, which is responsible for the development of non-communicable diseases (NCDs). By modulating these mediators, bioactive compounds in food can exert a key role in the prevention of several NCDs. Among these compounds, soybean proteins and peptides such as lunasin have been considered to be among the most promising. The aim of this study was to obtain and characterize a soluble protein-enriched extract from a commercial soybean protein isolate and fractionate it into different fractions through ultrafiltration. Their antioxidant and immunomodulatory properties were then evaluated using biochemical and cell models. A total of 535 proteins (from 282 protein groups) were identified in the extract, in which the presence of the peptide lunasin was confirmed. The enrichment of this peptide was achieved in the 3–10 kDa fraction. The protective effects against the oxidative stress induced by LPS in the macrophage model could have been mediated by the radical scavenging capacity of the peptides present in the soybean samples. Under basal conditions, the extract and its ultrafiltered fractions activated macrophages and induced the release of NO. However, under challenged conditions, the whole extract potentiated the NO-stimulating effects of LPS, whereas the fraction containing 3–10 kDa peptides, including lunasin, counteracted the LPS-induced NO increase. Our findings suggest a promising role of soybean protein as an ingredient for functional foods and nutraceuticals aimed at promoting health and preventing oxidative stress and/or immune-alteration-associated diseases.

Proteomic Characterization of a Lunasin-Enriched Soybean Extract Potentially Useful in the Treatment of <i>Helicobacter pylori </i>Infection

“…In Caco-2 cells, the antioxidant effect of this peptide was also demonstrated, reducing ROS levels in a dose-dependent manner, with a reduction of 62.7% at 25 µM [35]. Recently, we demonstrated that a soybean protein isolate reduced ROS generation in lipopolysaccharide (LPS)-challenged macrophages RAW264.7, being medium and low-molecular weight peptides the main responsible for the observed effects [36]. The discrepancies between these studies and our current results could be due to different factors such as the type of cell line used, the concentration of lunasin or antioxidant peptides present in LSE or the presence of other compounds in our extract that could antagonize the effect of lunasin and other antioxidant compounds [19,37].…”

Targeting Metabolic Diseases: The Role of Nutraceuticals in Modulating Oxidative Stress and Inflammation

“…The remarkable potential of nutraceuticals extends far beyond their actions; it resides in their unique ability to orchestrate a symphony of benefits, harmoniously targeting multiple intricate pathways implicated in oxidative stress and inflammation [ 80 , 81 , 82 ]. The advent of personalized medicine has introduced a highly promising avenue for optimizing nutraceutical therapy within the realm of these medical conditions [ 83 ].…”

Recovery, Characterization, Functionality and Applications of Bioactive Compounds from Food-Plant Products and Their By-Products

“…In terms of the functionality of bioactive components, this SI reported several interesting applications, with one of them being focused on proteins and peptides (the only paper in this Issue containing these bioactive compounds) derived from a soy protein isolate [14]. Soybean proteins and peptides, such as lunasin, have been considered promising bioactive compounds in the regulation of inflammatory and oxidative processes and mediators, such as reactive oxygen species (ROS) and nitric oxide (NO).…”