The immune system, inflammatory and oxidative processes are involved in the etiology and pathogenesis of a wide variety of chronic diseases with high morbidity and mortality rates worldwide1. Therefore, the development of new and alternative preventive and therapeutic strategies against infection, inflammation and oxidative stress is being explored. Regarding natural compounds, and especially among food-derived bioactive peptides, soybean lunasin has emerged as one of the most promising peptides with positive impact on health2.
A soybean extract enriched in lunasin (LES) was obtained and characterized, evaluating its behavior under simulated gastrointestinal conditions. Its radical scavenging capacity was evaluated by biochemical assays. Moreover, the antioxidant, anti-inflammatory, and immunomodulatory properties of LES were investigated in macrophages RAW 264.7, elucidating the potential mechanisms of action of lunasin. The effects on cell viability, phagocytic capacity, and levels of oxidative stress and inflammation-associated biomarkers were studied after different treatment times (8, 16, and 24 h) with different LES doses (0.5-15 µg protein/mL).
Our results showed, that after extraction with an aqueous solvent, an enrichment with soluble proteins and small peptides, such as lunasin, was achieved. After the simulated digestion, lunasin was detected at the end of the digestive process, indicating its partial resistance to the action of gastric and pancreatic enzymes. LES showed radical scavenging activity. Moreover, at low doses, LES reduced reactive oxygen species (ROS) levels in macrophages, while an oxidizing effect was observed at the highest concentration assayed. In addition, LES exerted an immunomodulatory action, with an increase in the production of nitric oxide (NO) in a dose- and time-dependent manner, and in the cellular phagocytic activity at short treatment times. The action of LES on cytokines secretion including both interleukin (IL)-6 and tumor necrosis factor (TNF)-α allowed confirming the modulatory effects of lunasin and other peptides contained in LES on the immune response.
References
(1) Furman, D. et al. (2019). Chronic inflammation in the etiology of disease across the life span. Nature Medicine, 25, 1822–1832.
(2) Fernández-Tomé, S. & Hernández-Ledesma, B. (2019). Current state of art after twenty years of the discovery of bioactive peptide lunasin. Food Research International, 116, 71-78.
