Peptides from Pithecellobium dulce (guamúchil) and Inga jinicuil (jinicuil) proteins: In silico prediction and in vitro validation of their antioxidant and anti-inflammatory properties

Abstract

Underutilized legumes are a source of bioactive compounds, such as peptides with antioxidant properties that can prevent non-communicable diseases (NCDs) and be valorized in the food and health industries. This study aimed to evaluate, by in silico and in vitro approaches, the antioxidant and inflammatory potential of peptide fractions released during the simulated gastrointestinal digestion of Pithecellobium dulce (guamúchil, GM) and Inga jinicuil (jinicuil, JN) protein seeds. These seeds are obtained as natural by-products after the edible aril of the fruit is consumed. A proteomic analysis was conducted, evaluating the functionality of the identified legume proteins by the OmicsBox software. In addition, in silico tools (Rapid Peptide Generator, Peptide Ranker, AnoxPP, AnOxPePred 1.0, and PreAIP) were employed to simulate gastrointestinal digestion and estimate the antioxidant and anti-inflammatory properties of the released peptides. These approaches revealed that after the action of digestive enzymes on GM and JN proteins, 21 peptides with potential antioxidant and anti-inflammatory activity were released. These activities were attributed to their high content of hydrophobic, aromatic and positively charged amino acids. Biochemical and cell assays were used to determine selected bioactivities of the peptide fractions. High and low molecular peptide fractions exerted radical scavenging activity. The < 5 kDa fraction of JN significantly (p < 0.05) reduced the reactive oxygen species (ROS) levels under basal and stimulated conditions, and demonstrated anti-inflammatory effects by reducing tumor necrosis factor (TNF)-α levels in macrophages. These findings suggested that seeds of GM and JN could be a sustainable source of health promoting molecules.