Chronic low-grade inflammation is present in overweight and obesity, causing changes in several metabolic pathways. It impairs systemic functioning and positively feeds back the accumulation of more adipose tissue. Studies with hydrolyzed proteins and plant peptides have demonstrated a potential anti-inflammatory and immunomodulatory effect of these peptides. However, it is challenging and necessary to explore the mechanism of action of such molecules because understanding their effects depends on their structural characterizations. Furthermore, the structure might also give insights into safety, efficacy and efficiency, with a view of a possible health application. Thus, the present narrative review aimed to discuss the mechanisms of action of hydrolyzed proteins and plant peptides as anti-inflammatory agents in obesity. Keywords and related terms were inserted into databases for the search. Based on the studies evaluated, these biomolecules act by different pathways, favoring the reduction of inflammatory cytokines and adipokines and the polarization of macrophages to the M2 phenotype. Finally, as a future perspective, bioinformatics is suggested as a tool to help understand and better use these molecules considering their applicability in pre-clinical and clinical studies.

Several studies have sought new therapies for obesity and liver diseases. This study investigated the effect of the trypsin inhibitor isolated from tamarind seeds (TTI), nanoencapsulated in chitosan and whey protein isolate (ECW), on the liver health status of the Wistar rats fed with a high glycemic index (HGLI) diet. The nanoformulations without TTI (CW) and ECW were obtained by nanoprecipitation technique, physically and chemically characterized, and then administered to the animals. The adult male Wistar rats (n = 20) were allocated to four groups: HGLI diet + water; standard diet + water; HGLI diet + ECW (12.5 mg/kg); and HGLI diet + CW (10.0 mg/kg), 1 mL per gagave, for ten days. They were evaluated using biochemical and hematological parameters, Fibrosis-4 Index for Liver Fibrosis (FIB-4), AST to Platelet Ratio Index (APRI) scores, and liver morphology. Both nanoparticles presented spherical shape, smooth surface, and nanometric size [120.7 nm (ECW) and 136.4 nm (CW)]. In animals, ECW reduced (p < 0.05) blood glucose (17%), glutamic oxalacetic transaminase (39%), and alkaline phosphatase (24%). Besides, ECW reduced (p < 0.05) APRI and FIB-4 scores and presented a better aspect of hepatic morphology. ECW promoted benefits over a liver injury caused by the HGLI diet.

The present study investigated the effect of gelatin-based nanoparticles (EPG) loaded with a carotenoid-rich crude extract (CE) on systemic and adipose tissue inflammatory response in a model with inflammation induced by a high glycemic index and high glycemic load diet (HGLI). Nanoparticles synthesized were characterized by different physical and chemical methods. The in vivo investigation evaluated Wistar rats (n = 20, 11 days, adult male with 21 weeks) subdivided into untreated (HGLI diet), conventional treatment (nutritionally adequate diet), treatment 1 (HGLI + crude extract (12.5 mg/kg)), and treatment 2 (HGLI + EPG (50 mg/kg)) groups. Dietary intake, caloric intake and efficiency, weight, inflammatory cytokines tissue concentration, visceral adipose tissue (VAT) weight, histopathological analysis, and antioxidant activity in plasma and VAT were investigated. EPG showed the same physical and chemical characteristics as previous batches (95.2 nm, smooth surface, and chemical interactions between materials). The EPG-treated group was the only group promoting negative ∆dietary intake, ∆caloric efficiency, and ∆weight. In addition, it presented a significant reduction (p < 0.05) in IL-6 and leptin levels and a greater presence of multilocular adipocytes. The results suggest that EPG can act as a nutraceutical in adjuvant therapy for treating inflammatory diseases associated with adipose tissue accumulation.