In vivo studies show the benefits of the trypsin inhibitor isolated from tamarind (Tamarindusindica L.) (TTI) seeds in satiety and obesity. In the present study, TTI nanoencapsulation (ECW) was performed to potentialize the effect of TTI and allow a controlled release in the stomach. The impact on glycemia, insulin, and lipid profile was evaluated in Wistar rats overfed with a high glycemic index diet (HGLI). Characterization of the nanoparticles and in vitro stability in simulated gastrointestinal conditions, monitored by antitrypsin activity and HPLC, was performed. ECW and empty nanoparticles (CW) were administered by gavage, using 12.5 and 10.0 mg/kg, respectively. Both nanoformulations presented a spherical shape and smooth surface, with an average diameter of 117.4 nm (24.1) for ECW and 123.9 nm (11.3) for CW. ECW maintained the antitrypsin activity (95.5%) in the gastric phase, while TTI was completely hydrolyzed. In Wistar rats, the nanoformulations significantly reduced glycemia and HOMA IR, and ECW increased HDL-c compared to CW (p < 0.05).Pancreas histopathology of animals treated with ECW suggested an onset of tissue repair. Thenanoencapsulation provided TTI protection, gradual release in the desired condition, and improvement of biochemical parameters related to carbohydrate metabolism disorders,without compromising insulinemia.

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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 study aimed to evaluate the nanoparticles (ECW) containing tamarind trypsin inhibitor (TTI) concerning the storage effect under different conditions on antitrypsin activity and the bioactive potential in a preclinical model. ECW was exposed to different pH and temperatures to evaluate the interaction between TTI and its encapsulating agents, monitored by antitrypsin activity. Wistar rats (n = 25) with obesity induced by diet were divided into groups: untreated; treatment with nutritionally adequate diet; treatment with nutritionally adequate diet and ECW/12.5 mg/kg; treatment with ECW/12.5 mg/kg; and treatment with TTI/25 mg/kg. The groups were evaluated over ten days with regards to satiety, zoometric, biochemical, and inflammatory parameters, using ten times less TTI (2.5 mg/kg) contained in ECW. TTI was protected and encapsulated in ECW without showing residual inhibitory activity. Only at gastric pH did ECW show antitrypsin activity. At different temperatures, it showed high antitrypsin activity, similar to TTI. The animals treated with ECW had significantly reduced body weight variation (p < 0.05), and only TTI treatment reduced the inflammatory parameters significantly (p < 0.05). The study showed that by using lower concentrations of TTI in ECW it was possible to perceive promising effects with perspectives of use in functional products for managing obesity and its complications.

Bacterial infections have become a global concern, stimulating the growing demand for natural and biologically safe therapeutic agents with antibacterial action. This study was evaluated the genotoxicity of the trypsin inhibitor isolated from tamarind seeds (TTI) and the antibacterial effect of TTI theoric model, number 56, and conformation number 287 (TTIp 56/287) and derived peptides in silico . TTI (0.3 and 0.6 mg.mL −1 ) did not cause genotoxicity in cells ( p > 0.05). In silico , a greater interaction of TTIp 56/287 with the Gram-positive membrane (GP) was observed, with an interaction potential energy (IPE) of −1094.97 kcal.mol −1 . In the TTIp 56/287-GP interaction, the Arginine, Threonine (Thr), and Lysine residues presented lower IPE. In molecular dynamics (MD), Peptidotrychyme59 (TVSQTPIDIPIGLPVR) showed an IPE of −518.08 kcal.mol −1 with the membrane of GP bacteria, and the Thr and Arginine residues showed the greater IPE. The results highlight new perspectives on TTI and its derived peptides antibacterial activity.

Caracterização físico-química de inibidor de tripsina isolado de sementes de tamarindo (Tamarindus indica l.) Nanoencapsuladoem proteína do leite isolada Physicochemical characterization of trypsin inhibitor isolated from tamarind seeds (Tamarindus indica l.) Nanoencapsulated in isolated milk protein

Introduction: Infectious diseases caused by bacteria represent one of the challenges in human healthcare, mostly caused by resistant bacteria, increasing the treatment cost, and fatal health complications. Researchers worldwide seek new therapeutic strategies to combat these highly resistant bacteria. Trypsin inhibitor peptides or proteins have innumerous bioactivities, such as antibacterial activity, which makes them potential candidates to treat diseases caused by bacteria. Thus, this study protocol describes a systematic review concerning the action mechanisms related to these molecules’ antibacterial activity. Methods: This systematic review protocol was elaborated according to the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P). The databases PubMed, ScienceDirect, Scopus, Web of Science, and Virtual Health Library will be used. Experimental studies carried out with rats and/or mice of both sexes, without water or diet restriction and in vitro (bacterial culture) studies and in cell, treated with trypsin inhibitor-type peptides or proteins that have a possible antibacterial action will be included. If at least two studies present clinical and/or methodological and/or statistical homogeneity, a meta-analysis will be carried out at the end of the analysis. The selection of studies, data extraction, and methodological quality assessment will be performed independently by two reviewers. Results: This protocol will be the basis for a systematic review. It is expected to identify several manuscripts highlighting the mechanisms related to the action of trypsin inhibitor peptides or proteins on bacteria. Conclusion: The systematic review based on this protocol will gather knowledge about trypsin inhibitor peptides or proteins’ antibacterial action mechanisms. It will provide subsidies for new research involving these molecules’ application against infectious diseases caused by bacteria. Ethics and dissemination: The present work does not involve any humans or animals; therefore, ethical approval is not needed. Prospero Registration Number: This review was registered with the International Register of Prospective Systematic Reviews on Jun 11, 2020 (registration: CRD42020189069). Available at: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=189069.