An Insulin Receptor-Binding Multifunctional Protein from Tamarindus indica L. Presents a Hypoglycemic Effect in a Diet-Induced Type 2 Diabetes—Preclinical Study

Abstract

The objectives of this study were to evaluate the hypoglycemic effect of the trypsin inhibitor isolated from tamarind seeds (TTI) in an experimental model of T2DM and the in silico interaction between the conformational models of TTI 56/287 and the insulin receptor (IR). After inducing T2DM, 15 male Wistar rats were randomly allocated in three groups (n = 5): 1—T2DM group without treatment; 2—T2DM group treated with adequate diet; and 3—T2DM treated with TTI (25 mg/kg), for 10 days. Insulinemia and fasting glucose were analyzed, and the HOMA-IR and HOMA-β were calculated. The group of animals treated with TTI presented both lower fasting glucose concentrations (p = 0.0031) and lower HOMA-IR indexes (p = 0.0432), along with higher HOMA-β indexes (p = 0.0052), than the animals in the other groups. The in silico analyses showed that there was an interaction between TTIp 56/287 and IR with interaction potential energy (IPE) of −1591.54 kJ mol−1 (±234.90), being lower than that presented by insulin and IR: −894.98 kJ mol−1 (±32.16). In addition, the presence of amino acids, type of binding and place of interaction other than insulin were identified. This study revealed the hypoglycemic effect of a bioactive molecule of protein origin from Tamarind seeds in a preclinical model of T2DM. Furthermore, the in silico analysis allowed the prediction of its binding in the IR, raising a new perspective for explaining TTI’s action on the glycemic response.

Nanoparticles Containing Tamarind Isolate Protein Potentiate the Satiety without Promoting the Anti-Inflammatory Effect in a Preclinical Model of Diet-Induced Obesity

“…Queiroz et al [ 13 ] synthesized and characterized ECW, and, posteriorly, other preclinical studies were conducted with this nanoformulation using the same method of obtaining [ 14 , 15 , 16 ]. In the present study, TTI and ECW presented the same physicochemical characteristics and encapsulation efficiency, similar to previous studies [ 5 , 6 , 7 , 9 , 13 , 14 , 15 , 16 ]. Thus, it demonstrated the method’s reproducibility and guaranteed it was the same nanoparticle in question.…”

“…The fact that the presence of the inhibitor has activity at acidic pH is crucial since all the works with animals already carried out with these molecules, TTI or ECW, were administered by gavage, where the first contact was the stomach. Therefore, the presence of TTI, released from ECW, in this pH range would guarantee its proteolytic hydrolysis and, consequently, the absorption of its derived peptides and the systemic effects already attributed to it, whether on satiety, anti-inflammatory activity, or as a hypoglycemic agent [ 6 , 7 , 9 ].…”

“…Because of its potential, in several studies by the research group on Nutrição e Substâncias Bioativas Aplicadas à saúde (NutriSBioativoS) at UFRN, in Brazil, the effects of a trypsin inhibitor isolated from tamarind seeds, called TTI, have been evaluated in eutrophic and obese animals. Its role in satiety, improving metabolic parameters, and reducing inflammation has been demonstrated [ 5 , 6 , 7 , 8 , 9 ].…”

Anti-Inflammatory Protein Isolated from Tamarind Promotes Better Histological Aspects in the Intestine Regardless of the Improvement of Intestinal Permeability in a Preclinical Study of Diet-Induced Obesity

“…After confirmation of obesity, the animals were allocated to individual cages identified and randomly assigned to the following groups ( Figure 1 ): Group with HGLI diet and no treatment (n = 5), composed of animals with obesity induced by HGLI diet that, during the experimental period, continued to receive this diet and were not treated, receiving only 1 mL of water by gavage; Group treated with a nutritionally adequate diet (n = 5), composed of animals with obesity induced by the HGLI diet that, during the experiment, received the standard Labina ® diet + 1 mL of water by gavage; Group with HGLI diet and treated with TTI (n = 5), composed of animals with obesity induced by HGLI diet that, during the experiment, continued to receive this diet and were treated with 1 mL of TTI by gavage at a concentration of 25 mg/kg of body weight [ 27 , 41 ]. …”

“…Group with HGLI diet and treated with TTI (n = 5), composed of animals with obesity induced by HGLI diet that, during the experiment, continued to receive this diet and were treated with 1 mL of TTI by gavage at a concentration of 25 mg/kg of body weight [ 27 , 41 ].…”