CASHEW NUT PROTEIN CONCENTRATE EXHIBITS ANTIHYPERGLYCEMIC EFFECTS THROUGH INHIBITION OF α-GLUCOSIDASE, α-AMYLASE AND IMPROVES ORAL GLUCOSE TOLERANCE IN C57BL/6 MICE

Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic condition associated with insulin resistance and hyperglycemia, the management of which may involve the inhibition of digestive enzymes, such as α-amylase and α-glucosidase. Peptides derived from dietary proteins can inhibit these enzymes, exhibiting antiglycemic potential. In this context, the cashew nut kernel (CNK) stands out as a plant-based protein source with technological, chemical, and nutritional potential that remains largely unexplored. Thus, the objective of this study was to obtain, characterize, and investigate the antiglycemic potential of the protein concentrate derived from CNK in the management of T2DM. The CNK was partially defatted by aqueous extraction, yielding the partially defatted cake (PDC), from which the CNK protein concentrate (PC) was obtained after isoelectric precipitation. PC underwent physicochemical (percentage composition) and structural (color, zeta potential, FTIR) characterization using standardized methods. In vitro biological activity was assessed by the inhibition of α-glycosidase and α-amylase enzymes and by cell viability (resazurin assay) in C2C12 cells. Finally, the in vivo antihyperglycemic effect was determined using the Glucose Tolerance Test (GTT) in C57BL/6 mice and the area under the glycemic curve (AUC) was analyzed. PC contained 66.10% protein, 24.05% lipids, 3.28% ash, 3.24% moisture, and 3.33% carbohydrates, calculated by difference, with a yield of 13.00% and a protein recovery rate of 27.99%. The increase in protein content from 30.70% (PDC) to 66.10% (PC) demonstrates the process’s efficiency in concentrating protein. The powder, which is light in color and slightly yellowish (L* = 77.31; b* = 16.19), is suitable for use in food and beverages. The zeta potential (-40.3 ± 3.77 mV, pH 7.21) indicates high colloidal stability due to the dense negative surface charge, which prevents aggregation and promotes solubility. FTIR confirmed the protein matrix, highlighting the Amide I (1,652 cm⁻¹) and Amide II (1,543 cm⁻¹) bands, as well as residual lipids (2,924, 2,853, and 1,745 cm⁻¹). CPACC inhibited α-glucosidase (IC₅₀ = 536.3 µg·mL⁻¹) and α-amylase (IC₅₀ = 718.25 µg·mL⁻¹), achieving over 50% inhibition at 1000 µg·mL⁻¹, demonstrating significant biological activity of the crude protein matrix and suggesting a dual mechanism for delaying carbohydrate absorption. In cytotoxicity assays using C2C12 cells, cell viability was maintained at concentrations up to 500 µg·mL⁻¹ at 24, 48, and 72 hours, indicating a favorable cellular safety profile. In vivo, CPACC improved the glycemic response in the GTT at a dose of 500 mg/kg and reduced the area under the glycemic curve (AUC) by 24.04%, confirming its acute antihyperglycemic effect. Therefore, the study concluded that PC has technological and antiglycemic potential, capable of inhibiting digestive enzymes and improving the glycemic response, representing a promising alternative for the management of T2DM. Acknowledgments to CNPq (444421/2014-6,404293/2023-9, 304143/2025-1), Embrapa and UFC.