Evaluation of Betanin on Key Enzymes Related to Obesity, Diabetes, Insulin Signaling Pathway, and Metabolic...

Background/Objectives: Betanin (Bet), a natural compound, exhibits potent antioxidant and metabolic regulatory properties, yet its effect on cellular glucose utilization remains unclear. This study investigated, for the first time, the impact of Bet on glucose consumption and the activation of key carbohydrate-catabolic pathways in human erythrocytes. Methods: In vitro assays were performed to evaluate enzyme inhibition and activation. Human erythrocytes were incubated with Bet to assess glucose consumption. Enzyme activities were measured spectrophotometrically, and molecular docking was used to analyze binding interactions. Results: Our results demonstrate that Bet inhibits digestive enzymes in a dose-dependent manner, with maximal inhibition at 90 µg/mL for pancreatic lipase and 70 µg/mL for α-amylase, showing IC₅₀ values of 48.8 and 31.9 µg/mL, respectively, supported by strong binding affinities of -9.3 and -8.9 Kcal/mol. These interactions are stronger than those of orlistat (-6.9 Kcal/mol) and acarbose (-7.7 Kcal/mol). Bet also induced the activity of AMPK with an IC₅₀ of 1.83 µg/mL and a BE of -7.90 Kcal/mol, compared to the specific AMPK activator A-769662, which had an IC₅₀ of 1.29 µg/mL and a binding energy of -10.0 Kcal/mol. Consequently, Bet stimulated key glycolytic enzymes, reaching maximal activation (~62%) at 1.4 µg/mL for hexokinase (HK) and glucose-6-phosphate dehydrogenase (G6PD), and at 1.6 µg/mL for pyruvate kinase (PK), supported by binding energies of -7.2, -7.5, and -9.0 Kcal/mol and AC₅₀ values of 0.87, 0.98, and 0.91 µg/mL, respectively. Moreover, Bet enhanced key Krebs cycle enzymes (IDH, SDH, MDH, LDH) in a dose-dependent manner, with AC₅₀ values of 0.76, 0.80, 0.72, and 0.52 µg/mL and strong binding energies (-7.8, -7.8, and -8.4 Kcal/mol), reaching maximal activation near 1.4 µg/mL. Bet also increased glucose consumption by human erythrocytes. Conclusions: Bet enhances glucose utilization by inhibiting digestive enzymes and activating intracellular metabolic pathways, suggest potential metabolic regulatory effects.