MOLECULAR DOCKING OF STEVIA POLYPHENOLIC FRACTIONS CONJUGATED WITH WHEY PROTEIN: TECHNO-FUNCTIONAL AND ANTIHYPERGLYCEMIC PROPERTIES

Protein conjugation with phenolics can improve physicochemical, techno-functional and biological properties. This pioneering study used a fraction of methanolic extract (F1) and ethanolic extract (F2) from Stevia to develop conjugates with whey proteins, using gallic acid and caffeic acid as controls. Stirring time and drying methods were used as variables. Six conjugates were formulated and tested: C1, C2, C3 (spray-dried), C4, C5 and C6 (lyophilized), being C1 and C4 with F1, C2 and C5 with F2 and C3 and C6 as controls.C3 presented the highest concentration of free phenolics. UHPLC-MS/MS was used to quantify and identify phenolics in F1 and F2. The antioxidant activity was tested for DPPH and ABTS+ radicals. The atomized ones had lower IC50, with higher activity of C3. In the antihyperglycemic activity (alpha-amylase), C4 showed the best result (51% inhibition). All products were more soluble than the fractions, while the atomized ones were more soluble than the isolated whey protein, with emphasis on C1, five times more soluble than the supplement and 17 times more than F1. Caffeic acid, chlorogenic acid and quercetin were selected for molecular docking with human pancreatic alpha-amylase PDB: 3OLI, in relation to the inhibitor acarbose and PDB ID: 4GQR, in relation to myricetin, using the GOLD 2024.1 and AutoDock Vina programs for simulations. The conformations with the highest scores were analyzed. In the first, caffeic acid showed greater affinity, while in the second test, quercetin showed greater affinity with the active site of the enzyme, with caffeic acid potentially acting on allosteric sites of the enzyme. This may be related to the inhibition observed in the conjugate with fraction 1, which contains these compounds mainly and in higher concentration than in F2. High solubility combined with better antidiabetic effects are promising results that may contribute to a potential adjuvant for diabetes.