Anti-Diabetic Activity of Whey Proteins

Absract. Introduction. With the advent of membrane filtration technologies, milk whey stopped being a “by-product” of cheese, cottage cheese, and casein production. The combination of various whey-processing technologies, e.g. enzymatic hydrolysis and membrane fractionation, made it possible to obtain concentrates, isolates, and hydrolysates of whey proteins with various biologically active effects. Study objects and methods. The article features research results of Russian and foreign scientific teams in the development of functional antidiabetic ingredients from hydrolyzed proteins of milk and whey. Results and discussion. According to foreign studies, Ile-Pro-Ile (diprotin A) with an IC50 value of 4.7 μM is one of the most effective low molecular mass peptides with an inhibitory potential against DPP-IV. Various studies of trypsin hydrolysis of β-lactoglobulin described the production of IPAVF peptide fragment with the most potent inhibitory activity of DPP-IV (IC50 = 44.7 μM). Other studies featured pepsin-treated lactoglobulin production of fragments LKPTPEGDL and LKPTPEGDLEIL with inhibitory activity DPP-IV IC50 = 45 and 57 μM, respectively. A number of studies described similar fragments obtained by the sequential action of the enzyme preparation Neutrase 0.8 LTM on β-lactoglobulin, followed by pepsin hydrolysis. As for the hydrolysis of α-lactalbumin with pepsin, scientists identified peptides WLAHKALCSEKLDQ, LAHKALCSEKL, and TKCEVFRE. They revealed a high inhibitory potential against DPP-IV (IC50 = 141, 165, and 166 μM, respectively). Tryptic hydrolysates of bovine β-lactoglobulin proved to be able to inhibit DPP-IV in vitro (IC50 of 210 μM). Peptide VAGTWY was the major compound responsible for this effect, displaying an IC50 of 174 μM. In other research, tryptic hydrolysate inhibited DPP-IV with an IC50 value of 1.6 mg/mL, also demonstrating antioxidant and ACE-inhibitory activities. This hydrolysate became source of VAGTWY, the most potent DPP-IV inhibitor (IC50 of 74.9 μM). Conclusion. An analysis of Russian and foreign studies proved that milk protein hydrolysis has a great potential for antidiabetic additives used in the treatment of type II diabetes. This are requires further research in order to define the safety of biologically active peptides.