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Apart from nutrients required for the brain, there has been no report that naturally occurring peptides can cross the blood-brain barrier (BBB). The aim of this study was to identify the BBB-transportable peptides using in situ mouse perfusion experiments. Based on the structural features of Gly- N -methylated Gly (Gly-Sar), a reported BBB-transportable compound, 18 dipeptides were synthesized, and were perfused in the mouse brain for two minutes. Among the synthesized dipeptides, Gly-Sar, Gly-Pro, and Tyr-Pro were transported across the BBB with K i values of 7.60 ± 1.29, 3.49 ± 0.66, and 3.53 ± 0.74 µL/g·min, respectively, and accumulated in the mouse brain parenchyma. Additionally, using MALDI-MS/MS imaging analysis of Tyr-Pro-perfused brain, we provide evidence for Tyr-Pro accumulation in the hippocampus, hypothalamus, striatum, cerebral cortex, and cerebellum of mouse brain.

In this study, we compared the intestinal absorption from di#erent sources with the same amino acid composition (protein, peptide, and amino acid mixture) by measuring changes in serum concentrations of various amino acids. Peptides used in this study were prepared by enzymatic digestion of ++S globulin (a major component of soy protein). Twelve normal male adults were asked to drink beverages containing +,./ g of the test sample, representing /ῌ suspension of each of the following three di#erent preparations : ++S globulin, ++S peptide, and an amino acid mixture of equivalent composition. Venous blood samples were collected from * to +2* min to measure free amino acid concentrations. The early slope of serum concentrations and values of area under the curves for each amino acid calculated from changes in serum amino acid concentrations were significantly greater for ++S peptide than for either ++S globulin or the amino acid mixture. This trend was especially remarkable for branched-chain amino acids and aromatic amino acids. Our results suggest that the ingestion of hydrolyzed soy protein results in faster and more e$cient absorption than the consumption of protein or amino acid mixtures in healthy adult men.

PurposeThis study compared the effects of a combination of soy peptide supplementation and exercise with those of exercise only, on the cognitive function of elderly adults.Patients and methodsThis randomized, non-blinded, controlled clinical trial included 67 participants aged 60 years or more with non-cognitive dysfunction who were divided into two groups according to the intervention method: an exercise group (Ex group, n = 36) and an exercise plus nutrition group (Ex+Nt group, n = 31). The Ex group completed a memory training activity for 15 mins and aerobic exercise for 45 mins once a week for 90 days. The Ex+Nt group completed the same training plus received soy peptide for 90 days. The Mini-Mental Status Examination score, trail-making test A/B score, skeletal muscle mass index, grip strength, gait speed, and geriatric depression scale were measured at baseline and post intervention. For comparison between the pretest and posttest measurements to determine the intervention effects, a two-way analysis of variance was performed. The significance level was set at < 5%.ResultsA two-way analysis of variance revealed significant time effects on trail-making test-A score, skeletal muscle index, grip strength, and gait speed in both groups. There were significant time x group interactions for greater increase in calculation score.ConclusionA combination of exercise and soy peptide supplementation was effective in improving a portion of cognitive function.