Anti-fatigue effects of fermented soybean protein peptides in mice.

BACKGROUND: Bioactive protein hydrolysates and peptides are believed to help counteract and ameliorate physical fatigue. Fermented soybean protein peptides (FSPPs) were prepared by protease hydrolysis and microbial fermentation. The present study aimed to evaluate the anti-fatigue properties of FSPPs. RESULTS: The forced swimming time in the FSPP group was 35.78% longer than the control group, the oxygen-resistant survival time of the FSPP group was significantly prolonged and the prolongation rate was 31.00%. In addition, FSPPs decreased the lactic acid (LD), blood urea nitrogen (BUN) and creatine kinase (CK) concentration by 27.47%, 25.93% and 21.70%, respectively, after treatment, while increasing the levels of liver glycogen and muscle glycogen by 93.35% and 67.31%, respectively. FSPPs can significantly increase gut microbiota diversity and regulate the species richness of gut microbiota. The results of real-time polymerase chain reaction (RT-PCR) and western blotting showed that FSPPs activate p-AMPK/PGC1-α and PI3K/Akt/mTOR signaling pathways. CONCLUSION: These results indicate that treatment with FSPPs induces anti-fatigue effects, which may be due to the mediating muscle protein synthesis and participation in skeletal muscle hypertrophy, providing energy for muscle cells. FSPPs may have potential applications in the food industry as functional material additives. © 2021 Society of Chemical Industry.

Pilot-scale production of soybean oligopeptides and antioxidant and antihypertensive effects in vitro and in vivo.

Soybean oligopeptides (SOP) with low molecular weights were prepared by two-step enzymatic hydrolysis on a pilot-scale. Peptide and free amino acid contents of SOP were 82.5 ± 1.13 % and 3.7 ± 0.28 % respectively. The molecular weight distribution of SOP was mainly bellow 1,000 Da (85.4 %), 56.7 % of which were 140-500 Da. SOP showed strong stability to proteolytic digestion by pepsin and trypsin. The antioxidant activities and in vitro and in vivo antihypertensive effects of SOP were evaluated. Results showed that SOP exhibited 1,1-diphenyl-2-picrylhydrazyl radical scavenging effect (IC50 = 4.5 ± 0.13 mg/mL), and significantly inhibited lipid peroxidation in linoleic acid oxidation system (IC50 = 1.2 ± 0.09 mg/mL). SOP had potent angiotensin I-converting enzyme inhibitory activity (IC50 = 1.1 ± 0.06 mg/mL), and antihypertensive effect in spontaneously hypertensive rats at a dose of 200 mg/kg. This study indicated that SOP could be a natural antioxidative or antihypertensive compound in the medicine and food industries.

One-week antihypertensive effect of Ile-Gln-Pro in spontaneously hypertensive rats.

The antihypertensive effect of an angiotensin I-converting enzyme (ACE) inhibitory peptide Ile-Gln-Pro (IQP), whose sequence was derived from Spirulina platensis , was investigated in spontaneously hypertensive rats (SHRs) for 1 week. The weighted systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the peptide IQP-treated group were significantly lower than those of the negative control group from the third and fourth days, respectively. Accompanying the blood pressure reduction, a significant regulation of the expression of major components of the renin-angiotensin system (RAS) was found in the treatment group, including downregulation of the mRNA levels of renin, ACE, and the angiotensin II type 1 (AT1) receptor in the kidney, as well as serum angiotensinogen (Ang), ACE, and angiotensin II (Ang II) concentrations. The treatment group also showed upregulation of mRNA expression of the angiotensin II type 2 (AT2) receptor in the kidney. Our findings suggested that IQP might be of potential use in the treatment of hypertension.