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Screening of soy protein-derived hypotriglyceridemic di-peptides in vitro and in vivo.

Inoue N, Nagao K, Sakata K, Yamano N, Gunawardena PE, Han SY, Matsui T, Nakamori T, Furuta H, Takamatsu K, Yanagita T - Lipids Health Dis (2011)

Bottom Line: In the third experiment, we found that Fraction-C (Frc-C) peptides, fractionated from hydrophilic peptides by gel permeation chromatography-high performance liquid chromatography, significantly reduced TG synthesis and apolipoprotein B (apoB) secretion in HepG2 cells.In the fourth experiment, we found that the fraction with 0.1% trifluoroacetic acid, isolated from Frc-C peptides by octadecylsilyl column chromatography, showed hypolipidemic effects in HepG2 cells.In the final experiment, we found that 3 di-peptides, Lys-Ala, Val-Lys, and Ser-Tyr, reduced TG synthesis, and Ser-Tyr additionally reduced apoB secretion in HepG2 cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Applied Biochemistry and Food Science, Saga University, Saga 840-8502, Japan.

ABSTRACT

Background: Soy protein and soy peptides have attracted considerable attention because of their potentially beneficial biological properties, including antihypertensive, anticarcinogenic, and hypolipidemic effects. Although soy protein isolate contains several bioactive peptides that have distinct physiological activities in lipid metabolism, it is not clear which peptide sequences are responsible for the triglyceride (TG)-lowering effects. In the present study, we investigated the effects of soy protein-derived peptides on lipid metabolism, especially TG metabolism, in HepG2 cells and obese Otsuka Long-Evans Tokushima fatty (OLETF) rats.

Results: In the first experiment, we found that soy crude peptide (SCP)-LD3, which was prepared by hydrolyze of soy protein isolate with endo-type protease, showed hypolipidemic effects in HepG2 cells and OLETF rats. In the second experiment, we found that hydrophilic fraction, separated from SCP-LD3 with hydrophobic synthetic absorbent, revealed lipid-lowering effects in HepG2 cells and OLETF rats. In the third experiment, we found that Fraction-C (Frc-C) peptides, fractionated from hydrophilic peptides by gel permeation chromatography-high performance liquid chromatography, significantly reduced TG synthesis and apolipoprotein B (apoB) secretion in HepG2 cells. In the fourth experiment, we found that the fraction with 0.1% trifluoroacetic acid, isolated from Frc-C peptides by octadecylsilyl column chromatography, showed hypolipidemic effects in HepG2 cells. In the final experiment, we found that 3 di-peptides, Lys-Ala, Val-Lys, and Ser-Tyr, reduced TG synthesis, and Ser-Tyr additionally reduced apoB secretion in HepG2 cells.

Conclusion: Novel active peptides with TG-lowering effects from soy protein have been isolated.

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Related in: MedlinePlus

Effects of soy crude peptide (SCP)-LD3 on triglyceride (TG) synthesis in HepG2 cells (1 mg/mL) and hepatic TG level in Otsuka Long-Evans Tokushima fatty (OLETF) rats. Values are expressed as mean ± standard error of 5 samples in vitro and 6 rats in vivo. Asterisks indicate a significant difference at P < 0.05.
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Figure 3: Effects of soy crude peptide (SCP)-LD3 on triglyceride (TG) synthesis in HepG2 cells (1 mg/mL) and hepatic TG level in Otsuka Long-Evans Tokushima fatty (OLETF) rats. Values are expressed as mean ± standard error of 5 samples in vitro and 6 rats in vivo. Asterisks indicate a significant difference at P < 0.05.

Mentions: In the first part of the current study, we evaluated the effects of SCP-LD3 treatment on TG synthesis in HepG2 cells. As shown in Figure 3A, incorporation of [1-14C] acetate into the cellular TG fraction was significantly lowered by SCP-LD3 treatment. These results suggest that SCP-LD3 has the ability to normalize lipid abnormalities possibly through the suppression of TG synthesis in hepatocytes. Next, we evaluated the effects of SCP-LD3 on lipid metabolism in OLETF rats. As shown in Figure 3B, 2-week feeding of SCP-LD3 alleviated the obesity-induced TG accumulation in the liver of OLETF rats without significant alterations in other growth parameters such as food intake (control, 29.2 ± 0.6 g/day; SCP-LD3, 29.0 ± 0.6 g/day) and final body weight (control, 539 ± 12 g; SCP-LD3, 531 ± 17 g). Additionally, serum TG level was also lowered by SCP-LD3 feeding in OLETF rats (control, 251 ± 40 mg/dL; SCP-LD3, 143 ± 21 mg/dL, P < 0.05). These results indicate that SCP-LD3 has TG-lowering properties, which led us to perform further isolation and identification of hypolipidemic peptide sequences from this peptide during subsequent experiments.


Screening of soy protein-derived hypotriglyceridemic di-peptides in vitro and in vivo.

Inoue N, Nagao K, Sakata K, Yamano N, Gunawardena PE, Han SY, Matsui T, Nakamori T, Furuta H, Takamatsu K, Yanagita T - Lipids Health Dis (2011)

Effects of soy crude peptide (SCP)-LD3 on triglyceride (TG) synthesis in HepG2 cells (1 mg/mL) and hepatic TG level in Otsuka Long-Evans Tokushima fatty (OLETF) rats. Values are expressed as mean ± standard error of 5 samples in vitro and 6 rats in vivo. Asterisks indicate a significant difference at P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3116501&req=5

Figure 3: Effects of soy crude peptide (SCP)-LD3 on triglyceride (TG) synthesis in HepG2 cells (1 mg/mL) and hepatic TG level in Otsuka Long-Evans Tokushima fatty (OLETF) rats. Values are expressed as mean ± standard error of 5 samples in vitro and 6 rats in vivo. Asterisks indicate a significant difference at P < 0.05.
Mentions: In the first part of the current study, we evaluated the effects of SCP-LD3 treatment on TG synthesis in HepG2 cells. As shown in Figure 3A, incorporation of [1-14C] acetate into the cellular TG fraction was significantly lowered by SCP-LD3 treatment. These results suggest that SCP-LD3 has the ability to normalize lipid abnormalities possibly through the suppression of TG synthesis in hepatocytes. Next, we evaluated the effects of SCP-LD3 on lipid metabolism in OLETF rats. As shown in Figure 3B, 2-week feeding of SCP-LD3 alleviated the obesity-induced TG accumulation in the liver of OLETF rats without significant alterations in other growth parameters such as food intake (control, 29.2 ± 0.6 g/day; SCP-LD3, 29.0 ± 0.6 g/day) and final body weight (control, 539 ± 12 g; SCP-LD3, 531 ± 17 g). Additionally, serum TG level was also lowered by SCP-LD3 feeding in OLETF rats (control, 251 ± 40 mg/dL; SCP-LD3, 143 ± 21 mg/dL, P < 0.05). These results indicate that SCP-LD3 has TG-lowering properties, which led us to perform further isolation and identification of hypolipidemic peptide sequences from this peptide during subsequent experiments.

Bottom Line: In the third experiment, we found that Fraction-C (Frc-C) peptides, fractionated from hydrophilic peptides by gel permeation chromatography-high performance liquid chromatography, significantly reduced TG synthesis and apolipoprotein B (apoB) secretion in HepG2 cells.In the fourth experiment, we found that the fraction with 0.1% trifluoroacetic acid, isolated from Frc-C peptides by octadecylsilyl column chromatography, showed hypolipidemic effects in HepG2 cells.In the final experiment, we found that 3 di-peptides, Lys-Ala, Val-Lys, and Ser-Tyr, reduced TG synthesis, and Ser-Tyr additionally reduced apoB secretion in HepG2 cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Applied Biochemistry and Food Science, Saga University, Saga 840-8502, Japan.

ABSTRACT

Background: Soy protein and soy peptides have attracted considerable attention because of their potentially beneficial biological properties, including antihypertensive, anticarcinogenic, and hypolipidemic effects. Although soy protein isolate contains several bioactive peptides that have distinct physiological activities in lipid metabolism, it is not clear which peptide sequences are responsible for the triglyceride (TG)-lowering effects. In the present study, we investigated the effects of soy protein-derived peptides on lipid metabolism, especially TG metabolism, in HepG2 cells and obese Otsuka Long-Evans Tokushima fatty (OLETF) rats.

Results: In the first experiment, we found that soy crude peptide (SCP)-LD3, which was prepared by hydrolyze of soy protein isolate with endo-type protease, showed hypolipidemic effects in HepG2 cells and OLETF rats. In the second experiment, we found that hydrophilic fraction, separated from SCP-LD3 with hydrophobic synthetic absorbent, revealed lipid-lowering effects in HepG2 cells and OLETF rats. In the third experiment, we found that Fraction-C (Frc-C) peptides, fractionated from hydrophilic peptides by gel permeation chromatography-high performance liquid chromatography, significantly reduced TG synthesis and apolipoprotein B (apoB) secretion in HepG2 cells. In the fourth experiment, we found that the fraction with 0.1% trifluoroacetic acid, isolated from Frc-C peptides by octadecylsilyl column chromatography, showed hypolipidemic effects in HepG2 cells. In the final experiment, we found that 3 di-peptides, Lys-Ala, Val-Lys, and Ser-Tyr, reduced TG synthesis, and Ser-Tyr additionally reduced apoB secretion in HepG2 cells.

Conclusion: Novel active peptides with TG-lowering effects from soy protein have been isolated.

Show MeSH
Related in: MedlinePlus