Hydrophilic β-conglycinin Peptide Reduces Hepatic Triglyceride Accumulation in Obese Model OLETF Rats

Abstract

We have previously demonstrated that soy β-conglycinin (βCG) peptide improves obesity and reduces lipid abnormalities in obese model Otsuka Long-Evans Tokushima fatty (OLETF) rats. In the present study, we fractionated βCG peptides by using hydrophobic synthetic absorbent materials and screened for peptide fractions with anti-obesity or hypolipidemic bioactivities. Wild-type Long-Evans Tokushima Otsuka (LETO group) and OLETF rats (control group) were provided a normal diet containing 20% casein. We prepared hydrophobic and hydrophilic peptides from βCG and fed OLETF rats diets in which 5% of the casein was replaced by either hydrophobic (the hydrophobic peptide group) or hydrophilic (the hydrophilic peptide group) peptides. After four weeks, hepatic triglyceride levels were lower in OLETF rats of the hydrophilic peptide group than in those of the control group due to decreased activity of hepatic fatty acid synthase, caused by the consumption of hydrophilic peptides. Although anti-obesity activity was not found in either βCG peptide fraction, the hydrophilic fraction of the βCG peptide could be a candidate for the identification of new peptide sequences that suppress hepatic lipid synthesis.