β-Conglycinin Embeds Active Peptides That Inhibit Lipid Accumulation in 3T3-L1 Adipocytes in Vitro

Abstract

Obesity is a worldwide health concern because it is a well-recognized predictor of premature mortality. The objective was to identify soybean varieties that have improved potential to inhibit fat accumulation in adipocytes by testing the effects of soy hydrolysates having a range of protein subunit compositions on lipid accumulation and adiponectin expression in 3T3-L1 adipocytes. The results showed that differences in the protein distribution of 15 soy genotypes led to different potentials for the reduction of fat accumulation. The inhibition of lipid accumulation of soy alcalase hydrolysates in 3T3-L1 adipocytes ranged from 29 to 46%. Soy hydrolysates made from genotypes with 45.3 ± 3.3% of total protein as β-conglycinin, on average, showed significantly higher inhibition of lipid accumulation compared to those with 24.7 ± 1.5% of extracted total protein as β-conglycinin. Moreover, after in vitro simulated digestion with pepsin−pancreatin of the soy alcalase hydrolysates, 86% of the original activity remained. Adiponectin expression was induced in 3T3-L1 adipocytes treated with 15 soy hydrolysates up to 2.49- and 2.63-fold for high and low molecular weight adiponectin, respectively. The inhibition of lipid accumulation calculated from a partial least squares (PLS) analysis model correlated well with experimental data (R 2 = 0.91). In conclusion, it was feasible to differentiate soy varieties on the basis of the potential of their proteins to reduce fat accumulation using a statistical model and a cell-based assay in vitro. Furthermore, β-conglycinin embeds more peptides than glycinin subunits that inhibit lipid accumulation and induce adiponectin in 3T3-L1 adipocytes. Therefore, soy ingredients containing β-conglycinin may be important food components for the control of lipid accumulation in adipose tissue.

Antioxidant Capacity of Alcalase Hydrolysates and Protein Profiles of Two Conventional and Seven Low Glycinin Soybean Cultivars

“…1a shows the gel with six major protein bands corresponding to BC subunits (α, α' and β) ranging from 45 to 67 kDa and GL subunits (A1, 2, 3, 4, and basic chains) ranging from 20.5 to 38.5 kDa. The identities of these protein bands agreed with previously reported studies [9,24,32]. Cultivars 1F and 6F showed intense bands on A1,2,4 chain (35 kDa) and basic chain (20.5 kDa) of GL whereas the other cultivars had more intense bands on α chain (60 kDa) and α' chain (65 kDa) of BC.…”

“…Soy peptides produced from alcalase hydrolysis play a role in regulating body weight [8] and controlling lipid accumulation [9]. The postprandial antioxidant protection imparted by a significant increase in human serum antioxidant capacity was not detectable following acute consumption of 25 g soy protein [10].…”

Soy, phytoestrogens and their impact on reproductive health

“…Some of the health benefits attributed to soy may result from the release of biologically active peptides by enzymatic proteolysis during gastrointestinal digestion or during the fermentation of soy proteins. For example, bioactive peptides encrypted in the amino acid sequence of soy proteins, in particular b-conglycinin, have been found to exert anticancer, antihypertensive, hypocholestorolemic, antiobesity and antioxidant activities (Martinez-Villaluenga et al, 2008, 2009Martinez-Villaluenga et al, 2010;Wang et al, 2008). Soybean also contains a wide range of micronutrients and phytochemicals including phytic acid (1.0-2.2%), sterols (0.23-0.46%), and saponins (0.17-6.16%), the effects of which have recently been reviewed in detail by Kang et al (2010).…”

Protein hydrolysates from β‐conglycinin enriched soybean genotypes inhibit lipid accumulation and inflammation in vitro

“…The hydrolysates were prepared as described by MartinezVillaluenga et al [17]. Briefly, 2 g of defatted soy flour were added to 25 mL of deionized water and brought to 508C at pH 8.0.…”