# Legumes as Functional Food for Cardiovascular Disease
## 3 Legumes as Functional Food for Cardiovascular Diseases
### Cardiovascular Benefits of Soybean 7S \(\beta\)-Conglycinin  
The soybean 7S \(\beta\)-congplycinin are ascribed in various preventive roles against oxidative stress, hypertension, hypercholesterolemia, dyslipidemia and obesity and cancer [64; 116; 133; 134; 135; 136; 137; 138; 139; 140; 128]. In vitro studies showed that the soy 7S protein stimulated the expression of the genes involved in fatty acid \(\beta\)-oxidation and LDL-receptors and the degradation of LDL, reduced cholesterol ester synthesis and suppressed apolipoprotein B-100 (APO B-100) secretion in cultured HepG2 hepatocytes [142; 143; 144]. These results were later confirmed where such cholesterol reduction was attributed to the stimulation of the LDL receptors and the degradation of LDL in cultured HepG2 hepatocytes [142; 146]. This soybean \(\beta\)-congplycinin was also shown to control dyslipidemia in both animal models and humans comparable to the commonly used drugs such as statins [133; 134; 135; 136; 137]. [PERSON] et al., (1992) [142] showed the first in vivo evidence involving this soybean 7S globulin to reduce TAG and TC levels in rats by 35% that is comparable to clofibrate. In human clinical trials, this \(\beta\)-congplycinin consumption led to decreased levels in serum TAGs, fat, lipid accumulation and body:fat ratio [148; 100; 149]. [PERSON] et al., (2009) [144] also found that soy 7S \(\beta\)-congplycinin peptides also stimulated the nuclear transcription factor SREBP-2 which led to reduced levels of cholesterol. These SREBP transcription factors induce genes associated with cholesterol biosynthesis, the LDL receptor, and the regulators of the entry of cholesterol [144]. SREBP-2 is further controlled by the mTOR1 pathway through autophagy as the SREBP-2 transcription factor can bind to the promoter of several autophagy-related genes including _LC3_, _Atg4B_ and _Atg4d_. Cells with SREBP-2 knockout led to the decreased formation of autophagosomes and the induction of the co-localization of lipid droplets with the autophagy LC3 marker [159]. Enzymatic digestion of soybean protein produced small (3-20 kDa) peptides and comparing to a small synthetic LRVPAGTTFYVVNDNDENLRMIA peptide (MW = 2.3 kDa), corresponding to 127-150 th position of the soybean 7S globulin, exhibited the same effect to modulate LDL receptor activity as that of the complete 7S globulin in cultured hepatic HepG2 cells [116]. Consumption of this 7S globulin decreased serum TAGs in both normal and genetic obese mice [147; 108] and in humans [136; 137]. [PERSON] et al., (2010) [134] showed that supplementation of this major \(\beta\)-congplycinin soybean storage globulin (200 mg/day) to Wistar rats fed with a high-cholesterol diet for 28 days lowered plasma TC and TAG levels and LDL:HDL ratios and upregulated the \(\beta\)-VLDL receptor. The 7S \(\beta\)-congplycinin is made up of three subunits (alpha, alpha' and beta) that share a large degree of amino acid homology [103; 108; 129]. Of these three subunits, it is the alpha' subunit that is directly involved in the hypocholesterolemomic effect of soybean as evidenced by the upregulation of the LDL receptors in human HepG2 cultured cells [116; 145; 146; 150]. [PERSON] et al., (2004) [135] showed that it is this alpha'-subunit of the soybean 7S globulin that was associated with the lowered plasma lipid and upregulation of \(\beta\)-VLDL receptors in rats fed with a high-cholesterol diet. In rat studies, this 7S globulin alpha' subunit decreased plasma TC and TAGs. In this study, increasing concentrations of either the 7S globulin (100 or 200 mg/kg/day) or the 7S globulin alpha'-subunit (10 or 20 mg/kg/day) was observed to significantly decrease plasma TC and TAG levels. Using either the 7S globulin (100 or 200 mg/kg/day) or 7S globulin alpha'-subunit (20 mg/kg/day) exhibited statistically similar contributions (\(p<0.001\)) in lowering plasma TC and TAG levels compared to clofibrate (200 mg/kg/day) [135].