The Effects of C3G and D3G Anthocyanin-Rich Black Soybean on Energy Metabolism in Beige-like Adipocytes

Various mechanisms of obesity prevention have been identified; however, the roles of brown or beige fat as regulators of the energy balance are unclear. The effects of anthocyanin-rich black soybean, Glycine max (L.) Merr., testa (ABS) extracts on the energy balance were investigated by comparing beige-like adipocytes (BLA) and white adipocytes (WAT). ABS extracts reduced peroxisome proliferator-activated receptor gamma protein expression and triglyceride accumulation in WAT and BLA without inducing nuclear damage. The biomarkers of fat degradation (phospho-AMPKα and ATGL) or glycerol secretion in the medium and β-oxidation of fatty acids (CPT2) in the ABS-treated BLA were increased compared to those in WAT. ABS extracts significantly increased the expression of thermogenesis markers (UCP1 and CIDEA) and biomarkers related to mitochondrial activation (cytochrome c and NRF1) in BLA. In the primary cell culture of brown adipocytes (BAT) from rats fed ABS, the expression levels of PGC1-α, cytochrome c, and UCP1 proteins were increased compared to those in BAT from nonfed rats. A reduction in the NAD/NADH ratio was consistently associated with an increase in the oxygen consumption rate and basal/maximal respiration rate in ABS-treated BLA. Anthocyanins promote beiging in the body, contribute to the prevention of obesity, and are potentially useful functional materials.