The complexes of soybean protein isolate and procyanidin B2 have synergistic hypolipidemic activity at the cellular level by activating the AMPKα pathway

The alkali method was used to prepare soybean protein isolate (SPI) and procyanidin B2 (PCB2) complexes, and the interaction between SPI and PCB2 was studied using multi-spectroscopic methods. The human hepatoma (HepG2) cell hyperlipidemia model was used to explore whether SPI-PCB2 has the potential for synergistic hypolipidemia. According to the findings, PCB2 was primarily linked to SPI via C-S and C-N bonds, and the addition of PCB2 reduced the α-helix structure content of SPI by 4.1%. At the cellular level, the optimal SPI-PCB2 ratio for lowering blood lipids was 1:1. Compared with the model group, the TG content and TC content in the 1:1 group were reduced by 28.7% and 26.3%, respectively. Western blot analysis revealed that SPI-PCB2 = 1:1 exerted synergistic hypolipidemic activity mainly by activating adenosine monophosphate-activated protein kinase α (AMPKα) phosphorylation, inhibiting 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR) and fatty acid synthetase (FAS) protein expression, and upregulating carnitine palmitoyl transferase 1A (CPT1A) protein activity.