1H Nuclear Magnetic Resonance Based Metabolomics Approach Reveals the Metabolic Mechanism of (-)-5-Hydroxy-equol against Hepatocellular Carcinoma Cells in Vitro.

1H nuclear magnetic resonance (NMR)-based metabolomics can rapidly detect metabolic shift under various stimulus; thus, it facilitated the dissection of the therapeutic mechanisms of compounds. (-)-5-Hydroxy-equol is an isoflavone metabolite that be obtained by microbial biotransformation. In the current work, the effect of (-)-5-hydroxy-equol on hepatocellular carcinoma (HCC) cells and its mechanism have been explored based on 1H NMR-based metabolomics approach. Our results revealed that (-)-5-hydroxy-equol can significantly inhibit the proliferation, migration, and invasion of SMMC-7721 cells and inhibit the proliferation of HepG2 cells. Metabolomics revealed that 17 differential metabolites involving in amino acid metabolism and energy metabolism were significantly changed inside and outside of the cells after treatment of (-)-5-hydroxy-equol. Specifically, (-)-5-hydroxy-equol at a concentration of 30 μM significantly decreased the concentrations of pyruvate, glutamate, and glucose. Because glycometabolism is a crucial feature of cancer-specific metabolism, we further verified enzymes and proteins that are closely relevant to glycometabolism. Our results indicated that (-)-5-hydroxy-equol-modulated glycolysis in HCC through the inhibition of activities of hexokinase, phosphofructokinase, and pyruvate kinase, and the expression of pyruvate kinase M2. This study revealed that metabolomic analysis integrating with further verifications at the biochemical level can facilitate understanding the anti-HCC mechanisms of (-)-5-hydroxy-equol.