Polyphenol-enriched fraction from a Chinese herbal compound granule protects against D-galactose-induced apoptosis and metabolic disorders in PC12 cells.

OBJECTIVES

To investigate the protective effects of polyphenol-enriched fraction (PEF) derived from a Chinese herbal compound granule (HCG) against D-galactose (DG) induced injury in PC12 cells, and to analyze the metabolic pathways related to PC12 cell proliferation and apoptosis through a hydrogen-nuclear magnetic resonance (H-NMR) metabonomic study.

METHODS

The PEF was separated from HCG extraction and quantified by ultraviolet spectrophotometry following purification. DG-induced PC12 cells were treated with three different dosages of PEF. Cell vitality was assessed by the MTT method, cell counts were obtained after β-galactosidase staining, and cell apoptosis was detected by flow cytometry. Then, H-NMR with partial least squares discrimination analysis (PLS-DA) and orthogonal partial least squares discrimination analysis (OPLS-DA) were performed to evaluate the intracellular metabolic profiles and pathways related to PC12 cell proliferation and apoptosis.

RESULTS

PEF significantly increased the PC12 cell survival rate, enhanced intracellular superoxide dismutase (SOD) activity, decreased malondialdehyde (MAD) levels, and inhibited both early and late apoptosis in response to DG-induced cytotoxicity. A total of 28 differential metabolites across 5 metabolic pathways, including phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine metabolism, glycine, serine and threonine metabolism, arginine biosynthesis, glyoxylate and dicarboxylate metabolism, were disturbed in PC12 cells.

CONCLUSION

The protective effect of PEF is likely mediated via regulating and improving the down-regulated metabolic pathways, leading to suppressed oxidative stress and inhibited apoptosis.