Secondary metabolite mapping identifies peony episperm inhibitors of human hepatoma cells

As the main by-product during the oil production of peony seeds, the episperm is traditionally used as a lead component in folk herbal formulas for the cancer treatment in China. However, the investigation of its phytochemical foundation underlying anticancer effects remains an ongoing challenge. The work therefore determined growth inhibition activities of 8 solvent extracts of peony episperms in the human liver cancer cell line. This activity was then mapped onto the secondary metabolite profile of extracts by principal components analysis (PCA). The top 3 principal components of High Performance Liquid Chromatograph (HPLC)-PCA map discriminated extract activities mainly based on the differential content of 5 stilbene compounds, which were then tested individually. The trans-å-viniferin, gnetin-H, suffruticosol A, suffruticosol B, and suffruticosol C were thus determined as growth inhibitors and apoptosis inducers of human liver cancer cells with activities comparable to that of the antineoplastic cisplatin. A partial least squares regression-HPLC model was also constructed for the prediction of inhibitory effects of peony episperm extracts. These results expand the fundamental understanding of the peony episperms and support its current medicinal uses in China. Moreover, PCA-mediated secondary metabolite mapping was proved to be an efficient approach to qualify biomedical products required for pharmaceutical and medicinal uses.