Characterization of stilbenes, in vitro antioxidant and cellular anti-photoaging activities of seed coat extracts from 18 Paeonia species

Paeonia is famous as ornamental, medicinal plant, and edible oil crop in China. The seeds of peonies are rich in unsaturated fatty acids, monoterpene glycosides, sterols and stilbenes which have antioxidant and anti-inflammatory effects, etc. In this study, the composition and content of stilbenes in the seed coat extracts (SCE) from 50 populations of 18 species and two subspecies of Paeonia were determined by high performance liquid chromatography - diode array detection (HPLC-DAD). The results showed that the composition and content of stilbenes, especially suffruticosol B and gnetin H, differed significantly between Paeonia species, while there were small differences between populations of the same species. All the samples were clustered into two groups according to the stilbenes in SCE. The difference between the two groups was mainly reflected in the content of suffruticosol B and gnetin H. Furthermore, all samples showed high antioxidant activity, which was significantly positively correlated with the total polyphenol content. The SCE of P. anomala and P. lactiflora at different concentrations could effectively inhibit the production of matrix metalloproteinase 1 (MMP-1) in keratinocytes, and then achieve the effect of inhibiting cell aging. This study provided a valuable reference for the value-added utilization of Paeonia seed coat.