Chemical and biological comparison of different parts of Paeonia suffruticosa (Mudan) based on LCMS-IT-TOF and multi-evaluation in vitro

Paeonia suffruticosa Andr. (Mudan) as a famous medicinal and ornamental plant is widely cultivated in China. In the traditional Chinese medicine (TCM) system, only the root bark (Moutan Cortex) is used in the production of crude drugs. The present study aimed to systematically compare the chemical profiles and biological activities of different parts (root bark, root core, old stems, young stems, and leaves) of P. suffruticosa by LCMS-IT-TOF analysis and bioassay in vitro. In total, 55 constituents involving 15 monoterpene glycosides, 13 galloyl glucoses, seven gallic acid derivatives, four acetophenones, six flavonoids, and ten other compounds were characterized according to their UV absorptions, MS/MS fragmentation, and comparing with reference compounds. Interestingly, one new monoterpene, oxypaeoniflorgenin, was assigned by its MSn and UV patterns. Quantitative analysis demonstrated that gallic acid (2) mainly in leaves (5439.1 +/- 90.2 mu g/g), paeoniflorin (13) mainly in root bark (16,378.9 +/- 195.4 mu g/g), root core (17,130.2 +/- 125.9 mu g/g), and leaves (16,682.9 +/- 181.2 mu g/g), and benzoylpaeoniflorin (46) and paeonol (49) mainly in root bark (2360.1 +/- 41.4 and 10,142.3 +/- 252.5 mu g/g) and root core (2249.5 +/- 21.7 and 10,441.6 +/- 363.9 mu g/g) were the main constituents in P. suffruticosa. The chemical constituents of root bark and root core were similar and obviously different from the stems and leaves. All the five parts were assayed for their agonistic effect on four neurotransmitter receptors (MT1, MT2, 5-HT1A, and 5-HT2C) and antidiabetic potency on alpha-glucosidase, PTP1B, and DPPIV. Besides root bark, the root core, stems, and leaves were also revealed with fascinating activity in this study. The extraction rate of root bark (35.4% +/- 2.18) was two times higher than that of root core (18.4% +/- 0.81), supporting the traditional application. This investigation provides new perspectives for understanding the chemical divergence between different parts of P. suffruticosa and their comprehensive utilization.