Comprehensive chemical profiling and comparison of different medicinal cultivars of Paeonia lactiflora Pall

Paeonia lactiflora Pall. is an economically significant plant widely used in medicine and ornamentation, with a long history of cultivation. The prevalent cultivars of medicinal P. lactiflora in China display distinct morphological traits. Nevertheless, a systematic elucidation of their quality attributes remains to be achieved. This study employed ultra-performance liquid chromatography-quadrupole-orbitrap mass spectrometry (UPLC-Q-Orbitrap-MS) and ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS), combined with statistical analysis to investigate the metabolites of P. lactiflora roots in 17 medicinal cultivars from five major production regions in China. Significant morphological differences were observed in petal morphology, flower color, carpel features, as well as stem and leaf characteristics. In total, 167 compounds were identified or putatively characterized, including 101 phenolics, 36 terpenoids, 14 organic acids, eight amino acids, and eight other compounds (glycosides, polyols, lipids, and carbohydrates). The DD-SIMCA model established based on one-class classification successfully distinguished monopetalous red-flowered medicinal P. lactiflora from other types and differentiated herbs from Dao-di regions from those of non-Dao-di regions. Monopetalous red-flowered cultivars, representing an abundant germplasm resource, exhibited relatively high levels of terpenoids and phenolic compounds. This study has addressed the issue of compositional differences among different cultivars, screened out high-quality medicinal cultivars of P. lactiflora , and provided a theoretical basis for germplasm breeding work. Meanwhile, these findings offer a scientific rationale for the traditional view that MR cultivars are superior in traditional medicinal applications.