In this study, a validated quality evaluation method with peony flower fingerprint chromatogram combined with simultaneous determination of sixteen bioactive constituents was established using UPLC-DAD-MS/MS. The results demonstrated that the method was stable, reliable, and accurate. The UPLC chemical fingerprints of 12 different varieties of peonies were established and comprehensively evaluated by similarity evaluation (SE), hierarchical cluster analysis (HCA), principal component analysis (PCA), and quantification analysis. The results of SE indicated that similar chemical components were present in these samples regardless of variety, but there were significant differences in the content of chemical components and material basis characteristics. The results of HCA and PCA showed that 12 varieties of samples were divided into two groups. Four flavonoids (11, 12, 13, and 16), five monoterpenes and their glycosides (3, 4, 6, 14, and 15), three tannins (7, 9, and 10), three phenolic acids (1, 2, and 5), and one aromatic acid (8) were identified from sixteen common peaks by standards and liquid chromatography–mass spectrometry (LC–MS). The simultaneous quantification of six types of components was conducted with the 12 samples, it was found that the sum contents of analytes varied obviously for peony flower samples from different varieties. The content of flavonoids, tannins, and monoterpenes (≥19.34 mg/g) was the highest, accounting for more than 78.45% of the total compounds. The results showed that the flavonoids, tannins, and monoterpenes were considered to be the key indexes in the classification and quality assessment of peony flower. The UPLC-DAD-MS/MS method coupled with multiple compounds determination and fingerprint analysis can be effectively applied as a feature distinguishing method to evaluate the compounds in peony flower raw material for product quality assurance in the food, pharmaceutical, and cosmetic industries. Moreover, this study provides ideas for future research and the improvement of products by these industries.

Mastitis is one of the most prevalent diseases in dairy cows, leading to significant economic losses and increased antibiotic usage. The development of safe and effective alternatives is therefore urgently needed. In this study, we investigated the protective effects of Forsythiaside A (FTA), a natural compound, against LPS-induced mastitis in bovine mammary epithelial (MAC-T) cells and a murine model. FTA significantly reduced intracellular reactive oxygen species (ROS), decreased lipid peroxidation, and restored antioxidant capacity. Furthermore, FTA increased the expression of GPX4 and SLC7A11, indicating inhibition of ferroptosis. The ferroptosis inducer RSL3 partially reversed these protective effects, supporting the involvement of GPX4-associated ferroptosis regulation in the protective effects of FTA. In vivo, FTA alleviated mammary tissue injury, reduced inflammatory cell infiltration, and improved redox balance. These findings suggest that FTA may serve as a potential natural therapeutic agent for mastitis, providing a promising alternative to antibiotic-based treatments in dairy production.