Quantitative Profiling of Phenolic Content of Carduus tenuiflorus Curt. Extracts Based on LC–HRMS

Phenolic compounds, as plant-derived secondary metabolites, are of significant interest in food and pharmaceutical research due to their antioxidant potential. While the Carduus genus is known for its phenolic richness, comprehensive quantitative data on Carduus tenuiflorus Curt. remains limited. In this study, the phytochemical profile of C. tenuiflorus extracts was investigated using liquid chromatography–high-resolution mass spectrometry (LC–HRMS). The analysis enabled the reliable identification and quantification of 25 phenolic compounds, primarily consisting of phenolic acids and flavonoids. Among the phenolic acids, chlorogenic acid was found to be the most abundant, followed by salicylic, quinic, and p-coumaric acids. Within the flavonoid fraction, diosmetin, luteolin, apigenin, and their corresponding glycoside and glucuronide derivatives were predominant. This phytochemical profile aligns with the phenylpropanoid-dominated composition previously reported for other Carduus species. These findings provide quantitative evidence that C. tenuiflorus possesses a rich profile of phenolic acids and flavonoids, contributing baseline data for future investigations into its bioactive properties. As biological activities were not experimentally assessed within this scope, further research incorporating functional and biological evaluations is required to fully understand the species' therapeutic potential.