Chemical Diversity and Distribution of Specialized Metabolites Across Different Organs of <i>Gentiana rigescens</i> Franch.

This study comprehensively investigated the distribution and diversity of specialized metabolites in different parts of Gentiana rigescens Franch. (G. rigescens). Ultra-performance liquid chromatography (UPLC) was utilized to quantify the major active constituents, while UPLC-electrospray ionization-quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) enabled rapid putative identification and structural characterization of specialized metabolites. The results revealed that the gentiopicroside content in all plant parts met the minimum requirement of 1.5% stipulated in the Pharmacopoeia of the People's Republic of China (2020 edition). Notably, the concentrations of loganic acid, sweroside, mangiferin, and amarogentin were significantly higher (p < 0.01) in the flowers, whereas swertiamarin and gentiopicroside were more abundant in the roots and rhizomes. The UPLC chromatographic profiles of the different parts exhibited high similarity, sharing 29 characteristic peaks. In total, 26 compounds were putatively identified across the plant, comprising 13 iridoids, 7 flavonoids, 3 triterpenoids, and 3 xanthones, including four compounds reported for the first time within the G. rigescens. Principal component analysis (PCA) further indicated that the chemical profiles of the leaves and flowers were closely related, yet distinct from those of the roots, rhizomes, and stems. Collectively, these findings elucidate the compositional variation and distribution patterns of specialized metabolites among different plant parts, providing a scientific foundation for the comprehensive utilization of G. rigescens in ethnic and traditional medicinal practices in Yunnan, China.