Chemical Profiling and Differential Constituents Analysis of Honghema and Its Easily Confusable Species Driven by High-Resolution Mass Spectrometry and Pattern Recognition

Background: Honghema is a traditional Chinese medicinal material and is also widely used by ethnic minority communities in Guizhou Province, where it is commonly known as “Reib ndad gunb” and “Uab Detdend”. The botanical origins were the whole plants of Laportea bulbifera (Siebold & Zucc.) Wedd. (L. bulbifera) and Girardinia diversifolia (Link) Friis (G. diversifolia). Due to morphological similarities, Urtica mairei H. Lév. (U. mairei) was often mixed as easily confusable species in actual market circulation. However, systematic research regarding the differences in chemical composition between the two botanical origins, as well as between them and their easily confusable species remain limited. This study aimed to comprehensively characterise the chemical constituents of L. bulbifera, G. diversifolia, and U. mairei, and to identify significantly differential chemical constituents for their discrimination. Methods: Data acquisition was performed using ultra-performance liquid chromatography–mass spectrometry (UPLC-MS). Multivariate statistical analyses combined with reference standard comparison were performed to investigate the differences in chemical profiles among L. bulbifera, G. diversifolia and U. mairei, identify the key differential constituents leading to the differences, and clarify their relative abundance information. Results: A total of 133, 77, and 59 chemical constituents were identified from L. bulbifera, G. diversifolia, and U. mairei, respectively. These compounds comprised flavonoids, organic acids, carbohydrates, organonitrogen compounds, terpenoids, coumarins, lipids, steroids, and other types of compounds. Flavonoids constituted the highest proportion of the compounds in L. bulbifera, whereas organic acids were the most abundant in G. diversifolia and U. mairei. Through multivariate statistical analysis, 32 inter-group differential components between L. bulbifera and G. diversifolia, 27 between L. bulbifera and U. mairei, and 13 between G. diversifolia and U. mairei were screened and identified. The core components contributing to these differences included Baimaside, Roxburic acid, 1-Galloyl-glucose, Protocatechuic acid 3-glucoside, and Schaftoside. Venn diagram analysis revealed 20 characteristic differential constituents of L. bulbifera, mainly represented by flavonoids; 6 characteristic differential constituents of G. diversifolia, primarily comprising terpenoids and organic acids; and 4 characteristic differential constituents of U. mairei, mainly represented by carbohydrates. Conclusion: Significant differences were observed among the chemical profiles of the three plant species. The method established in this study can effectively identify the chemical compositions of Honghema and its easily confusable species, revealing the key components responsible for the variations in their chemical profiles. This study provides a basis for elucidating the material foundation of Honghema and offers an effective analytical approach and valuable reference data for distinguishing Honghema from its easily confusable species.