Comparative analysis of chemical components in different parts of Epimedium Herb

Epimedium herb is a well-known traditional Chinese medicine (TCM) that is used for treating kidney-yang deficiency, impotence and rheumatism, and flavonoids are the main active ingredients. The leaves and rhizomes of Epimedium herb are two separate kinds of medicinal materials with different functional indications and clinical applications. This study aimed to comprehensively analyze the chemical components of different parts of the herb from three Epimedium species (Epimedium sagittatum, E. pubescens and E. myrianthum) by using ultra high-performance liquid chromatography coupled with photo-diode array and quadrupole time-of-flight mass spectrometry (UHPLC-PDA-Q-TOF/MS) and multivariate statistical analysis to clarify the differences. Firstly, the workflow of UHPLC-Q-TOF/MS combined with UNIFI informatics was developed for characterizing the chemical compounds in different parts of Epimedium herb. Based on the exact mass information, the fragmentation characteristics and the retention times of compounds, all chromatographic peaks (74 chemical components) were identified. Secondly, 21 potential chemical markers for differentiating different parts of Epimedium herb were selected through PCA and PLS-DA analysis. The characteristic components in the leaves included flavonoids with Anhydroicaritin (type A, C-4' linked methoxy) as the backbone, and the characteristic components in the stems and rhizomes were Magnoline and flavonoids with Demethylanhydroicaritin (type B, C-4' linked hydroxyl) as the backbone. Thirdly, the UHPLC-PDA combined with heatmap visualization was employed to clarify the distribution of chemical components with high content in different parts of Epimedium herb. The results showed clear differences in the contents of chemical components in leaves, stems and rhizomes. The levels of flavonoids with Anhydroicaritin backbone were high in the leaves, and levels of flavonoids with Demethylanhydroicaritin backbone were high in the rhizomes. The levels of Magnoline in stems and rhizomes were higher than that in leaves. The contents of most of the compounds in stems remained low. The leaves and the other two parts (stems and rhizomes) can be distinguished by qualitative and semi-quantitative analysis of Magnoline and Epimedoside A (type B backbone). These results indicated that the different plant parts of Epimedium herb can be quickly and accurately distinguished by this method, establishing a foundation for the application of Epimedium herb.