Assessment of the differentiation of Sambucus nigra plant parts using a multi-target and suspect screening by LC-HRMS and ICP-OES

Traditional plant medicine is among the most popular and strongest growing forms of alternative medicine. Based on ancient healing practices, it still plays a significant role in the treatment of many medical conditions. Its impact significantly influenced the creation of therapeutic products by using medical herbs in a continuously growing market. Therefore, it is important to properly characterize and differentiate medical plant parts. In this work, a multi-target and suspect screening approach for the elemental composition as well as the organic compound profile of different plant parts of Sambucus nigra was assessed using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) to identify potential biomarkers and establish their correlations with the total phenolic content (TPC). For the elemental analysis, calcium and potassium were found as the main elements screened in the S. nigra plant parts, but with no correlation to the TPC content. In contrast, phosphorus showed a slight correlation with the TPC and significant correlations with concentrations of several phenolic compounds. Regarding the organic compound profile, 88 features were tentatively identified with high confidence (levels 1-3), some of them for the first time in S. nigra. These compounds are mainly associated with phenolic compounds such as flavonoids or cinnamic acid derivatives, among others. Moreover, 18 of these compounds were identified as potential biomarkers to differentiate between plant parts (i.e. rutin, quercetin, bergapten, etc.). These findings not only give insights into the characterization of S. nigra but might serve as a basis for evaluating individual substances as well as different plant parts regarding their potential hepatoprotective characteristics. The LC-HRMS method could serve as a basis for future analyses of medicinal plants, aiming for reduced analysis time, high separation performance (especially for phenolic compounds), and better result comparability.