The "depict" strategy for discovering new compounds in complex matrices: Lycibarbarspermidines as a case

The comprehensive detection and identification of active ingredients in complex matrices is a crucial challenge. Liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) is the most prominent analytical platform for the exploration of novel active compounds from complex matrices. However, the LC-HRMS-based analysis workflow suffers from several bottleneck issues, such as trace content of target compounds, limited acquisition for fragment information, and uncertainty in interpreting relevant MS2 spectra. Lycibarbarspermidines are vital antioxidant active ingredients in Lycii Fructus, while the reported structures are merely focused on dicaffeoylspermidines due to their low content. To comprehensively detect the new structures of lycibarbarspermidine derivatives, a "depict" strategy was developed in this study. First, potential new lycibarbarspermidine derivatives were designed according to the biosynthetic pathway, and a comprehensive database was established, which enlarged the coverage of lycibarbarspermidine derivatives. Second, the polarity-oriented sample preparation of potential new compounds increased the concentration of the target compounds. Third, the construction of the molecular network based on the fragmentation pathway of lycibarbarspermidine derivatives broadened the comprehensiveness of identification. Finally, the weak response signals were captured by data-dependent scanning (DDA) followed by parallel reaction monitoring (PRM), and the efficiency of acquiring MS2 fragment ions of target compounds was significantly improved. Based on the integrated strategy above, 210 lycibarbarspermidine derivatives were detected and identified from Lycii Fructus, and in particular, 170 potential new compounds were structurally characterized. The integrated strategy improved the sensitivity of detection and the coverage of low-response components, and it is expected to be a promising pipeline for discovering new compounds.

Mass spectrometric detection combined with bioinformatic analysis identified possible protein markers and key pathways associated with bladder cancer

We aimed to find possible protein markers and key pathways related to bladder cancer. In total, we extracted three bladder cancer tissues and three paracancerous tissues from Jiangsu Provincial People's Hospital Urology Department, and performed mass spectrometric detection with Q Exactive. Subsequently, we screened the differentially expressed proteins in the disease group and the normal group using the LIMMA package, and performed functional enrichment analyses using DAVID. Further, we constructed protein-protein interaction (PPI) networks with Cytoscape software, and analyzed modules with ClusterONE. In total, 165 differentially expressed proteins including 19 upregulated and 146 downregulated ones were obtained. ACTA2 (Actin, Alpha 2, Smooth Muscle, Aorta), ACTN1 (Actinin, Alpha 1), and VCL (Vinculin) were significant nodes with higher degrees in the PPI network. These three nodes were also hub nodes in module 2. Besides, functional enrichment analysis suggested that ECM-receptor interaction and focal adhesion were significant pathways, and these two pathways were also enriched in three network modules. In addition, ACTN1 and VCL were enriched in the focal adhesion pathway in module 2. Thus, ACTA2, ACTN1, and VCL may play important roles in bladder cancer progression and may be protein markers for this disease. The ECM-receptor interaction pathway and the focal adhesion pathway may be involved in the progression of bladder cancer. Furthermore, ACTN1 and VCL may play roles in bladder cancer development, partly via the focal adhesion pathway.

Nonaqueous Capillary Electrophoresis Mass Spectrometry

The term nonaqueous capillary electrophoresis (NACE) commonly refers to capillary electrophoresis with purely nonaqueous background electrolytes (BGE). Main advantages of NACE are the possibility to analyze substances with very low solubility in aqueous media as well as separation selectivity that can be quite different in organic solvents (compared to water)-a property that can be employed for manipulation of separation selectivities. Mass spectrometry (MS) has become more and more popular as a detector in CE a fact that applies also for NACE. In the present chapter, the development of NACE-MS since 2004 is reviewed. Relevant parameters like composition of BGE and its influence on separation and detection in NACE as well as sheath liquid for NACE-MS are discussed. Finally, an overview of the papers published in the field of NACE-MS between 2004 and 2014 is given. Applications are grouped according to the field (analysis of natural products, biomedical analysis, food analysis, analysis of industrial products, and fundamental investigations).