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Although both rhizome and root of Panax notoginseng are officially utilized as notoginseng in “Chinese Pharmacopoeia”, individual parts of the root were differently used in practice. To provide chemical evidence for the differentiated usage, quantitative comparison and metabolite profiling of different portions derived from the whole root, as well as commercial samples, were carried out, showing an overall higher content of saponins in rhizome, followed by main root, branch root, and fibrous root. Ginsenoside Rb2 was proposed as a potential marker with a content of 0.5 mg/g as a threshold value for differentiating rhizome from other parts. Multivariate analysis of the metabolite profile further suggested 32 saponins as potential markers for the discrimination of different parts of notoginseng. Collectively, the study provided comprehensive chemical evidence for the distinct usage of different parts of notoginseng and, hence, is of great importance for the rational application and exploitation of individual parts of notoginseng.

The emerging field of sphingolipidomics calls for accurate quantitative analyses of sphingolipidome. Existing analytical methods for sphingolipid (SPL) profiling often suffer from isotopic/isomeric interference, leading to the low-abundance, but biologically important SPLs being undetected. In the current study, we have developed an improved sphingolipidomic approach for reliable and sensitive quantification of up to 10 subclasses of cellular SPLs. By integratively utilizing high efficiency chromatographic separation, quadrupole time-of-flight (Q-TOF) and triple quadrupole (QQQ) mass spectrometry (MS), our approach facilitated unambiguous identification of several groups of potentially important but low-abundance SPLs that are usually masked by isotopic/isomeric species and hence largely overlooked in many published methods. The methodology, which featured a modified sample preparation and optimized MS parameters, permitted the measurement of 86 individual SPLs in PC12 cells in a single run, demonstrating great potential for high throughput analysis. The improved characterization, along with increased sensitivity for low-abundance SPL species, resulted in the highest number of SPLs being quantified in a single run in PC12 cells. The improved method was fully validated and applied to a lipidomic study of PC12 cell samples with or without amyloid β peptide (Aβ) treatment, which presents a most precise and genuine sphingolipidomic profile of the PC12 cell line. The adoption of the metabolomics protocol, as described in this study, could avoid misidentification and bias in the measurement of the analytically challenging low-abundance endogenous SPLs, hence achieving informative and reliable sphingolipidomics data relevant to discovery of potential SPL biomarkers for Aβ-induced neurotoxicity and neurodegenerative disease.