Beyond saponins: An integrated mass spectrometry strategy for profiling, spatial mapping, and rapid authentication of non-saponin constituents in Panax species.

Non-saponin constituents of Panax species, including amino acids, sugars, and nucleosides, have attracted increasing attention due to their nutritional relevance and potential health benefits in food-medicine homologous materials. However, their high polarity and chemical diversity pose significant challenges for comprehensive characterization, limiting their application in food quality evaluation and authenticity assessment. In this study, an integrated mass spectrometry-based workflow was developed to systematically profile water-soluble non-saponins in Panax ginseng, Panax notoginseng, and Panax quinquefolius, which are widely consumed as functional foods, dietary supplements, and traditional herbal products. An offline two-dimensional LC-MS platform was first established to improve the separation and enrichment of polar constituents, followed by feature-based molecular networking (FBMN) and machine learning-assisted structural annotation using the SIRIUS platform. A total of 201 non-saponin compounds were characterized, revealing remarkable interspecies differences in non-saponin composition. Subsequent non-targeted metabolomics identified quinic acid, raffinose, and trehalose as key species-specific markers with nutritional and quality-discriminating relevance. Furthermore, desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was employed to visualize the spatial distribution of representative non-saponins, uncovering tissue-specific accumulation patterns associated with species identity. Finally, a portable nano-electrospray ionization miniature mass spectrometry (nESI-Mini MS) approach was developed for rapid species authentication, enabling high-throughput, on-site analysis with minimal sample preparation. Overall, this study provides an integrated analytical strategy for elucidating the chemical diversity, spatial distribution, and food-related quality attributes of non-saponin constituents in Panax species, offering practical tools for functional food evaluation, authenticity verification, and quality control.