Metabolomic profiling and quantitative comparison of inflorescences and succulent stems of Cynomorium songaricum Rupr. to evaluate their chemical resource potential

Abstract: Background: Cynomorium songaricum Rupr. is a national Class II protected, kidney-yang-tonifying medicinal herb. According to pharmacopoeia standards, only succulent stems are used medicinally, whereas inflorescences are discarded during processing, leading to massive resource waste. Previous studies have lacked systematic, multi-platform chemical comparisons of these two tissues, hindering rational reuse of inflorescence by-products. Objectives: This study aimed to characterize chemical differences between inflorescences and succulent stems through targeted quantification and broad-spectrum metabolomics to evaluate the potential of discarded inflorescence by-products as chemical resources for sustainable resource utilization. Methods: UV–visible spectrophotometry and high-performance liquid chromatography quantified total flavonoids, polysaccharides and three phenolic markers. Targeted ultra-performance liquid chromatography-tandem mass spectrometry metabolomics combined with principal component analysis and orthogonal partial least squares discriminant analysis was performed to screen differential metabolites. Results: Succulent stems contained higher total flavonoids (140.30 vs. 69.27 mg·g−1), gallic acid (4.5475 mg·g−1, undetected in inflorescences), p hydroxybenzoic acid (0.2935 vs. 0.1220 mg·g−1) and catechin (8.7567 vs. 1.4385 mg·g−1). Inflorescences contained more total polysaccharides (279.87 vs. 224.26 mg·g−1). In total, 469 differential metabolites were annotated. Specifically, 351 metabolites (mainly flavonoids and amino-acid derivatives) were enriched in succulent stems; 118 metabolites (lignans, coumarins and terpenoids) accumulated in inflorescences. Conclusion: Discarded inflorescences possess abundant tissue specific bioactive constituents, indicating potential for resource exploitation based on chemical profiles alone. This work provides chemical evidence supporting the reutilization of inflorescences, which may help mitigate overharvesting pressure on wild succulent stems and support circular conservation of this endangered medicinal plant. Such resource potential is inferred from metabolite profiling rather than from proven pharmacological efficacy. Further pharmacological validation of kidney yang tonifying activity and safety assessment are required before any medicinal application.