Integrated GC–MS and UPLC-Q-Orbitrap MS untargeted metabolomics for the comprehensive identification of metabolites and characterization of metabolic pathways in key tissues of Cinnamomum cassia

Cinnamomum cassia , a commercially valuable aromatic medicinal plant, is widely used in the food, pharmaceutical and perfume industries. Here, we characterizd the metabolites and metabolic pathways in C. cassia bark, fruits and leaves using integrated GC–MS and UPLC-Q-Orbitrap MS techniques. A total of 71 volatile and 2882 non-volatile metabolites were identified, with terpenoids as the dominant class. Bark exhibited the highest volatile oil content (2.30%), which was dominated by trans -cinnamaldehyde (937 mg/g of oil). Tissue-specific biomarkers were screened from differential metabolites. Specifically, fruits accumulated higher levels of fatty acids, terpenoids and alkaloids relative to leaves, while bark was enriched in carbohydrates, phenylpropanoids, and terpenoids. Furthermore, a putative acetyl-CoA-centered inter-tissue metabolite exchange network was proposed, which might link photosynthate-derived acetyl-CoA from leaves to bark and fruits. This study advances our understanding of C. cassia metabolism and provides novel insights for its quality evaluation and comprehensive utilization of multi-tissue resources. • First tissue-specific C. cassia phytochemical profile via metabolic pathway analysis. • Bark showed the highest volatile oil content, with terpenoids predominant by GC–MS. • Fruits accumulated fatty acids specifically; bark was dominated by phenylpropanoids. • The proposed acetyl-CoA-centered network highlights potential metabolic crosstalk.