Comparative metabolomic of cigar tobacco leaves: A preliminary investigation of potential discriminatory metabolites between Yunnan and Foreign

A systematic understanding of the metabolic components in cigar tobacco leaves (CTLs) from different ecological regions remains limited. This study aimed to clarify the substance differences between CTLs from Yunnan and major foreign production areas and to identify potential discriminant metabolites. A total of 25 CTL samples were collected from four production areas in Yunnan and five different foreign countries. The metabolic profiles were comprehensively characterized using continuous flow analysis, ion chromatography, GC-MS, and UPLC-MS/MS. The results revealed that Yunnan CTLs were characterized by a lower sugar-nicotine ratio and significantly higher contents of starch, pectin, and lignin compared to foreign samples. Phenolic acids, alkaloids, flavonoids, amino acids and derivatives, terpenoids, and lipids were identified as the primary components across all CTLs. A total of 398 differential metabolites (248 volatile and 150 non-volatile) were identified, predominantly from the classes of amino acids and derivatives, alkaloids, terpenoids, and lipids. From these, 12 metabolites were selected as potential candidates for distinguishing CTL origin. KEGG enrichment and MetOrigin analyses indicated that the differential metabolites were mainly involved in the biosynthesis of alkaloids, amino acids, flavonoids, lipids, and terpenes, with these pathways being significantly influenced by microorganism and enzyme-mediated carbon and nitrogen coupling metabolism. This exploratory study provides a metabolic foundation for improving production techniques and for the analysis of style-defining substances in Yunnan CTLs.