Metabolomics analysis revealed the chemical mechanism of powerful antioxidant activity of Coffea arabica at high-altitude regions

Abstract : Coffea arabica is recognized as a functional beverage due to its nutritional and therapeutic potential, with efficacy attributed to abundant metabolites. However, how altitude affects its metabolite synthesis remains unclear. Herein, six groups of C. arabica across an altitudinal gradient were analyzed to explore altitude’s impacts on metabolite profiles and antioxidant capacity. UPLC-Q/TOF-MS identified 457 metabolites, including 40 differentially regulated metabolites (DRMs). Studies have found that the contents of soluble sugars and crude fiber in coffee decrease with increasing altitude, while the moisture content increases concurrently. DPPH• and ABTS•+ scavenging assays confirmed that the antioxidant activity of high-altitude coffee samples was significantly enhanced, and 14 metabolites (e.g., flavonoids and phenolic acids) exhibited a significant positive correlation with the antioxidant activity. The findings of this study provide a theoretical basis for the planning of high-quality coffee planting areas. • Untargeted metabolomics via UPLC-Q/TOF-MS identified 457 metabolites in Coffea arabica across six altitudinal gradients ranging from 1100 to 1600 m, with 40 altitude - responsive differential metabolites (DRMs); terpenoids, phenyl propanoids and polyketides, and organoheterocyclic compounds were core shared DRMs. • Altitude significantly reshapes the nutritional quality and metabolic profiles of Coffea arabica : soluble sugar and crude fiber contents show a strong negative correlation with altitude, while water content exhibits a strong positive correlation, flavonoids, phenolics, and glycerophospholipids are upregulated at high altitudes, contributing to enhanced antioxidant activity validated by DPPH and ABTS assays. • Correlation analysis and KEGG enrichment revealed that the primary metabolic pathways, plant hormone biosynthesis, and alkaloid biosynthesis are key regulatory pathways linking altitude, metabolite accumulation, and antioxidant capacity, with 14 metabolites (e.g., flavonoids, phenolic acids) showing a significant positive correlation with antioxidant activity.