A comprehensive analytical framework integrating liquid chromatography-tandem mass spectrometry metabolomics with chemometrics for metabolite profiling of lettuce varieties and discovery of antibacterial agents

This study comprehensively characterized the metabolite profiles of six lettuce varieties and established the correlation between the elucidated profiles and their antivirulence effects. A total of 195 metabolites were annotated using LC-QTOF-MS/MS metabolomics assisted by molecular networking and integrated with chemometrics. Red varieties (red longifolia and lolla rosa) demonstrated higher chlorogenic and chicoric acids suggesting their antioxidant properties. In parallel, amino acids and disaccharides were enriched in romaine longifolia rationalizing its palatable taste and nutritional potential, while crispa, capitata, and lolla bionda presented a high & beta;-carboline alkaloid content. The antibacterial and antihemolytic potential of all varieties against methicillin-sensitive and methicillin-resistant Staphylococcus aureus was assessed and validated by prominent downregulation of & alpha;-hemolysin transcriptional levels in both strains. Moreover, correlation analysis revealed sesquiterpenes, & beta;-carboline alkaloids, amino acids, and oxy-fatty acids as the main bioactives. Results emphasize lettuce significance as a functional food and nutraceutical source, and highlight varieties naturally rich in antibacterial agents to adapt breeding programs.

Automated summary

This study characterized the metabolite profiles of six lettuce varieties and established their correlation with antivirulence effects. Various metabolites were identified, and red varieties showed higher levels of chlorogenic and chicoric acids indicating antioxidant properties. Romaine longifolia exhibited enrichment in amino acids and disaccharides, while crispa, capitata, and lolla bionda had a high content of β-carboline alkaloids. All varieties demonstrated antibacterial potential against Staphylococcus aureus strains, and specific bioactives such as sesquiterpenes, β-carboline alkaloids, amino acids, and oxy-fatty acids were identified. The results highlight the significance of lettuce as a functional food source and suggest breeding programs should focus on varieties rich in antibacterial agents.