Abstract
Blueberry (Vaccinium corymbosum) leaves are often discarded as agricultural by-products despite their potential abundance in bioactive compounds. However, comprehensive knowledge of their phytochemical profile remains limited, especially at the cultivar level. To address this gap, this study performed untargeted metabolomic profiling of blueberry leaves from ten cultivars using UHPLC-QTOF MS. Metabolites were annotated using high-resolution mass spectrometry and MS/MS fragmentation patterns. Multivariate statistical techniques were employed to investigate inter-cultivar variability and identify distinctive metabolites. A total of 76 metabolites were discovered, with 64 being confidently annotated and grouped into ten main phytochemical classes. The relative abundances of phenolic acids, flavonols, and flavan-3-ols varied significantly among cultivars. Several metabolites were annotated for the first time in V. corymbosum leaves, such as miscanthoside, glucoliquiritin, apiin, khelloside, and aromadendrin. These metabolites are known in other plants for their biological activities, demonstrating blueberry leaves' bioactive potential. This study highlights the importance of untargeted metabolomic approaches in elucidating the biochemical diversity of plant matrices. The metabolomic data revealed significant cultivar-specific variations and novel bioactive metabolite annotation. These findings establish a complete phytochemical fingerprint for each cultivar, providing a basis for future research to validate key metabolites' biological activities and support the valorisation of V. corymbosum leaves.