Iridoid Glycosides as Key Discriminators of Cranberry ( <i>Vaccinium macrocarpon</i> ) Cultivars Revealed by UHPLC-HRAM-MSn Metabolomics

Abstract Background Cranberry (Vaccinium macrocarpon) contains diverse hydrophilic phytochemicals, but their compositional profiles and cultivar-specific variation have not been comprehensively characterized. Objective The objective of this study was to profile hydrophilic metabolites in cranberry cultivars and identify constituents that differentiate among cultivars. Methods Water-eluted fractions of Sephadex® LH-20–separated cranberry extracts from six cultivars (Crimson Queen, Demoranville, Haines, Mullica Queen, Stevens, and Welker) were analyzed using ultra-high-performance liquid chromatography–high-resolution accurate-mass tandem mass spectrometry (UHPLC-HRAM-MSn). Metabolites were annotated based on accurate mass and MS2 fragmentation data and comparison with literature reports. Sparse partial least squares–discriminant analysis (sPLS-DA) was applied to assess classification performance and identify discriminative features. Results Thirty-nine putative hydrophilic metabolites were identified, including hydroxycinnamic acid hexose derivatives, anthocyanins, hydroxycinnamoylquinic acids, and a distinct group of iridoid glycosides. Vaccinoside and several coumaroyl-substituted monotropein derivatives were structurally characterized in cranberry for the first time. sPLS-DA identified iridoid glycosides as key discriminators, with higher abundance observed in the Welker cultivar. Conclusions Cranberry cultivars contain previously unreported iridoid glycosides that contribute to chemotaxonomic differentiation. These results expand current knowledge of cranberry hydrophilic phytochemistry and support the relevance of iridoid glycosides as cultivar-informative metabolites.