Metabolomic analysis reveals flavonoid accumulation patterns in four apricot cultivars

Flavonoids are important secondary metabolites that contribute to the nutritional quality and sensory characteristics of apricot fruit; however, their variation across cultivars and fruit tissues remains insufficiently characterized. Following an initial survey of total flavonoid content across 123 apricot accessions, four cultivars with contrasting levels were selected for UPLC-MS/MS profiling of the peel and flesh. In total, 760 flavonoid metabolites were identified and quantified, most of which accumulated at higher levels in the peel, indicating that the peel is a major flavonoid-rich tissue in these cultivars. Multivariate analysis identified 35 and 34 key differentially accumulated metabolites in the flesh and peel, respectively. Cultivar-specific differences involved distinct flavonoid classes: 'Luotuohuang' (LTH) was enriched in proanthocyanidin A2*, whereas 'Zixing' (ZX) preferentially accumulated rhamnosylated and acetylated flavonoid glycosides. These findings characterize tissue- and cultivar-specific flavonoid variation and highlight valuable flavonoid resources for apricot breeding and peel by-product utilization.