Metabolomics reveals stage-dependent metabolic dynamics associated with quality variation during the development of Albizia julibrissin flower

Albizia julibrissin flowers (AJF), known as “He Huan Hua,” are widely used as scented tea and herbal medicine in China. During flower maturation, significant changes in metabolite composition occur. To explore the quality alterations of AJF at different development stages, phytochemical assays combined with bioactivity evaluation were conducted. Tight buds exhibited stronger antioxidant and anti-neuroinflammatory activities than fully opened flowers, despite containing lower levels of conventional quality indicators (quercitrin, total flavonoids, and total phenolics). To characterize metabolic dynamics during AJF development, untargeted metabolomics was used and identified 227 differential metabolites, of which 49 showed consistent changes across all three stages. Distinct stage-specific metabolic patterns were observed, with carotenoids and procyanidins enriched in tight buds, anthocyanins and fatty acyls in mature buds, and triterpenoids in fully opened flowers. Moreover, several differential metabolites enriched in tight buds, including lutein, avicularin, procyanidin B2, and ginsenoside Rh 2 , showed associations with anti-neuroinflammatory activity based on in vitro evaluation. In conclusion, stage-dependent metabolic reprogramming contributes to significant quality variation in the development of AJF. These findings provide a foundation for optimizing harvest timing and supporting graded utilization of AJF based on metabolic signatures.