Widely Targeted Metabolomics Analysis Reveals Developmental Shifts in Antioxidants and Functional Peptides in Akebia trifoliata

Akebia trifoliata is an emerging fruit crop in China, valued for its medicinal and nutritional properties. To elucidate the developmental dynamics of its bioactive compounds, we performed widely targeted metabolomics using Ultra Performance Liquid Chromatography–Tandem Mass Spectrometry (UPLC-MS/MS) across four fruit developmental stages (S1–S4). A total of 1595 metabolites were identified, of which 988 were differentially accumulated and categorized into three distinct accumulation patterns. Flavonoids and phenolic acids exhibited a marked decline during fruit maturation, corresponding with decreasing antioxidant and α-glucosidase inhibitory activities. Conversely, functional oligopeptides and specific terpenoids accumulated significantly at later stages. K-means clustering revealed dynamic shifts in metabolic profiles, and 23 functional oligopeptides with antioxidative, antidiabetic, and ACE-inhibitory activities (angiotensin-converting enzyme, ACE) were predicted. KEGG enrichment highlighted stage-specific pathway transitions from flavonoid biosynthesis during early development to sugar metabolism at ripening. Correlation analysis identified key flavonoids, phenolic acids, and amino acid derivatives associated with antioxidant capacity and α-glucosidase inhibition. This study provides comprehensive metabolomic landscape of A. trifoliata fruit development and offers valuable insights for its functional exploitation in food and medicinal applications.