Integrative metabolomics and bioactivity profiling decipher the disparity between outer bark and parenchymatous tissue of Eriosema chinense Vogel root: Applications in enhancing shrimp shelf-life.

The root of Eriosema chinense Vogel (REC) is a traditionally used medicinal plant for treating diarrhea, orchitis, and hydrophobia. Outer bark (OB) and parenchymatous tissue (PT) are the root's crucial components, contributing to the variation in bioactive components and pharmacological effects. However, comprehensive and comparative information on the phytochemical components, bioactivities, and metabolite profiles of different parts of REC remains limited. In this study, we identified the metabolites present in OB and PT and elucidated the relationship between these metabolites and bioactivities. Our results revealed that OB contained significantly higher total phenol (114.21 mg GAE/g), flavonoid (242.17 mg RE/g), and antioxidant activities (ABTS and DPPH assays) than PT (p < 0.05). The OB extract also exhibited stronger antimicrobial effects against foodborne pathogens, including Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes, Escherichia coli, and Salmonella. The largest inhibition zone (24.29 mm) and the lowest MIC and MBC values (0.156 mg/mL and 1.25 mg/mL, respectively) were observed against Staphylococcus aureus. Metabolomic analysis identified 2297 metabolites, of which 633 were differentially accumulated. KEGG enrichment analysis identified five key metabolic pathways. Correlation analysis results showed that 40 potential metabolic biomarkers were strongly associated with bioactivities, with flavonoids constituting the majority. Application of REC extracts to shrimp storage demonstrated that the OB extract most effectively inhibited microbial growth, reducing total viable counts and psychrophilic bacterial counts after 13 days. Additionally, it mitigated lipid oxidation (thiobarbituric acid reactive substances <3 mg/kg) and delayed increases in pH and total volatile basic nitrogen, thereby extending the shrimp shelf-life.