UHPLC-HRMS-Based Metabolomics To Evaluate the Antibacterial Compounds of Coix lacryma-jobi Seeds With Different Extraction Solvent Concentrations

Coix lacryma-Jobi L., commonly known as hanjeli, has traditional medicinal properties and potential antibacterial efficacy. The antibacterial potential of hanjeli seeds is attributed to their inherent metabolites. The composition and concentration of these metabolites in hanjeli seed extracts vary depending on the concentration of the extraction solvent used. Thus, selecting the optimal extraction solvent is crucial. This study employed a metabolomics approach using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS) to assess variations in metabolite profiles and antibacterial activities of hanjeli seeds under different extraction solvent concentrations (25%, 50%, and 75% ethanol). Extraction was conducted using the maceration method for 2 × 24 hours. In addition, metabolite profiles were analyzed using principal component analysis (PCA) and hierarchical clustering analysis (HCA) to distinguish the samples and correlate them with their antibacterial activity against Escherichia coli (E. coli). A total of 22 metabolites were putatively identified using UHPLC-HRMS. PCA effectively distinguished extracts based on extraction solvent concentration, whereas the HCA heatmap demonstrated variations in metabolite composition among the samples. The antibacterial activity of hanjeli seeds ranged from 33.16 ± 0.00% to 40.03 ± 2.14%. These findings indicate a significant influence of the extraction solvent concentration on the metabolite profile and antibacterial activity of hanjeli seeds.