IntroductionSeasonal variation can influence plant metabolite composition and modify antimicrobial performance; however, the relationship between seasonal metabolomic changes and antibacterial activity remains poorly understood in many arid-land medicinal plants. To our knowledge, this is the first study to integrate GC–MS metabolomics, antibacterial screening, and phage–extract interaction testing in Abutilon pannosum.MethodsLeaf extracts of Abutilon pannosum collected during late summer (S1, September 2024), autumn (S2, November 2024), and winter (S3, February 2025) were analyzed using GC–MS. Antibacterial activity was evaluated against selected bacterial isolates using diffusion-based assays and MIC/MBC determination. The interaction between seasonal extracts and phage CF01 was further assessed against Escherichia coli O157:H7 under sub-MIC extract concentrations.ResultsGC–MS analysis resolved the curated dataset into 350 putatively annotated parent metabolites, and PCA demonstrated clear season-dependent metabolomic separation, with 16 metabolites differing significantly among collection periods. S2 exhibited the broadest diversity of literature-supported antibacterial candidates, including α-linolenic acid, citronellol, dodecanoic acid, farnesol, ferulic acid, and 4-hydroxybenzoic acid, whereas S3 was enriched in caffeic acid, p-coumaric acid, D-limonene, and xylitol. Antibacterial activity varied according to season and bacterial isolate, with Staphylococcus aureus showing the highest susceptibility, while Escherichia coli exhibited weaker direct sensitivity. Phage–extract interaction assays demonstrated that CF01 enhanced Escherichia coli O157:H7 suppression at sub-MIC extract concentrations, particularly when extract-only treatment resulted in incomplete bacterial inhibition, with stronger enhancement patterns observed for S2 and S3 extracts.DiscussionIntegrated metabolomics–bioactivity analysis identified citronellol and α-linolenic acid as candidate metabolites potentially associated with extract-mediated Escherichia coli reduction, while p-coumaric acid, citronellol, and α-linolenic acid showed positive associations with phage-enhanced antibacterial activity. These findings demonstrate that the antibacterial potential of Abutilon pannosum is season-dependent and support combining seasonal metabolomics, plant extract screening, and phage–extract strategies as an approach for identifying bioactive desert-plant metabolites against Escherichia coli O157:H7.