Metabolomic Insights into Bee Bread Antiviral Activity Against Influenza A Virus

Bee bread (BB) is a natural apicultural product that exerts a broad spectrum of biological activities, including antimicrobial properties.The identification of novel antiviral agents is of considerable importance in light of the ongoing global impact of viral pathogens, particularly the influenza A virus (IAV).This study evaluated the antiviral efficacy of eighteen BB aqueous extracts against IAV H1N1 using Madin-Darby canine kidney (MDCK) cells.The cytotoxicity of the extracts varied significantly, ranging from 1.33 to 15.97 µL/mL.Real-time PCR analysis revealed a notable decline in a viral RNA copy number after the treatment with BB extracts, indicating inhibition of viral replication.The half maximal inhibitory concentration (IC₅₀) of extracts ranged from 0.13 to 1.09 µL/mL.Selectivity index (SI) showed significant variability, spanning from 2.13 to 47.68.Furthermore, BB samples revealed total phenolic content (TPC) ranging from 4.08 to 6.10 mg GAE/g, and total flavonoid content (TFC) between 0.22 and 0.97 mg QE/g.A significant negative correlation was observed between IC₅₀ and SI, whereas no significant associations were found between IC₅₀, or SI and TPC or TFC indicating that activity profiles of the extracts were independent of phenolic and flavonoid contents.Ultra-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS) profiling confirmed that bee bread contained a diverse set of bioactive metabolites, including flavonoids, phenolic acids, amino acids, lipids, and carbohydrate derivatives, supporting its potential as a multifunctional natural product.When combined with antiviral assays, these compositional insights suggest that the antiviral activity of bee bread likely results from the collective action of multiple compound classes rather than a single dominant group.