Comprehensive Phytochemical Profiling and Antiphage Activity of Methanolic Extract of Withania somnifera against Lactic Acid Bacteriophages

Introduction: Bacteriophages present a significant challenge to commercial dairy manufacturing facilities impacting product quality and causing great economic losses to the dairy industry. Despite routine phage control measures, these phages exhibit resistance to conventional methods, including pasteurization. Withania somnifera (L.) Dunal is a popular medicinal plant traditionally used in Ayurvedic medicine and has various health benefits. Objectives: This study is aimed at conducting a comprehensive phytochemical analysis and evaluating its potential in preventing Lactococcus phage infections in the dairy industry. Materials and Methods: In this study, qualitative and quantitative phytochemical testing, HPTLC fingerprinting, LC-MS and GC-MS of Withania somnifera methanolic root extract were done. The MIC of the methanolic extract against the probiotic host was determined and antiphage activity of the methanolic extract was done against Lactococcus lactis P001 phage at a concentration that did not inhibit the probiotic host. Results: Qualitative tests revealed the presence of secondary metabolites like alkaloids, phenolic compounds, and tannins in the plant extract, while LCMS and GCMS identified various bioactive compounds. Antiphage assay using crude methanolic extracts demonstrated a significant reduction in the phage titre with a log reduction 0.713±0.08 after 20 min of exposure and 0.736±0.18 after 90 min of exposure without any observed inhibition of the host. Conclusion: These findings offer valuable insights into the extract’s potential in preventing phage infection within lactic probiotic cultures.