Unlocking the antibacterial power of Morus alba L. against methicillin-resistant Staphylococcus aureus

Background: Antimicrobial resistance remains a critical global health concern, necessitating the exploration of alternative treatments. This research aimed to evaluate the antimicrobial efficacy of Morus alba stem against methicillin-resistant Staphylococcus aureus (MRSA).Methods: The leaves and stems of M. alba were extracted using decoction and maceration methods with water and ethanol as solvents and assess their antimicrobial activity. Results: An ethanol extract of Morus alba stem exhibited potent antibacterial activity against all tested bacteria, with MIC ranging from 0.3125 to 20 mg/mL and MBC from 0.625 to 40 mg/mL. At four times the MIC concentration, the extract eliminated Staphylococcus aureus within 4 hours. Proteomic analysis revealed significant alterations in protein expression post-exposure, including upregulation of GlmU, N-acetylneuraminate lyase, and ribonuclease E, and downregulation of ribose-phosphate pyrophosphokinase and SecA. Pathway analysis indicated upregulation of N-acetylneuraminate catabolic process, secondary metabolite biosynthesis, and RNA polymerase activity, while protein export, redox-active center activity, and fatty acid synthase activity were downregulated. Conclusions: These findings contribute to our understanding of M. alba's antimicrobial properties and provide insights into the mechanisms underlying its activity against MRSA.