Baicalin: Natural Sources, Extraction Techniques, and Therapeutic Applications Against Bacterial Infections

The emergence of bacterial strains resistant to available antibiotics due to overprescription has prompted a search for alternative treatments. Among the most promising is baicalin, a flavonoid extracted from the roots of Scutellaria baicalensis. Roots, the primary natural source of baicalin, have been extensively explored using emerging extraction technologies such as ultrasonic-assisted extraction and supercritical fluid extraction. These methods offer significant advantages over traditional reflux extraction for baicalin preparation, including shorter extraction times, lower energy consumption, and improved environmental sustainability. Baicalin exhibits remarkable antibacterial activity in vitro and has demonstrated therapeutic efficacy against gastrointestinal infections, meningitis, pulmonary diseases, and sepsis, among other infectious disorders, in animal models. Documented mechanisms of action include disrupting the Escherichia coli membrane, downregulating quorum-sensing gene expression in Pseudomonas aeruginosa, and inhibiting host inflammatory pathways such as PI3K/Akt/NF-κB. However, its clinical translation faces several bottlenecks, including reliance on animal experiment data, low bioavailability, and regulatory compliance issues. This review compares baicalin extraction yields from different natural sources, summarizes the advantages and disadvantages of various extraction technologies, analyzes possible mechanisms of action in treating different bacterial diseases, and discusses outstanding challenges and best strategies for expanded clinical use against bacterial infection. Our aim is to provide a valuable reference for future research and clinical applications.