Ultrasound-assisted extraction: unlocking the antibacterial potential of Coptis chinensis Franch. Against ESBL-producing Enterobacterales

The global rise of multidrug-resistant Extended Spectrum β-Lactamase Producing-Enterobacterales (ESBL-PE) poses a critical threat to public health, driving the urgent need for alternative therapeutic approaches. This study evaluates the antimicrobial properties of 20 Chinese medicinal herbs against 14 ESBL-PE strains from seven bacterial species, utilizing three extraction methods: traditional water decoction, 80% ethanol maceration, and 50% ethanol with ultrasound-assisted extraction (UAE). Among the herbs tested, Coptis chinensis Franch. demonstrated the most potent anti-ESBL-PE activity, effectively inhibiting multiple strains, including Escherichia coli, Klebsiella pneumoniae, Hafnia alvei, Citrobacter freundii and Proteus hauseri. C. chinensis extracts obtained via UAE exhibited superior antibacterial activity to the other two extraction methods, attributed to enhanced extraction efficiency and improved bioactive compound yields. Specifically, UAE increased the extraction yield of alkaloids in C. chinensis by 80.9%, compared to the ethanol maceration method, and the increase in berberine, the key antimicrobial compound, was 75.4%. Berberine demonstrated significant antibacterial effects against ESBL-PE strains, while other phytochemicals in C. chinensis extracts have an additional effect with berberine, further amplifying the overall antimicrobial activity. These findings highlight that the UAE is a promising method for enhancing the therapeutic potential of C. chinensis and other Chinese medicinal herbs against multidrug-resistant bacteria.