The role of pickering emulsion: Improving antibacterial activity of Buddleja officinalis extracts

Buddleja officinalis Maxim , a traditional Chinese medicine, has been used for thousands of years. In this study, the antibacterial activity of Buddleja officinalis extracts (BOE) (the flavonoid extract and essential oil of B. officinalis ) was evaluated. Furthermore, a novel self-stabilized B. officinalis extract Pickering emulsion (BOEPE) was synthesized via the high-velocity homogenization method with BOE, aimed at improving the antibacterial activity of BOE. The results showed that BOE exhibited antibacterial activity, with a synergistic effect observed between flavonoid extract and essential oil. Additionally, BOEPE was successfully developed with good photostability. BOEPE demonstrated broad-spectrum antibacterial activity against 11 tested bacterial strains, including three standard bacteria, four gram-positive (G+) bacteria, and four gram-negative (G-) bacteria. Compared with flavonoids extract and essential oil, the antibacterial activity of BOEPE improved 5-100 fold and more than 15 fold, respectively. More importantly, it also enhanced antibacterial activity against drug-resistant bacteria (methicillinresistant Staphylococcus aureus (MRSA), carbapenem-resistant klebsiella pneumoniae (CRKP), and extended-spectrum β-lactamases Klebsiella pneumoniae (ESBL)). Especially for ESBL, the of BOEPE’s antibacterial efficacy was enhanced by over 500-fold compared to the flavonoids extract alone. Collectively, this study developed a potent antibacterial BOEPE formulation, which represents a promising alternative for treating infections.