[Synthesis of copper nanocomposite particles with Lonicerae Japonicae Flos aqueous extract and evaluation of their antibacterial and anti-inflammatory activities].

The objective of this study is to synthesize nanocomposite particles(HCuNPs) with the aqueous extract of Lonicerae Japonicae Flos and copper ions by a green one-step self-assembly method and to investigate their antibacterial activity, antibacterial mechanism, and anti-inflammatory activity. The particle size, appearance, and properties of HCuNPs were characterized by transmission electron microscopy and ultraviolet spectrophotometry. The antibacterial activity of HCuNPs was evaluated by the growth curve method and the spread plate method. The antibacterial mechanism was investigated by bacterial structure disruption, leakage of nucleic acids and proteins, reactive sulfhydryl group activity, and in vitro reactive oxygen species experiments. The antioxidant activity was investigated via the DPPH and the ABTS free radical scavenging assays. The cytotoxicity was evaluated by the cell viability assay, and the anti-inflammatory activity was investigated by in vitro anti-inflammatory experiments. The results showed that the particle size of HCuNPs synthesized by self-assembly with the aqueous extract of Lonicerae Japonicae Flos and copper ions was approximately(19.47±0.77) nm, and the particles were well-dispersed. Moreover, HCuNPs showed strong antibacterial activities against Pseudomonas aeruginosa, Staphylococcus aureus, vancomycin-intermediate S. aureus, and methicillin-resistant S. aureus. HCuNPs can promote the burst of reactive oxygen species in bacteria by consuming or interfering with the sulfhydryl substances required during the growth process of bacteria, thereby destroying the bacterial structure and causing the leakage of contents, resulting in the death of bacteria. Furthermore, HCuNPs can eliminate DPPH free radicals and ABTS free radicals, and enhance the anti-inflammatory ability of cells by reducing the secretion levels of inflammatory factors tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6). In this study, the self-assembled HCuNPs demonstrated stronger antibacterial activity than both the aqueous extract of Lonicerae Japonicae Flos and the copper ions individually.