Given the increasing concern regarding antibacterial resistance, the antimicrobial properties of naphthoquinones have recently attracted significant attention. While 1,4-naphthoquinone and its derivatives have been extensively studied, the antibacterial properties of 5,8-dihydroxy-1,4-naphthoquinone derivatives remain relatively unexplored. This study presents a comprehensive in vitro and in vivo analysis of the antibacterial activity of 35 naturally sourced and chemically synthesized derivatives of 5,8-dihydroxy-1,4-naphthoquinone. Kirby-Bauer antibiotic testing identified three compounds with activity against methicillin-resistant Staphylococcus aureus (MRSA), with one compound (PNP-02) demonstrating activity comparable to vancomycin in minimum inhibitory concentration, minimum bactericidal concentration (MBC), and time-kill assays. Microscopic and biochemical analyses revealed that PNP-02 adversely affects the cell wall and cell membrane of MRSA. Mechanistic investigations, including proteomic sequencing analyses, Western blotting, and RT-qPCR assays, indicated that PNP-02 compromises cell membrane integrity by inhibiting arginine biosynthesis and pyrimidine metabolism pathways, thereby increasing membrane permeability and inducing bacterial death. In an in vivo mouse model of skin wound healing, PNP-02 exhibited antibacterial efficacy similar to vancomycin. The compound demonstrated low toxicity to cultured human cells and in hemolysis assays and remained stable during serum incubation. These findings suggest that PNP-02 possesses promising bioactivity against MRSA and represents a potential novel antibacterial agent.
Methicillin-Resistant Staphylococcus aureus/genetics* ; Anti-Bacterial Agents/chemistry* ; Naphthoquinones/administration & dosage* ; Animals ; Microbial Sensitivity Tests ; Mice ; Humans ; Staphylococcal Infections/microbiology* ; Molecular Structure

This study is to investigate the mechanism of human promyelocytic leukemia HL-60 cells proliferation induced by alteronol in vitro. Human promyelocytic leukemia HL-60 cells cultured in vitro were treated with different concentrations of alteronol. Inhibition rate was detected by SRB assay. Cellular morphological changes were observed by Hoechst and AO/EB (acridine orange/ethidium bromide dye) staining. The apoptosis rate was determined by Annexin V-FITC/PI assay. Cell cycle distribution was determined by flow cytometry. Western blotting analysis was carried out to determine the cell cycle related proteins. The proliferation of HL-60 cells treated with alteronol was inhibited in a concentration-dependent manner. Based on cell viability assay, observation on cell morphology and apoptosis rate, it confirmed that alteronol played an obvious role in proliferation inhibition of human promyelocytic leukemia HL-60 cells, but it did not induce apoptosis in human promyelocytic leukemia HL-60 cells in different concentrations groups. Alteronol could effectively inhibit the proliferation of human promyelocytic leukemia HL-60 cells inducing cell cycle arrest at G1 phase, as well as, alteration expression of cell cycle proteins level of CyclinD1 and pRb.
Antineoplastic Agents ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cyclin D1 ; metabolism ; Dose-Response Relationship, Drug ; HL-60 Cells ; Humans ; Naphthoquinones ; administration & dosage ; pharmacology ; Phosphorylation ; Retinoblastoma Protein ; metabolism