Dental caries and pulpal diseases are common oral bacterial
infectious diseases. Controlling and reducing the causative pathogens, such as Streptococcus mutans and Enterococcus faecalis, is a key step toward prevention and treatment of the two diseases.
Chrysophsin-1 is a
cationic antimicrobial peptide having broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. In this study, we investigated the antibacterial activity of
chrysophsin-1 against several oral pathogens and S. mutans biofilms and performed a preliminary study of the antimicrobial mechanism. Cytotoxic activity of
chrysophsin-1 against human gingival fibroblasts (HGFs) was investigated. Minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and time-kill assay were used to evaluate the killing effect of
chrysophsin-1. Scanning electron microscopy (SEM) was used to analyze morphological and membrane change in oral pathogens. Live/Dead staining, in conjunction with confocal scanning
laser microscopy (CSLM), was used to observe and analyze S. mutans biofilms. MIC and MBC results demonstrated that
chrysophsin-1 had different antimicrobial activities against the tested oral microbes. Lysis and pore formation of the cytomembrane were observed following treatment of the bacteria with
chrysophsin-1 for 4h or 24h by SEM. Furthermore, CLSM images showed that
chrysophsin-1 remarkably reduced the viability of cells within biofilms and had a significantly lethal effect against S. mutans biofilms. Toxicity studies showed that
chrysophsin-1 at concentration between 8 μg/ml and 32 μg/ml had little effect on viability of HGFs in 5 min. Our findings suggest that
chrysophsin-1 may have potential clinical applications in the prevention and treatment of
dental caries and pulpal diseases.