Biological Activity Evaluation of Natural Carbon Dots Against <i>Clostridium perfringens</i>

Clostridium perfringens is known to cause intestinal infections in both humans and poultry, highlighting the importance of identifying highly effective, low-toxicity natural products for treating necrotic enteritis (NE) caused by this bacterium. This study aimed to identify carbon dots (CDs), derived from natural products with the most potent antibacterial effect against C. perfringens, optimize their preparation conditions, and characterize them structurally and compositionally. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the microdilution method. To further investigate the antibacterial mechanism in vitro, time-kill curves were generated, and experiments were conducted to assess protein and nucleic acid leakage. The results demonstrated that the selected Phellodendri chinensis cortex carbon dots (PCC-CDs) effectively damaged the cell membrane of C. perfringens, leading to the leakage of proteins and nucleic acids after 8 h of co-incubation. In addition, PCC-CDs exhibited comparable antibacterial activity to amoxicillin over this period. The antioxidant activity of PCC-CDs was also evaluated, revealing their excellent antioxidant properties. In conclusion, PCC-CDs demonstrate both strong antibacterial activity against C. perfringens and superior antioxidant capacity. This study presents a novel approach for the development and application of traditional Chinese medicine (TCM) resources, offers a theoretical foundation for future research on antibiotic alternatives, and lays the groundwork for innovative applications in natural products.