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Shikonin has anticancer, anti-inflammatory, and wound healing activities. Vibrio vulnificusis an important marine foodborne pathogen with a high fatality rate and rapid pathogenesis that can infect humans through ingestion and wounds. In this study, the antibacterial activity and possible antibacterial mechanism of shikonin against V. vulnificuswere investigated. In addition, the ability of shikonin to control V. vulnificusinfection in both pathways was assessed by artificially contaminated oysters and full-thickness excised skin-infected mice. Shikonin treatment can cause abnormal cell membrane function, as evidenced by hyperpolarization of the cell membrane, significant decreased intracellular ATP concentration (p< 0.05), significant increased intracellular reactive oxygen species and malondialdehyde content (p< 0.05), decreased cell membrane integrity, and changes in cell morphology. Shikonin at 40 and 80 μg/mL reduced bacterial numbers in shikonin-contaminated oysters by 3.58 and 2.18 log colony-forming unit (CFU)/mL. Shikonin can promote wound healing in mice infected with V. vulnificusby promoting the formation of granulation tissue, hair follicles, and sebaceous glands, promoting epithelial cell regeneration and epidermal growth factor production. These findings suggest that shikonin has a strong inactivation effect on V. vulnificusand can be used in food production and wound healing to effectively control V. vulnificusand reduce the number of diseases associated with it.

Eugenol is a natural active substance with high antibacterial activity, but its antibacterial activity against Vibrio vulnificushas not been extensively studied. The purpose of this study was to investigate the antibacterial and biofilm-clearing abilities and potential mechanisms of eugenol against V. vulnificus, and to provide knowledge for the use of eugenol to prevent oyster contamination. It was found that eugenol had an encouraging antibacterial effect on V. vulnificuswith a minimum inhibitory concentration (MIC) of 0.2 mg/mL. The accumulation of reactive oxygen species (ROS) and the increase of malondialdehyde (MDA) content suggest that oxidative stress is involved in the bactericidal mechanism. Moreover, cell membrane hyperpolarization, changes in cell membrane integrity and morphology suggest that eugenol can reduce the permeability and integrity of cell membranes in V. vulnificus. In addition, eugenol produced a significant biofilm clearance effect on V. vulnificus, as evidenced by the reduced amount of biofilm and the reduction of polysaccharides and viable cells in the biofilm. Finally, eugenol was able to effectively inhibit the activity of V. vulnificusin artificially contaminated oyster at 4 °C and 25 °C. But sensory analysis showed that 0.10% eugenol was most acceptable to trained panelists. All of these highlight the great promise of eugenol as a natural bacteriostatic agent for the food industry.