Inhibitory effect of novel thioflavone derivatives against foodborne and spoilage microbes on fresh fruit

Abstract

AbstractIn this study, the antimicrobial activities of four thioflavones against foodborne and food spoilage bacteria (Three Gram‐positive and Five Gram‐negative bacteria) and one fungus were assessed. Antimicrobial effects of the thioflavones were evaluated using broth micro‐dilution and agar dilution assays. We generated survival curves based on the kinetics of bacterial inactivation after 24 hr of thioflavone exposure. The minimum inhibitory concentrations (MIC) for the microorganisms tested were 8–120 μg/mL. The minimum bactericidal concentrations (MBC) were 60–120 μg/mL. We evaluated three novel thioflavone derivatives and found that they exhibited strong antimicrobial activities against most of the microorganisms tested. In an in vivo antifungal study, thioflavone treatments reduced fungal decay, and 4'‐chloro‐thioflavone at a concentration of 120 μg/mL showed complete control of Rhizopus sp. in wound‐inoculated fruit.Practical applicationsThere is an urgent need for the development of new classes of antimicrobial compounds and the new thioflavone derivatives represent such a development. Thioflavones are sulfur‐containing flavones that inhibit the growth of foodborne pathogens and food spoilage microorganisms. Foodborne spoilage by bacteria or fungi cause postharvest decay and rapid deterioration, which affects the quality and shortens the shelf life of fruits and vegetables. We believe that these new thioflavone derivatives provide a viable alternative as a food preservative can extend shelf life of fruits and vegetables.