High value-added application of renewable natural forest product 3-carene: discovery of diacylthiosemicarbazide compounds as potential laccase inhibitors.

BACKGROUND The application of pesticides remains the most effective method for managing crop pests, weeds and diseases. However, owing to issues such as resistance to pesticides, environmental pollution, health problems and consumer demand for food safety, it is highly desirable to research and develop green and environmentally-friendly novel pesticides. RESULTS Twenty-three novel 3-carene-derived diacylthiosemicarbazide compounds were synthesized and characterized. The absolute configuration of the target compounds was also confirmed by single crystal X-ray diffraction. The tautomerization phenomenon of the target compounds was investigated using theoretical calculations. The biological activity assays showed that compounds DAT21~DAT23 not only exhibited excellent antifungal activity, but also demonstrated outstanding herbicidal activity and significant laccase inhibitory activity. The cytotoxicity results showed that compounds DAT21 and DAT23 displayed lower cytotoxicity towards three normal cells at a concentration of 10 mg L-1. The action mechanism was further conducted by molecular docking and the chelating property of the target compound with copper ion (Cu2+). CONCLUSION These results revealed that compounds DAT21~DAT23 may exert excellent pesticidal activity by inhibiting laccase. Therefore, compounds DAT21~DAT23 could serve as promising novel green pesticidal lead compounds and deserve further research. © 2025 Society of Chemical Industry.