LAUSR

BACKGROUND Paeonol is extracted and isolated as a rich and sustainable natural bioresource from the root bark of Paeonia suffruticosa, the derivatives of which exhibit numerous biological activities. It is well known that ester compounds play a very important role in pest control, such as organophosphorus, carbamate and pyrethroid pesticides. RESULTS To discover biorational natural product-based pesticides, three series of (60) paeonol ester derivatives (7a-t, 8g,p, 9g,p, 10g-j,n-u, 11g,u, 12g,u, 13a-p, 14b,c, and 15b,c) were prepared by structural modification of paeonol, and their structures were well characterized by 1 H NMR, 13 C NMR, HRMS, and melting point. Furthermore, we assessed the compounds as insecticidal, nematicidal, and anti-oomycete agents against three serious agricultural pests, Mythimna separata, Heterodera glycines, and Phytophthora capsici. Among all tested compounds, 1) Compound 8p showed more significant insecticidal activity than toosendanin, and the final mortality rates of 8p and toosendanin against M. separata (1 mg/mL) were 70.4%, and 51.9%, respectively; 2) Compound 7a exhibited more promising nematicidal activity than paeonol, and the LC50 values of 7a and 1 against H. glycines were 15.47 and 50.80 mg/L, respectively; 3) Compounds 7n and 13m displayed more significant anti-oomycete activity compared to zoxamide against P. capsici, and the EC50 values of 7n, 13m, and zoxamide were 23.72, 24.51, and 26.87 mg/L, respectively; and the protective effect of the compounds against P. capsici in vivo further confirmed the effectiveness of the agents. CONCLUSION This study suggested that the introduction of a nitro at the C5 or C3 position of paeonol could improve its bioactivity against M. separata, H. glycines, and P. capsici. This article is protected by copyright. All rights reserved.