Synthesis and Pesticidal Activities of Ester Derivatives of the Labdane Diterpenoid Andrographolide at the C-3 Position Containing the Isoxazoline Fragment and Their Toxicology Study against Boisduval.

Due to the long-term overuse of chemical pesticides, serious resistance and negative problems on human health and the ecological environment have appeared. To develop plant-product-based pesticide candidates, a series of novel andrographolide ester derivatives containing the isoxazoline skeleton were prepared at the C-3 position. Their pesticidal activities were evaluated against three typical pests such as Walker, Van der Goot, and Boisduval. Against . , compounds , , , and showed 1.6-1.8 times insecticidal activity compared to that of andrographolide; against . , compounds , , and possessed 3.7-3.9-fold aphicidal activity compared to that of andrographolide; against . , compounds , , and exhibited 7.4-9.1-fold promising acaricidal activity compared to that of andrographolide. It is worth mentioning that effects of on morphological changes of the treated mite cuticle layer structures were observed by the scanning electron microscope imaging method. Compound can be studied as a pesticidal lead for further structural modification.