Non-food bioactive products: Semisynthesis, biological activities, and mechanisms of action of oximinoether derivatives of matrine from Sophora flavescens

Abstract

Matrine, a quinolizidine alkaloid isolated from the roots of Sophora flavescens, is a naturally non-food bioactive product. To discover new non-food bioactive product-based pesticides, a series of 15-chloro-18-oximinoether derivatives of matrine were prepared by structural modifications of matrine. Compounds 7 m, 7o, 7q, 7 s, and 7 t display potent insecticidal activity against Mythimna separata Walker. Compounds 7b (R2 = n-butyl) and 7 l (R2 = p-methylbenzyl) exhibit greater than 6 folds more pronounced acaricidal activity than matrine against Tetranychus cinnabarinus Boisduval. Through reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time polymerase chain reaction (qRT-PCR) analysis, it is found that introduction of the chlorine atom and the oximinoether moiety at the C-15 and C-18 positions of matrine is important for acting with nAChR α1, α2 and α4 subunits in T. cinnabarinus; α1, α2, α4 and β3 subunits may be the target of action of compound 7b against T. cinnabarinus; structural modification on the lactam ring of compound 1 can lead to the change of mode of action on VGSC in T. cinnabarinus.