The plant family Piperaceae contains several members with high levels of isobutyl amides. These compounds have been shown to inhibit PSMO activity in mammalian enzyme systems. The use of Musca domestica and Periplaneta americana in vitro microsomal enzyme assays (MROD) has for the first time indicated that inhibition also occurs with the main black pepper Piper nigrum constituent, piperine. The relative importance of this activity in the chemical defence of the plant is apparent since the enzyme activity in the insect controls crucial stages of development. Another important element of the PSMO inhibition and a unique target site is that there is little difference between the toxicity of pesticide resistance versus susceptible Leptinotarsa decemlineata. Further toxicokinetic trials with P. americana indicate that piperine has a short residual time in the insect, but the molecule targets specific organs such as the nerve cord.
Species 1: Orthoptera Blattidae Periplaneta americana (American cockroach)
Species 2: Diptera Muscidae Musca domestica (house fly)
Species 3: Coleoptera Chrysomelidae Leptinotarsa decemlineata (Colorado potato beetle)
Keywords: insecticidal activity, Piperaceae
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