Insecticidal and synergistic properties of Piper nigrum seed extracts investigated using acute toxicity assays and gene expression profiling of Drosophila melanogaster

Abstract

The overall objective of this study was to investigate the insecticidal and synergistic properties of an ethylacetate extract of Piper nigrum L. (Piperaceae) seeds used alone and in conjunction with pyrethrin, a botanical insecticide extracted from the flowers of Chrysanthemum cinerariaefolium Benth. & Hook. (Asteraceae). It was concluded that P. nigrum extract is a highly promising candidate for a novel botanical synergist for pyrethrin and could potentially be used as a replacement for piperonyl butoxide in certain pyrethrum formulations. The upregulation of mRNA transcripts encoding cytochrome P450 detoxification enzymes by a P. nigrum extract may indicate possible target proteins to enhance the toxicity of insecticides and synergists. The seven common genes differentially expressed in two or three of the sublethal treatments with pyrethrin, P. nigrum extract or pyrethrin plus P. nigrum extract merit further study of their functions relating to detoxification processes and defense responses. Future work should include a detailed, tissue-specific characterization of the genes of interest identified in this study and an investigation of the activity of the P. nigrum extract against the CYP enzymes associated with the Cyp genes that were differentially expressed in response to a P. nigrum extract. (Abstract shortened by UMI.)