Gaire Sudip, Zheng Wei, Scharf Michael E, Gondhalekar Ameya D
Center for Urban and Industrial Pest Management, Department of Entomology, Purdue University, West Lafayette, IN 47907, USA; Department of Entomology, University of Kentucky, Lexington, KY 40546, USA.
School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA.
Pestic Biochem Physiol. 2021 Jun;175:104829. doi: 10.1016/j.pestbp.2021.104829. Epub 2021 Mar 20.
Plant essential oils (EOs) are secondary metabolites derived from aromatic plants that are composed of complex mixtures of chemical constituents. EOs have been proposed as one of the alternative methods for bed bug (Cimex lectularius L.) control. In insecticide resistant mosquitoes and tobacco cutworm, EOs synergize pyrethroid toxicity by inhibiting detoxification enzymes. However, whether EOs and their constituents enhance pyrethroid toxicity in C. lectularius has remained unknown. Therefore, this study was designed to (i) determine the effects of binary mixtures of deltamethrin (a pyrethroid insecticide) with EOs or EO constituents or EcoRaider® (an EO-based product) on mortality of insecticide resistant and susceptible bed bugs, and (ii) evaluate the effects of EO constituent pre-treatment on detoxification enzyme activities of resistant and susceptible populations. Topical bioassays with binary mixtures of deltamethrin and individual EOs (e.g., thyme, oregano, clove, geranium or coriander oils) or their major constituents (e.g., thymol, carvacrol, eugenol, geraniol or linalool) or EcoRaider® at doses that kill approximately 25% of bed bugs caused significant increases in mortality of resistant bed bugs. However, in the susceptible population, only coriander oil, EcoRaider®, thymol, and carvacrol significantly increased the toxicity of deltamethrin. Detoxification enzyme assays with protein extracts from bed bugs pre-treated with EO constituents suggested selective inhibition of cytochrome P450 activity in the resistant population, but no impacts were observed on esterase and glutathione transferase activities in either population. Inhibition of P450 activity by EO constituents thus appears to be one of the mechanisms of deltamethrin toxicity enhancement in resistant bed bugs.
植物精油（EOs）是从芳香植物中提取的次生代谢产物，由化学成分的复杂混合物组成。精油已被提议作为控制臭虫（温带臭虫）的替代方法之一。在抗杀虫剂的蚊子和烟草夜蛾中，精油通过抑制解毒酶来增强拟除虫菊酯的毒性。然而，精油及其成分是否能增强臭虫体内拟除虫菊酯的毒性仍不清楚。因此，本研究旨在：（i）确定溴氰菊酯（一种拟除虫菊酯类杀虫剂）与精油、精油成分或EcoRaider®（一种基于精油的产品）的二元混合物对具有抗药性和易感性的臭虫死亡率的影响；（ii）评估精油成分预处理对耐药和敏感种群解毒酶活性的影响。用溴氰菊酯与单一精油（如百里香、牛至、丁香、天竺葵或芫荽油）或其主要成分（如百里酚、香芹酚、丁香酚、香叶醇或芳樟醇）或EcoRaider®的二元混合物进行局部生物测定，在能杀死约25%臭虫的剂量下，显著提高了抗药性臭虫的死亡率。然而，在易感种群中，只有芫荽油、EcoRaider®、百里酚和香芹酚显著增加了溴氰菊酯的毒性。用精油成分预处理的臭虫蛋白质提取物进行解毒酶测定，结果表明，抗性种群中的细胞色素P450活性受到选择性抑制，但在这两个种群中均未观察到对酯酶和谷胱甘肽转移酶活性的影响。因此，精油成分对P450活性的抑制似乎是抗性臭虫中溴氰菊酯毒性增强的机制之一。
