Molecular Targets for Components of Essential Oils in the Insect Nervous System—A Review

Abstract

Essential oils (EOs) are lipophilic secondary metabolites obtained from plants; terpenoids represent the main components of them. A lot of studies showed neurotoxic actions of EOs. In insects, they cause paralysis followed by death. This feature let us consider components of EOs as potential bioinsecticides. The inhibition of acetylcholinesterase (AChE) is the one of the most investigated mechanisms of action in EOs. However, EOs are rather weak inhibitors of AChE. Another proposed mechanism of EO action is a positive allosteric modulation of GABA receptors (GABArs). There are several papers that prove the potentiation of GABA effect on mammalian receptors induced by EOs. In contrast, there is lack of any data concerning the binding of EO components in insects GABArs. In insects, EOs act also via the octopaminergic system. Available data show that EOs can increase the level of both cAMP and calcium in nervous cells. Moreover, some EO components compete with octopamine in binding to its receptor. Electrophysiological experiments performed on Periplaneta americana have shown similarity in the action of EO components and octopamine. This suggests that EOs can modify neuron activity by octopamine receptors. A multitude of potential targets in the insect nervous system makes EO components interesting candidates for bio-insecticides.

Essential Oils in Stored Product Insect Pest Control

“…Several research studies showed neurotoxic actions of EOs, causing insect paralysis followed by death (reviewed by [129]). Among mechanisms of action, the inhibition of acetylcholinesterase (AChE) is one of the most investigated in stored product pests.…”

“…Overall, EOs are generally supposed to act as neuroinsecticides, and their insecticidal activity is considered species-dependent [129]. For this reason, in insects, other proposed mechanisms of EO action include the inhibition of GABA receptors (GABArs) and the alteration of the octopaminergic system.…”

Plodia interpunctella (Lepidoptera: Pyralidae): Intoxication with essential oils isolated from Lippia turbinata (Griseb.) and analysis of neuropeptides and neuropeptide receptors, putative targets for pest control

“…A possible avenue in the development of novel compounds is the research in botanical pesticides. They have many advantages over synthetic insecticides, such as high selectivity, low, or no toxicity to vertebrates and the environment, rapid degradation, low residue levels, and novel modes of action (Jankowska, Rogalska, Wyszkowska, & Stankiewicz, 2018; Phillips & Throne, 2009). However, in most cases, the mechanisms of action and physiological targets of botanical pesticides remain unknown.…”

“…The Indian meal moth Plodia interpunctella (Hübner, 1813; Lepidoptera: Pyralidae) is a major economic pest of stored products worldwide (Johnson, 2013; Mohandass, Arthur, Zhu, & Throne, 2007). P. interpunctella has been the subject of some studies on the toxic effects of essential oils (EOs), even though the mode of action of these products has not been clarified to date (Borzoui, Naseri, Abedi, & Karimi‐Pormehr, 2016; E. S. B. Cavalcanti, Morais, Lima, & Santana, 2004; Jankowska et al, 2018; Zamani, 2011).…”

Physically acting products for head lice – the end of the beginning

“…Despite repeated reports of treatment failure, and even attempts at litigation through class action by frustrated consumers (Williams, McIntyre & Pilitere, 2001), most pediculicide manufacturers failed to take positive action to address the problems, relying in some cases on historical data to support efficacy (Vander Stichele, Dezeure & Bogaert, 1995); professional assessments that suggested method or thoroughness of application technique influenced treatment outcome more than physiological tolerance (Aston, Duggal & Simpson, 1998); or specific formulations that showed better efficacy in some geographic regions (Bialek, Zelck & Fölster-Holst, 2011;Byrne, 1988;Mills et al, 2004;Miyazawa & Yamafuji, 2005;Jankowska et al, 2018).…”