Potential of Essential Oil-Based Anticholinesterase Insecticides against Anopheles Vectors: A Review

Abstract

The insect nervous system is critical for its functional integrity. The cholinergic system, of which acetylcholinesterase (AChE) is a key enzyme, is essential to the Anopheles (consisting of major malaria vector species) nervous system. Furthermore, the nervous system is also the primary target site for insecticides used in malaria vector control programs. Insecticides, incorporated in insecticide-treated nets and used for indoor residual spraying, are a core intervention employed in malaria vector control. However, Anopheles resistance against these insecticides has grown rapidly. Due to this major setback, novel agents with potential activity against resistant Anopheles and/or capacity to overcome resistance against current WHO-approved insecticides are urgently needed. The essential oils have the potential to be natural sources of novel insecticides with potential to inhibit the Anopheles AChE target. In the current review, the scientific evidence highlights the ability of essential oils and specific essential oil constituents to serve as anticholinesterase insecticides. For this reason, the published data from scientific databases on the essential oils and essential oil constituents on anticholinesterase, ovicidal, larvicidal, pupicidal and adulticidal activities were analyzed. The identification of major constituents in active essential oils and their possible influence on the biological activity have also been critically evaluated. Furthermore, the toxicity to mammals as well as potential activity against the mammalian AChE target has also been reviewed. The importance of identifying novel potent insecticides from essential oils has been discussed, in relation to human safety and cost-effectiveness. Finally, the critical insights from this review can be used to inform future researchers towards potent and safe anticholinesterase insecticides for the management of Anopheles malaria vectors.

Larvicidal, Ovicidal, and Repellent Activities of Leucas stachydiformis (Hochst. ex Benth.) Briq Essential Oil against Anopheles arabiensis

“…Diferent phytochemicals are known to cause neurotoxicity or direct contact toxicity to the midgut epithelium of mosquito larvae [34]. In the present study, the identifed essential oil constituents such as caryophyllene oxide, α-pinene, and linalool are known to have antiacetylcholinesterase activity [5], whereas α-terpineol was reported to have an infuence on the production of cyclic adenosine monophosphate (cAMP) and calcium at the cellular level and these efects consequentially lead to larval death [35].…”

“…In this regard, community-based long-lasting insecticidal nets (LLINs) and larval source management (LSM) have been the mainstay in vector control eforts [4]. However, these synthetic insecticidebased methods are threatened because of widespread resistance to all currently used insecticides by mosquitoes, and their negative efect on the nontarget organisms and the ecosystem [5]. Tese problems may lead to renewed malaria outbreaks and deaths from insecticidal poisoning.…”

Toxic Effects of Perilla frutescens (L.) Britt. Essential Oil and Its Main Component on Culex pipiens pallens (Diptera: Culicidae)

“…Being a mixture of components, essential oils are complex and may have multiple larvicidal mechanisms acting in combination that have not been elucidated [ 19 ]. Some studies have demonstrated that essential oils inhibit acetylcholinesterase, causing neurotoxicity and leading to larval mortality [ 20 ]. In the present study, we measured the acetylcholinesterase activity of larvae after treatment with LC50 of perilla essential oil and 2-hexanoylfuran but found no change ( Figure S2 in Supplementary Materials ).…”

Targeting Aedes aegypti Metabolism with Next-Generation Insecticides

“…Identifying insecticide activity in natural products has been a strong focus of recent research, including characterization of components in essential oils, seaweed, botanicals, and medicinal plants [ 57 , 58 , 59 , 60 , 61 ]. Studies have also shown efficacy targeting specific tissues and metabolic pathways, with a focus on new mechanisms of action and avoiding off-target effects.…”