Plant based and synthetic products as mosquito repellents: effects, target sites and their mechanism of action on mosquitoes

Vector-borne diseases in humans occur through snails, mosquitoes, fleas, ticks, lice, sandflies, and tsetse flies infected with microbes. These comprise over 17% of all infectious diseases and significantly contribute to the burden of disease and economy. Mosquito-borne diseases account for nearly 700 million new cases and over a million deaths on an annual basis. The purpose of this review is to offer a critical analysis of mosquito repellent properties of different plants’ essential oils (pyrethrin, menthol, nicotine and rotenone) and adverse effects of synthetic repellents on different organs of animals, their mode of action, pharmacological properties, and traditional applications. DEET inhibits odorant receptors. Nicotine competitively binds with ACh receptors. Organophosphate and carbamate prevent the removal of Ach from AChE, thymol blocks the GABA-gated chloride channel, rotenone blocks the electron transport chain, and azadirachtin interferes with the synthesis of ecdysteroid and juvenile hormone. Resistance against these can be gained by mutations in some genes like kdr mutation, Ace-1R gene mutation and Rdl mutation. This review focuses on the potential of plant-based mosquito repellents as a replacement for chemical-based repellents and highlights their modes of action and relatively less or no side effects in preventing mosquito-related diseases.