Plant-based insect repellents: a review of their efficacy, development and testing

Abstract

Plant-based repellents have been used for generations in traditional practice as a personal protection measure against host-seeking mosquitoes. Knowledge on traditional repellent plants obtained through ethnobotanical studies is a valuable resource for the development of new natural products. Recently, commercial repellent products containing plant-based ingredients have gained increasing popularity among consumers, as these are commonly perceived as “safe” in comparison to long-established synthetic repellents although this is sometimes a misconception. To date insufficient studies have followed standard WHO Pesticide Evaluation Scheme guidelines for repellent testing. There is a need for further standardized studies in order to better evaluate repellent compounds and develop new products that offer high repellency as well as good consumer safety. This paper presents a summary of recent information on testing, efficacy and safety of plant-based repellents as well as promising new developments in the field.

A Community-Wide Study of Malaria Reduction: Evaluating Efficacy and User-Acceptance of a Low-Cost Repellent in Northern Ghana

“…8,24 In the past few years, a plant-derived repellent, PMD has been proven to be suitably efficacious and safe to compete with DEET in the field of disease prevention, and repellents have been recognized by WHO as a useful disease prevention tool to complement insecticide-based means of vector control. 24 Insect repellents can provide protection against malaria.…”

“…8,24 In the past few years, a plant-derived repellent, PMD has been proven to be suitably efficacious and safe to compete with DEET in the field of disease prevention, and repellents have been recognized by WHO as a useful disease prevention tool to complement insecticide-based means of vector control. 24 Insect repellents can provide protection against malaria. The PMD is the only plant-based repellent that has been advocated for use in disease-endemic areas by the Centers for Disease Control (CDC), 10 because of its proven clinical efficacy to prevent malaria 25 and is considered to pose no risk to human health.…”

Repellent and mosquitocidal effects of leaf extracts of Clausena anisata against the Aedes aegypti mosquito (Diptera: Culicidae)

“…The ethanolic extract of Lippia javanica (5 mg/cm 2 ) applied topically provided 100% protection against A. aegypti for 8 hours in a laboratory study (Lukwa et al 2009). PMD applied topically at concentrations ranging from 20% to 50% gives 90 to 100% protection against various mosquito species for time periods ranging from 2h to 12h (Maia and Moore 2011). In comparison, C. anisata is appears to be a promising candidate as an ingredient of plant-based mosquito repellents.…”

“…Efforts to evaluate and develop plantbased repellents have become far more rigorous in recent years. Maia and Moore (2011) provide an extensive list of plants that have been evaluated for efficacy as mosquito repellents.…”

Microencapsulation of citronella oil by complex coacervation using chitosan-gelatin (b) system: operating design, preparation and characterization

“…However, CO was found to give 2 hours repellency and be the most effective mosquito repellent compared to the other thirty eight EOs that have been studied in [11]. Initially, CO can be as effective as DEET in repels mosquito or insect, but due to its nature, oils rapidly evaporate causing loss of efficacy and leaving the user unprotected [12].…”