Prospects for Harnessing the Rich Diversity of Phytochemical Anti-Tick Agents in Africa for the Development of Natural Acaricides

This review aims to highlight the rich biodiversity of plants with acaricidal properties in Africa and the potential for harnessing them for the development of eco-friendly acaricides. Terrestrial plant-derived bioactive substances hold huge potential as cost-effective and eco-friendly insecticides that can serve as a suitable alternative to chemical pesticides. Ticks and tick-borne diseases (TTBDs) constitute a serious challenge to animal and human health globally, necessitating the need for effective control measures. However, the use of chemical acaricides, the mainstay of tick control, is no longer sustainable due to the development of multiple acaricide resistance, economic constraints, and environmental and public health concerns, necessitating the exploration of phytochemical acaricides as a viable option. In Africa, the rich plant biodiversity remains largely underexplored and underutilized for TTBDs control. Our bibliographical review identified 144 plant species from 48 families across 27 African countries that have been assessed in various in vitro assays. These studies report that these plant species possess phytochemicals with acaricidal properties, causing over 50% mortality or repellency on various tick developmental stages. Plant species belonging to the Asteraceae (n = 23), Lamiaceae (n = 17) and Fabaceae (n = 11) from several African countries were reported to possess effective anti-tick properties. Bioactive substances and essential oils, such as the tannins, flavonoids, steroids, terpenoids, camphor, camphene, 1,8-cineole (eucalyptol), alpha-pinene and more were the most frequently isolated compounds, attesting to the rich biodiversity of plants possessing phytochemicals with strong prospects for use in tick control. Despite these encouraging findings, none so far has been translated or formulated into an anti-tick product for commercial use. Therefore, we advocate for robust continental and regional collaborations to coordinate the bioprospecting of anti-tick ethnobotanicals, ultimately leading to the development of cost-effective and eco-friendly natural products for tick control.