New Hit Compounds Targeting Odorant Binding Proteins (OBPs) as Putative Repellents

Mosquitoes are responsible for the transmission of serious and potentially fatal diseases to humans, such as malaria, dengue fever, West Nile fever, leishmaniasis and more recently Zika virus[1] infection. According to the World Health Organization, the prevalence of human mortality causing from infected mosquitoes amounts to one million, annually.[2,3] Nowadays, the increasing resistance of vectors to existing repellents render them as ineffective, creating the need for development of novel repellents with advanced properties to the existing ones in terms of duration of the protection, minimum effective dose, efficacy against a wide variety of insects’ bites and safety. The main goal of the current study is the discovery of novel hit compounds which may evolve as insect repellents by performing a combination of computational and analytical chemistry methodologies. Particularly, a pharmacophore-based virtual screening of natural compound libraries coupled with molecular docking were applied to identify novel hits towards Odorant Binding Protein 1 (OBP1) a molecular target for the most widely used synthetic repellents DEET[4,5] and Icaridin[6]. Compounds were selected to bear the appropriate physicochemical properties associated with insect repellency. Six compounds were evaluated against female mosquitoes (Aedes albopictus). Results presented insect repellent activity of 35-57,9% compared to untreated hand which indicate the proposed scaffolds as starting points for further structure optimization. References [1] G. S. Rawal et al., J Family Med Prim Care 2016, 5, 523-527. [2] R. Lozano et al., Lancet 2012, 380, 2095-2128. [3] World Health Organization. Vector-borne diseases fact sheet N. 387. WHO website http://www.who.int/mediacentre/factsheets/fs387/en/ WHO, 2016 [4] K. E. Tsitsanou et al., Cell Mol Life Sci 2012, 69, 283-297. [5] S. E. Zografos et al., ''QSAR in Environmental and Health Sciences", 65-99. [6] C. E. Drakou et al., Cell Mol Life Sci 2017, 74, 319-338.  Acknowledgements This study was supported by “IKY FELLOWSHIPS OF EXELLENCE FOR POSTGRADUATE STUDIES IN GREECE-SIEMENS PROGRAM”.