In silico chemical library screening and experimental validation of novel compounds with potential varroacide activities

Abstract The mite Varroa destructor is an ectoparasite and has been identified as a major cause of worldwide honey bee colony losses. The use of yearly treatments for the control of varroosis is the most common answer to prevent collapses of honey bee colonies due to the mite. However, the number of effective acaricides is small and the mite tends to become resistant to these few active molecules. In this study, we have been looking for a new original varroacide treatment inhibiting selectively Varroa destructor AChE ( vd AChE) with respect to Apis mellifera AChE ( am AChE). To do this an original drug design methodology was used applying virtual screening of the CERMN chemolibrary, starting from a vd AChE homology sequence model. By combining the in silico screening with in vitro experiments, two promising compounds were found. In vitro tests of AChE inhibition for both species have confirmed good selectivity toward the mite vd AChE. Moreover, an in vivo protocol was performed and highlighted a varroacide activity without acute consequences on honey bee survival. The two compounds discovered have the potential to become new drug leads for the development of new treatments against the mite varroa. The method described here clearly shows the potential of a drug-design approach to develop new solutions to safeguard honey bee health.