Synthesis and evaluation of Novel Oxyalkylated derivatives of 2ʹ,4ʹ-Dihydroxychalcone as Anti-Oomycete agents against Bronopol resistant strains of Saprolegnia sp

Abstract

A series of novel oxyalkylchalcones substituted with alkyl groups were designed and synthesized, and the antioomycete activity of the series was evaluated in vitro against Saprolegnia strains. All tested O-alkylchalcones were synthesized by means of nucleophilic substitution from the natural compound 2ʹ,4ʹ-dihydroxychalcone (1) and the respective alkyl bromide. The natural chalcone (1) and 10 synthetic oxyalkylchalcones (2–11) were tested against Saprolegnia parasitica and Saprolegnia australis. Among synthetic analogs, 2-hydroxy,4-farnesyloxychalcone (11) showed the most potent activity against Saprolegnia sp., with MIC and MOC values of 125 μg/mL (similar to bronopol at 150 μg/mL) and 175 μg/mL, respectively; however, 2ʹ,4ʹ-dihydroxychalcone (1) was the strongest and most active molecule, with MIC and MOC values of 6.25 μg/mL and 12.5 μg/mL.