Structure-Activity Relationship of Dialkoxychalcones to Combat Fish Pathogen Saprolegnia australis

• Main Authors: Iván Montenegro, Ociel Muñoz, Joan Villena, Enrique Werner, Marco Mellado, Ingrid Ramírez, Nelson Caro, Susana Flores, Alejandro Madrid
• Format: Article
• Language: English
• Published: MDPI AG 2018-06-01
• Series: Molecules
• Subjects: 2′,4′-dihydroxychalcone; chalcones; oomycetes; Saprolegnia
• Online Access: http://www.mdpi.com/1420-3049/23/6/1377

To investigate the anti-Saprolegnia activities of chalconic compounds, nine dialkoxychalcones 2–10, along with their key building block 2′,4′-dihydroxychalcone 1, were evaluated for their potential oomycide activities against Saprolegnia australis strains. The synthesis afforded a series of O-alkylated derivatives with typical chalcone skeletons. Compounds 4–10 were reported for the first time. Interestingly, analogue 8 with the new scaffold demonstrated remarkable in vitro growth-inhibitory activities against Saprolegnia strains, displaying greater anti-oomycete potency than the standard drugs used in the assay, namely fluconazole and bronopol. In contrast, a dramatic loss of activity was observed for O-alkylated derivatives 2, 3, 6, and 7. These findings have highlighted the therapeutic potential of the natural compound 1 scaffold to be exploitable as a drug lead with specific activity against various Saprolegnia strains.