Synthesis of Novel Imidazole Derivatives Based on Camalexin Scaffold and Anti-fungal Activity against Rice Blast

Aims: Rice blast disease (RBD), which is caused by the pathogenic fungi of Magnaporthe oryzae is the most devastating diseases of cultivated rice (Oryza sativa L) Although many strategies have been applied to control the RBD, chemical anti-fungal agents are the most effective solutions to minimize the severity of RBD. The aim of this study is to explore new anti-fungal agents for RBD control.
Study Design: Natural products are important source of biological active compounds. We used camalexin (3-thiazol-2’-yl-indole), which is a well known phytoalexin of Arabidopsis thaliana. In the present work, we designed new imidazoles based on camalexin as a molecular scaffold and the anti-fungal activity of the synthesized compounds against Magnaporthe oryzae were determined.
Place and Duration of Study: All the experiments were conducted from October 2014 to March 2015 at Akita Prefectural University, Japan.
Methodology: A series of new imidazole derivatives was designed and synthesized based on the camalexin as a molecular scaffold. The antifungal activity of the synthesized compounds against Magnaporthe oryzae was determined by using in vitro mycelial growth inhibition tests.
Results: Among 3 newly synthesized camalexin based imidazole compounds, we found that 3-[3-(1H-imidazol-1-yl)propyl]-1H-Indole (2c) exhibits potent inhibitory activity with an IC50 value approximately 7.8±1.2 μM.
Conclusion: We discovered a new lead compound with potent activity for rice blast control.