Study on the Antifungal Activity of Gallic Acid and Its Azole Derivatives against <i>Fusarium graminearum</i>.

Abstract

The wheat scab caused by <i>Fusarium graminearum</i> (<i>F. graminearum</i>) has seriously affected the yield and quality of wheat in China. In this study, gallic acid (GA), a natural polyphenol, was used to synthesize three azole-modified gallic acid derivatives (AGAs1-3). The antifungal activity of GA and its derivatives against <i>F. graminearum</i> was studied through mycelial growth rate experiments and field efficacy experiments. The results of the mycelial growth rate test showed that the EC₅₀ of AGAs-2 was 0.49 mg/mL, and that of AGAs-3 was 0.42 mg/mL. The biological activity of AGAs-3 on <i>F. graminearum</i> is significantly better than that of GA. The results of field efficacy tests showed that AGAs-2 and AGAs-3 significantly reduced the incidence rate and disease index of wheat scab, and the control effect reached 68.86% and 72.11%, respectively. In addition, preliminary investigation was performed on the possible interaction between AGAs-3 and <i>F. graminearum</i> using density functional theory (DFT). These results indicate that compound AGAs-3, because of its characteristic of imidazolium salts, has potential for use as a green and environmentally friendly plant-derived antifungal agent for plant pathogenic fungi.