Synthesis, Characterization, and Antifungal Activity of Benzimidazole-Grafted Chitosan against Aspergillus flavus

Abstract

Aspergillus flavus contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy ( 1 H and 13 C NMR). Then, the efficiency of BAC against A. flavus ACCC 32656 was investigated in terms of spore germination, mycelial growth, and aflatoxin production. BAC showed a much better antifungal effect than CS and BA. The minimum inhibitory concentration (MIC) value was 1.25 mg/mL for BAC, while the highest solubility of CS (16.0 mg/mL) or BA (4.0 mg/ mL) could not completely inhibit the growth of A. flavus. Furthermore, results showed that BAC inhibited spore germination and elongation by affecting ergosterol biosynthesis and the cell membrane integrity, leading to the permeabilization of the plasma membrane and leakage of intracellular content. The production of aflatoxin was also inhibited when treated with BAC. These findings indicate that benzimidazole-derived natural CS has the potential to be used as an ideal antifungal agent for food preservation.

Expanding the Structural Diversity of Tubulin-Targeting Agents: Development of Highly Potent Benzimidazoles for Treating Fungal Diseases

“…Carbendazim is a characteristic benzimidazole derivative and belongs to the group of tubulin-targeting agents. These benzimidazole fungicides can inhibit fungal growth by interacting with the binding site in β-tubulin protein, disrupting the spindles and, ultimately, impeding mitosis of the pathogen. − In recent years, several studies of benzimidazole derivatives in the synthesis and fungicidal/antibacterial activity have sprung up like a fountain . For example, Ahuja et al synthesized benzimidazole-1,2,4-triazoles, which were highly active against Fusarium verticillioides and Fusarium fujikuroi, with a median effective dose of 16–21 μg/mL, higher than that of the commercial fungicide carbendazim (150–230 μg/mL) .…”

Peanut Rhizosphere Achromobacter xylosoxidans Inhibits Aspergillus flavus Development and Aflatoxin Synthesis by Inducing Apoptosis through Targeting the Cell Membrane

“…Over the years, various methods have been developed to suppress A. flavus growth and aflatoxin production, including chemical fungicides and biological control agents (BCAs). − Chemical fungicides are widely used for their broad activity but face issues with resistance, toxicity, and residues . BCAs using probiotics has emerged as a promising approach due to its effectiveness, environmental friendliness, and safety profile .…”