A nanoscale γ-cyclodextrin metal-organic framework loaded with eugenol (CMFE) for controlling F. graminearum on the wheat during harvest time

The loss of grains in the production chain caused huge waste worldwide, and the control of plant pathogenic fungi during harvest time is a critical solution to mitigate the damage. Eugenol, an important component of clove oil ( Syzygium aromaticum L.), has antioxidant, antifungal, and other activities. In this study, the unstable eugenol was incorporated into the nanoscale γ-cyclodextrin metal-organic framework (γ-CD-MOF), a cubic porous structure synthesized by vapor diffusion method. The investigation of morphologies, functional groups, crystalline structures and weight losing behaviors demonstrated the inclusion complex prepared from γ-CD-MOF and eugenol (CMFE). Compared with the γ-CD loaded with eugenol (CE), CMFE exhibited an improved loading rate with 4.06 % ( w/w ). And CMFE enhanced the stability of its inner eugenol against degradation by light and air. Moreover, the CMFE demonstrated a significant anti -F. graminearum activity both in the medium and on the wheat grains. The inhibition rate reached 83.8 % at 8 mg/mL in vitro , while the growth of the hyphae was effectively restrained at 4 mg/g in vivo . CMFE could damage the mycelial cell wall and trigger intracellular reactive oxygen species (ROS) accumulation, thus exhibiting its anti- F. graminearum activity. Our results showed that the biocompatible CMFE would be an environment-friendly substitute to chemical fungicides for the prevention of fungal contamination caused by F. graminearum .