Photosensitizer ability of 5-methoxysterigmatocystin isolated from aquatic fungus Acremonium persicinum

Abstract

Background: Photosensitizing ability of compounds is implicated in singlet oxygen (¹O₂) generation, a ROS nonradical able to oxidize biomolecules affecting the cellular integrity, the increase in ROS levels derived in oxidative stress that is associated to the toxicity mechanisms of mycotoxins. Herein, the photosensitizing ability to generate ¹O₂ of 5-methoxysterigmatocystin, a mycotoxin isolated from aquatic fungus Acremonium persicinum, was evaluated. Photosensitizing ability was determined through photo-oxidation of ergosterol method and corroborated by theoretical studies using Gaussian 16 programs, the M06-2X functional and the 6-311++G (d,p) basis set.

Results: 5-methoxysterigmatocystin exhibited efficient photosensitizing ability because it transformed 100% of ergosterol into ergosterol peroxide. Theoretical studies confirmed the experimental results showing that 5-methoxysterigmatocystin satisfied the energy requirements and is able to generate ¹O₂ corroborating their photosensitizing ability.

Conclusions: The identification of the photosensitizing ability of fungal compounds, such as 5-methoxysterigmatocystin and the use of visible light, could be useful in the implementation of fungi control strategies through the inactivation by self-destruction of fungi that produce photosensitizer mycotoxins in food and feed through the generation of ¹O₂ under light and thereby to contribute toward the improvement of food safety.