Inhibition of Aflatoxin Biosynthesis by Organophosphorus Compounds.

Area of Science:

• Mycology
• Organic Chemistry
• Biochemistry

Background:

• Aflatoxins are toxic secondary metabolites produced by Aspergillus flavus, posing significant risks to food safety and human health.
• Understanding the biosynthesis pathways of aflatoxins is crucial for developing effective control strategies.

Purpose of the Study:

• To investigate the impact of various organophosphorus compounds and other chemicals on aflatoxin production by Aspergillus flavus.
• To identify novel compounds that can inhibit aflatoxin biosynthesis and elucidate their mechanisms of action.

Main Methods:

• Exposure of Aspergillus flavus cultures to different concentrations (20 and 100 μg/ml) of organophosphorus compounds and other chemicals.
• Analysis of aflatoxin levels and pigment formation using chromatographic and spectroscopic techniques.
• Structural elucidation of newly identified pigments.

Main Results:

• Five organophosphorus compounds (Chlormephos, Ciodrin, Naled, Phosdrin, Trichlorphon) demonstrated Dichlorvos-like activity, reducing aflatoxin production and inducing anthraquinone pigment formation.
• Two novel anthraquinone pigments, Versicol and its acetate derivative, were identified and characterized.
• Ammonium nitrate and Tridecanone also exhibited Dichlorvos-type activity, suggesting a broader range of inhibitory compounds.
• Tridecanone's activity is likely due to competitive inhibition of enzymes in the aflatoxin biosynthesis pathway.

Conclusions:

• Certain organophosphorus compounds and other chemicals can effectively inhibit aflatoxin production in Aspergillus flavus.
• The observed inhibition may be linked to the disruption of key enzymes in aflatoxin biosynthesis, potentially through mechanisms like competitive inhibition.
• The identification of novel pigments provides further insight into the biochemical processes affected by these compounds.