DFT STUDY OF THE ELECTRONIC STRUCTURE AND BONDING ORBITALS OF AFLATOXIN B1

Abstract

This study presents a comprehensive analysis of the electronic structure of the aflatoxin B1 molecule, performed using modern quantum chemical methods. Aflatoxin B1 is a secondary metabolite produced by certain species of microscopic mold fungi of the genus Aspergillus (Aspergillus flavus, A. parasiticus). The primary objective of the study was the application of two highly effective tools: density functional theory (DFT with the B3LYP/3-21G calculation level) and natural bonding orbital (NBO) analysis. These approaches enable a detailed study of the electron density distribution within the molecule, revealing a high degree of electron delocalization extending all the way to the inner layers of carbon atoms. This effect is due to strong donor-acceptor interactions, which contribute to the increased stability of the molecule. A key achievement was the discovery of a vulnerable region of the molecule – the lactone bond O4-C23, characterized by pronounced polarization. This bond acts as a “weak link” that determines the increased reactivity of aflatoxin B1. It is this region that exhibits particular activity, playing a key role in the mechanisms of aflatoxin B1's toxic effects. Understanding the structural features of the molecule allows for a more in-depth study of its interactions with cellular components, particularly with gluten proteins in grain crops. The data obtained hold great potential for developing methods to protect food products from mycotoxin contamination, ensuring the biosafety of the final product. The results of this study significantly contribute to fundamental knowledge of the structure and function of aflatoxin B1, enabling the development of new strategies to combat this dangerous contamination of food resources/