Solvent-dependent transformation of aflatoxin B 1 in soil

In this study, we investigated the role of the solvent vehicle in the transformation of AFB1 in soil. To do this, we spiked soils with AFB1 dissolved in water (93:7, water/methanol) or methanol and used HPLC-UV and HPLC-MS to identify the transformation products. Contrasting previous published reports, we did not detect AFB2 or AFG2. In an aqueous-soil environment, we identified aflatoxin B2a (AFB2a) as the single major transformation product. We propose that AFB2a is formed from hydrolysis of AFB1 with the soil acting as an acid catalyst. Alternatively, when methanol was used, we identified methoxy aflatoxin species likely formed via acid-catalyzed addition of methanol to AFB1. These results suggest that where soil moisture is adequate, AFB1 is hydrolyzed to AFB2a and that reactive organic solvents should be avoided when replicating natural conditions to study the fate of AFB1 in soil.
Source: Mycotoxin Research - Category: Toxicology Source Type: research