Variations in polyamine conjugates in maize (Zea mays L.) seeds contaminated with aflatoxin B1: A Dose-response relationship.

Cereal seeds, such as maize seeds, are frequently contaminated with Aflatoxin B1 (AFB1), one of the most dangerous naturally occurring carcinogens. In plants, phenolamides are involved in biotic stress response. The data on variations of phenolamides in AFB1 containing seeds are limited.Five polyamine conjugates, including two spermidine and three putrescine conjugates, were tentatively identified in methanolic extracts, using HPLC-DAD-MS. The ratio of putrescine to spermidine conjugates changed with increasing AFB1 concentrations in a logistic dose-response manner, with the ratio below 1 up to the concentration of 51.51 μg/kg, and approximately 2.54 and 3 at the higher concentrations of 177.4 and 308.13 μg/kg, respectively. The observed variations of the total antioxidant activity (TAA) and the total phenolic content (TPC) may support this biphasic behavior of the seed against AFB1 stress.The obtained data are a contribution to the understanding of the roles of polyamine conjugates in the seeds' defense to the increasing AFB1 concentrations. According to our knowledge, this study reports for the first time the biphasic response of maize seeds to the increasing AFB1 contamination level, comprising the induction of the polyamine conjugates' accumulation and variation in their ratio. This dose-response relationship may provide useful information in the field of agricultural and food chemistry as an indicator of AFB1 contamination level and, hence, for selecting an appropriate seed quality. This article is protected by copyright. All rights reserved.