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Inhibition of Aspergillus flavus culture growth and aflatoxin accumulation in vitro by coumarin derivative

Coumarins belong to a group of organic compounds naturally occuring in many plants. They are used as food additives as well as in the drugs synthesis. Because of antifungal activities of coumarin, this study was carried out using Aspergillus flavus as a representative of pathogenic moulds, which is known to be a very potent aflatoxin producer. Aspergillus flavus can infect important food and feed crops before, during and after harvest and causes a serious economic problem worldwide. The purpose of this study was to evaluate the effect of different concentrations of coumarin derivative (11-hydroxy-7-imino-7H- 7a, 12 diazobenzo/α / antracen-6-one) on growth and aflatoxin accumulation of Aspergillus flavus ATCC 26949. Yeast extract sucrose (YES) medium was treated with various amounts of coumarin derivative after inoculation with A. flavus ATCC 26949. Experiments were carried out in a stationary culture at incubation temperature of 28oC during 21 days. At each time point mycelial dry weight was determined gravimetrically in a liquid media and the concentrations of total aflatoxins (AFT) and aflatoxin B1 (AFB1) were measured by immunochemical technique(ELISA method). The greatest amount of biomass was obtained after 21 days. The AFT and AFB1 accumulation started 7 days after inoculation and the maximum concentration was reached after 14 days. Different concentrations of coumarin derivative (0.1 and 0.2 mmol/L) partialy inhibited fungal growth and toxin acccumulation depending on the time and condition of cultivation. In the experiments with 0.3 mmol/L mould growth and accumulation of AFT and AFB1 were inhibited completely at all chosen parameters of cultivation during 21 days. This study indicates that investigated compound is na effective inhibitor of the growth of mould A.flavus ATCC 26949 and accumulation of AFT and AFB1. Antifungal and anti-aflatoxigenic activity of this compound was concentration dependent.

aflatoxins; Aspergillus flavus; coumarin; inhibition

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