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In the current study, four organic solvents, including ethanol, methanol, acetone, and diethyl ether, were used to extract turmeric, wheat bran, and taro peel. The efficiency of three different concentrations of each solvent was assessed for their antifungal and anti-mycotoxin production against Aspergillus flavus. The results indicated that 75% ethanolic and 25% methanolic extracts of taro peels and turmeric were active against fungus growth, which showed the smallest fungal dry weight ratios of 1.61 and 2.82, respectively. Furthermore, the 25% ethanolic extract of turmeric showed the best result (90.78%) in inhibiting aflatoxin B1 production. After 30 days of grain storage, aflatoxin B1 (AFB1) production was effectively inhibited, and the average inhibition ratio ranged between 4.46% and 69.01%. Simultaneously, the Topsin fungicide resulted in an inhibition ratio of 143.92%. Taro extract (25% acetone) produced the highest total phenolic content (61.28 mg GAE/g dry extract wt.) and showed an antioxidant capacity of 7.45 μg/mL, followed by turmeric 25% ethanol (49.82 mg GAE/g), which revealed the highest antioxidant capacity (74.16 μg/mL). RT-qPCR analysis indicated that the expression of aflD, aflP, and aflQ (structural genes) and aflR and aflS (regulatory genes) was down-regulated significantly compared to both untreated and Topsin-treated maize grains. Finally, the results showed that all three plant extracts could be used as promising source materials for potential products to control aflatoxin formation, thus creating a safer method for grain storage in the environment than the currently used protective method. [ABSTRACT FROM AUTHOR]

Three different concentrations of four (ethanol, acetone, methanol, and diethyl ether) extracts of licorice, doum, and banana peel were evaluated for antifungal and antimycotoxigenic efficiency against a maize aflatoxigenic fungus, Aspergillus flavus. Among them, the licorice diethyl ether 75% extract was intensely active, showing the best wet and dry weight inhibition and exhibiting the highest efficacy ratio (91%). Regarding aflatoxin B1 (AFB1) production, all the plant extracts tested were effective against AFB1 production after one month of maize storage, with average efficacy ratios ranging from 74.1% to 97.5%. At the same time, Thiram fungicide exhibited an efficacy ratio of 20.14%. The relative expression levels of three structural genes (aflD, aflP, and aflQ) and two regulatory genes (aflR and aflS) were significantly downregulated when compared to untreated maize grains or Thiram-treated maize grains. The doum diethyl ether 75% peel extract showed the highest total phenolic content (60.48 mg GAE/g dry extract wt.) and antioxidant activity (84.71 μg/mL). GC–MS analysis revealed that dimethoxycinnamic acid, aspartic acid, valproic acid, and linoleic acid might imbue the extracts with antioxidant capacities in relation to fungal growth and aflatoxin biosynthesis. Finally, the results suggest that the three plant extracts can be considered a promising source for developing potentially effective and environmentally safer alternative ways to control aflatoxin formation, thus creating a potentially protective method for grain storage. [ABSTRACT FROM AUTHOR]