Licorice, Doum, and Banana Peel Extracts Inhibit Aspergillus flavus Growth and Suppress Metabolic Pathway of Aflatoxin B1 Production

Abstract

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.

The Application of Pomegranate, Sugar Apple, and Eggplant Peel Extracts Suppresses Aspergillus flavus Growth and Aflatoxin B1 Biosynthesis Pathway

“…They reported similar reductions in Aspergillus fungal dry weight after using essential oils. Doum, banana, and licorice peel extracts exhibited similar decreases [15]. The findings were similarly consistent with those of Yazdani et al [68] and Oliveira and Furlong [29].…”

“…Generally, the aflR and aflS are essential regulatory genes for AFB1 synthesis. Many reports assed significant correlations between the transcriptional levels of the two regulatory genes and AFB1 production [15,80]. The results showed the downregulation of two genes, aflR, and aflS, for all treatments compared to infected (untreated) controls.…”

“…The fungicide treatment (2.5 mg/mL) was treated with Topsin (Thiophanate methyl, 70% wettable powder, United Phosphorus, Inc., King of Prussia, PA, USA), which was used as a control. Subsequently, each bottle was inoculated with a 5 mm disc of the aflatoxigenic fungus and kept for 30 days at 30 • C. The shape and odor of the maize grains were assessed after the storage period, using the scale developed by Youssef et al [15]. All of the analyzed grains were crushed and refrigerated at 4 • C until they were used for further aflatoxin studies.…”

“…Currently, the use of plant-based natural antifungal agents is considered a beneficial and healthy practice in this regard [13,14]. Plant extracts could be employed as antimicrobial agents or for improved food storage and preservation due to their high activity, the simplicity of their production and utilization, their reliability, and their biocompatibility [15,16].…”

Mycotoxins in milk: Occurrence and evaluation of certain detoxification attempts

“…This variation in mycotoxin behavior as a response to different shaking speeds could be associated with the differences in their molecule's chemical and physical properties and molecular weights (Omar, 2016). This notice matched those of (Youssef, 2019a) et al, 2015) and (Youssef, Qari, Behiry, et al, 2021;Youssef, Qari, Matar, et al, 2021) showed mycotoxins like aflatoxin and Zear can be significantly inhibited by plant derivatives such DOU, GTL, banana peels, and LIC.…”