Antifungal and Antiaflatoxigenic Methylenedioxy-Containing Compounds and Piperine-Like Synthetic Compounds

Abstract

Twelve methylenedioxy-containing compounds including piperine and 10 piperine-like synthetic compounds were assessed to determine their antifungal and antiaflatoxigenic activities against Aspergillus flavus ATCC 22546 in terms of their structure–activity relationships. Piperonal and 1,3-benzodioxole had inhibitory effects against A. flavus mycelial growth and aflatoxin B1 production up to a concentration of 1000 μg/mL. Ten piperine-like synthetic compounds were synthesized that differed in terms of the carbon length in the hydrocarbon backbone and the presence of the methylenedioxy moiety. In particular, 1-(2-methylpiperidin-1-yl)-3-phenylprop-2-en-1-one had potent antifungal and antiaflatoxigenic effects against A. flavus up to a concentration of 1 μg/mL. This synthetic compound was remarkable because the positive control thiabendazole had no inhibitory effect at this concentration. Reverse transcription-PCR analysis showed that five genes involved in aflatoxin biosynthesis pathways were down-regulated in A. flavus, i.e., aflD, aflK, aflQ, aflR, and aflS; therefore, the synthetic compound inhibited aflatoxin production by down-regulating these genes.

Piperine inhibits aflatoxin B1 production in Aspergillus flavus by modulating fungal oxidative stress response

“…(1-(2-methylpiperidin-1-yl)-3-phenylprop-2-en-1-one) also revealed an inhibition of aflS gene expression while production of AFB1 was no longer detected (Moon et al 2016). During piperine exposure, aflT was not modulated which is in agreement with the fact that this gene is not regulated neither by aflR nor by its co-activator aflS but by other external regulators .…”

Aflatoxin Biosynthesis and Genetic Regulation: A Review

“…These strategies range from good agricultural practices to the use of biocontrol agents or natural compounds able to block toxin production [10]. Even if the exact mechanism of action has not yet been completely elucidated, a few studies already demonstrated that some of these natural products can inhibit AFB1 production by a transcriptional down-regulation of the genes involved in AFB1 synthesis [11][12][13][14][15][16][17][18]. Aflatoxins are the product of a complex biosynthesis pathway involving at least 27 enzymatic reactions [19][20][21][22][23][24].…”

Antifungal and Antiaflatoxigenic Activities of 1,8-Cineole and t-Cinnamaldehyde on Aspergillus flavus

“…Additionally, effective control strategies for fungal infection and toxin production should be organized for the right place and time [19]. Chemical treatment has been seriously considered as an effective method to reduce fungal infection and toxin production in agricultural foods and feedstuffs [9,15,20].…”

“…Measurement of the antifungal activities of the two test compounds were conducted according to a previous report [15]. Briefly, spores, equivalent to 10 6 of A. flavus, were transferred into PDB liquid culture media (25 mL), and the test compounds were added to the liquid media.…”

“…The primers for the genes involved in aflatoxin biosynthesis (yap, aflC, aflD, aflE, aflG, aflK, aflL, erg28, aflR, aflS, and 18S rRNA) are listed in Table S1. The PCR conditions were exactly the same as those reported previously [15].…”