Cinnamaldehyde, a Promising Natural Preservative Against Aspergillus flavus.

Su Qu,Yongxin Li,Kunlong Yang,Jun Tian,Yongguo Liu,Xiaona He,Man Liu,Qingru Geng,Lei Chen

doi:10.3389/fmicb.2019.02895

Abstract

The problem of food spoilage due to Aspergillus flavus (A. flavus) needs to be resolved. In this study, we found that the minimum inhibitory concentration of cinnamaldehyde (CA) that inhibited A. flavus was 0.065 mg/ml and that corn can be prevented from spoiling at a concentration of 0.13 mg/cm3. In addition to inhibiting spore germination, mycelial growth, and biomass production, CA can also reduce ergosterol synthesis and can cause cytomembrane damage. Our intention was to elucidate the antifungal mechanism of CA. Flow cytometry, fluorescence microscopy, and western blot were used to reveal that different concentrations of CA can cause a series of apoptotic events in A. flavus, including elevated Ca2+ and reactive oxygen species, decrease in mitochondrial membrane potential (Δψm), the release of cytochrome c, the activation of metacaspase, phosphatidylserine (PS) externalization, and DNA damage. Moreover, CA significantly increased the expression levels of apoptosis-related genes (Mst3, Stm1, AMID, Yca1, DAP3, and HtrA2). In summary, our results indicate that CA is a promising antifungal agent for use in food preservation.

Highlights

Aspergillus flavus (A. flavus) is one of the most common species among the filamentous fungi
We found that the minimum inhibitory concentration of cinnamaldehyde (CA) that inhibited A. flavus was 0.065 mg/ml and that corn can be prevented from spoiling at a concentration of 0.13 mg/cm3
We found that A. flavus treated with CA showed minimum inhibitory concentration (MIC) at 0.065 mg/ml when the viability of the CA treatment was assessed after 5 days according to visual observation (Figure 1A)

Summary

Introduction

Aspergillus flavus (A. flavus) is one of the most common species among the filamentous fungi. The notorious A. flavus metabolite aflatoxin B1, which has been recognized by the World Health Organization (WHO) as a primary carcinogen, is absorbed by humans and animals through contaminated agricultural crops and animal feed, such as maize, peanuts, nuts, cottonseed, and edible oil (Yang et al, 2015). Research into new antifungal agents needs to be carried out urgently because of the drug resistance and the toxicity of the compounds currently available (Sarkar et al, 2014; Qu et al, 2019). The Mechanism of A. flavus Inhibition by Cinnamaldehyde increasing numbers of scientists are exploring novel natural products from medicinal plants such as Geraniol and Citral in an attempt to solve the question of fungal drug resistance and with consideration for the natural low toxicity and high antifungal activity of these products (Atanasov et al, 2015; Tang et al, 2018)

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