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ID 116754
Author
Kawasaka, Kaito Tokushima University
Keywords
Synergistic antifungal activity
Fungicidal action
Phenolic acid
Violet 405-nm light
Oxidative stress
Growth delay
Content Type
Journal Article
Description
The aim of this study is to investigate the fungicidal spectrum of six phenolic-cinnamic and -benzoic acid derivatives using four fungi, Aspergillus niger, Cladosporium cladosporioides, Trichophyton mentagrophytes and Candida albicans, in a photocombination system with violet 405-nm light. This is the first study to examine the fungicidal mechanism involving oxidative damage using the conidium of A. niger, as well as an assessment of cellular function and chemical characteristics. The results of the screening assay indicated that ferulic acid (FA) and vanillic acid (VA), which possess 4-hydroxyl and 3-methoxy groups in their phenolic acid structures, produced synergistic activity with 405-nm light irradiation. FA and VA (5.0 mM) significantly decreased the viability of A. niger by 2.4 to 2.6-logs under 90-min irradiation. The synergistic effects were attenuated by the addition of the radical scavenger dimethyl sulfoxide. Generation of reactive oxygen species (ROS), such as hydrogen peroxide and hydroxyl radicals, were confirmed in the phenolic acid solutions tested after irradiation with colorimetric and electron spin resonance analyses. Adsorption of FA and VA to conidia was greater than other tested phenolic acids, and produced 1.55- and 1.85-fold elevation of intracellular ROS levels, as determined using an oxidant-sensitive probe with flow cytometry analysis. However, cell wall or membrane damage was not the main mechanism by which the combination-induced fungal death was mediated. Intracellular ATP was drastically diminished (5% of control levels) following combined treatment with FA and light exposure, even under a condition that produced negligible decreases in viability, thereby resulting in pronounced growth delay. These results suggest that the first stage in the photofungicidal mechanism is oxidative damage to mitochondria or the cellular catabolism system associated with ATP synthesis, which is a result of the photoreaction of phenolic acids adsorbed and internalized by conidia. This photo-technology in combination with food-grade phenolic acids can aid in developing alternative approaches for disinfection of pathogenic and spoilage fungi in the fields of agriculture, food processing and medical care.
Journal Title
Journal of Photochemistry and Photobiology B: Biology
ISSN
10111344
NCID
AA10686173
AA11533983
Publisher
Elsevier
Volume
229
Start Page
112411
Published Date
2022-02-18
Remark
著者英表記誤記あり (誤)Koichro Tsuchiya→(正)Koichiro Tsuchiya
Rights
© 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Author
departments
Bioscience and Bioindustry
Pharmaceutical Sciences