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Prospecting Microbial Strains for Bioremediation and Probiotics Development for Metaorganism Research and Preservation
Published on: October 31, 2019
Two New Sulfate-Modified Dibenzopyrones With Anti-foodborne Bacteria Activity From Sponge-Derived Fungus Alternaria
Yaping Chen1, Chuanna Liu1, Kaliaperumal Kumaravel2
1College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, China.
Abstract:
At present, foodborne diseases (FBDs) caused by bacteria are gradually increasing every year, and the development of new antibiotics is an urgent necessity for human beings. To find novel antibacterial compounds, three sponge-derived fungal strains (SCSIOS02F40, F46, and F49) were investigated. As a result, Alternaria sp. SCSIOS02F49 was selected for investigation on its secondary metabolites because its ethyl acetate (EtOAc) extract of potato dextrose broth (PDB) culture showed rich metabolites and strong antibacterial activity. Two new dibenzopyrones with rare sulfate group (1-2), together with 10 known compounds (3-12), were isolated from the Alternaria sp. SCSIOS02F49. Their structures were confirmed by nuclear magnetic resonance (NMR), mass spectrometry (MS) data, and comparison with data from the relevant literature. Almost all compounds showed moderate inhibitory activity against eight foodborne bacteria (FBB) with minimum inhibitory concentration (MIC) values in the range of 15.6-250 μg/ml, and minimum bactericidal concentration (MBC) values in the range of 31.3-250 μg/ml. The antibacterial mechanism of compound 1 was preliminarily investigated using growth curves, scanning electron microscopy (SEM), and flow cytometry (FCM), which revealed that compound 1 altered the external structure of Staphylococcus aureus and caused the rupture or deformation of the cell membranes. This research provides lead compounds for the development of new antibiotics or microbial preservatives.
Insights
Novel antibacterial compounds were isolated from a marine fungus, Alternaria sp. SCSIOS02F49, offering potential new treatments for increasing foodborne bacterial diseases and aiding antibiotic development.
Area of Science:
- Marine Natural Products Chemistry
- Antimicrobial Drug Discovery
- Food Microbiology
Background:
- Rising incidence of foodborne diseases (FBDs) necessitates new antibiotic development.
- Marine microorganisms, like fungi, are a promising source of novel bioactive compounds.
- Sponge-derived fungi represent an underexplored resource for discovering antibacterial agents.
Purpose of the Study:
- To isolate and characterize secondary metabolites from the sponge-derived fungus Alternaria sp. SCSIOS02F49.
- To evaluate the antibacterial activity of these compounds against foodborne bacteria.
- To investigate the preliminary antibacterial mechanism of a lead compound.
Main Methods:
- Cultivation of fungal strain SCSIOS02F49 in potato dextrose broth (PDB).
- Extraction with ethyl acetate (EtOAc) followed by chromatographic isolation techniques.
- Structure elucidation using Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS).
- Antibacterial activity assessment via Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays.
- Mechanism of action studies including growth curves, Scanning Electron Microscopy (SEM), and Flow Cytometry (FCM).
Main Results:
- Isolation of two new dibenzopyrones (compounds 1-2) and ten known compounds (3-12).
- Compounds exhibited moderate antibacterial activity against eight foodborne bacteria (MIC: 15.6-250 μg/ml; MBC: 31.3-250 μg/ml).
- Compound 1 demonstrated membrane-damaging effects on Staphylococcus aureus, causing structural alterations and rupture.
Conclusions:
- Alternaria sp. SCSIOS02F49 produces novel dibenzopyrones with significant antibacterial potential.
- These compounds serve as valuable lead structures for developing new antibiotics or food preservatives.
- The study highlights marine-derived fungi as a crucial source for combating antimicrobial resistance.
