Brown and Red Seaweeds Serve as Potential Efflux Pump Inhibitors for Drug-Resistant Escherichia coli

• Published in: Evidence-based complementary and alternative medicine Vol. 2019; no. 2019; pp. 1 - 12
• Main Authors: Hsu, Pang-Hung, Lin, Hong-Ting Victor, Chiu, Jen-Yu, Lai, Margaret, Lu, Wen-Jung, Lin, Hsuan-Ju
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 2019; Hindawi; Hindawi Limited
• Subjects: Algae; Alkaloids; Antibiotics; Antimicrobial agents; Aromatic compounds; Bacteria; Biological activity; Cell membranes; Chemotherapy; Clarithromycin; Drug resistance; E coli; Escherichia coli; Ethidium bromide; Evidence-based medicine; Experiments; Flavonoids; Indoles; Inhibitors; Membranes; Metabolites; Multidrug resistance; Natural products; Pathogens; Phenolic compounds; Phenols; Porphyra; Regrowth; Seaweeds; Staphylococcus infections; Synergistic effect; Terpenes
• ISSN: 1741-427X; 1741-4288
• DOI: 10.1155/2019/1836982

Multidrug-resistant pathogens are a significant clinical problem. Efflux pump inhibitors (EPIs) can restore the activities of existing antibiotics by interfering with drug efflux pumps located in bacterial cell membranes. Seaweeds are important sources of biologically active metabolites of natural origin; however, their potential as EPIs remains uninvestigated. Here, functional extracts from the brown seaweeds Laminaria japonica and Sargassum horneri and the red seaweeds Gracilaria sp. and Porphyra dentata were evaluated as potential EPIs against drug-resistant Escherichia coli. All these extracts were found to potentiate the activities of drugs in modulation tests, although not to the same extent. Synergistic effects of the extracts and the drug clarithromycin were observed from the onset of Time-kill assays, with no evidence of bacterial regrowth. Ethidium bromide accumulation studies revealed that the efflux decreased in the presence of each extract, as indicated by the presence of EPIs. Most identified EPIs that have been discovered to date have aromatic structures, and the seaweed extracts were found to contain various terpenes, terpenoids, phenolic compounds, indoles, pyrrole derivatives, alkaloids, and halogenated aromatic compounds. Our study highlights the potential of these compounds of the seaweeds as drug EPIs.