In Vitro Antibacterial Activity of Phlorotannins from Edible Brown Algae, Eisenia bicyclis Against Streptomycin-Resistant Listeria monocytogenes

Abstract

(LM) is an important food borne pathogen responsible for listeriosis. Further, LM is an etiological agent associated with life threatening conditions like meningitis and encephalitis. Biofilm forming and drug resistant LM may potentially become difficult to treat infections and hence effective controlling measures are required to prevent LM infections. In view of this, the present study evaluated an anti-listerial potential of edible brown seaweed, , by disc diffusion and micro-dilution methods. The results of the present study suggested that the anti-listerial activity of various phlorotannins isolated form were in the range of 16-256 µg/ml. Among the phlorotannins isolated, fucofuroeckol-A (FAA) exhibited the highest anti-listerial potential (MIC range 16-32 µg/ml) against LM strains tested. Further, in checker board synergy assays, FFA-streptomycin combination exhibited significant synergy (fractional inhibitory concentration index, ∑FIC < 0.5) against aminoglycoside resistant clinical strains of LM. The results of the present study suggested the potential use of edible seaweed as a source of natural phlorotannins to control food borne pathogenic infections.

In vitro evaluation of antimicrobial and antioxidant activities of algal extracts

“…In line with our results, the study conducted by Machu et al (2015) disclosed the highest antioxidant capacity adopting the water extraction for brown algae. Machu et al (2015) tested Eisenia bicyclis that is a brown alga rich in phlorotannins that revealed also antimicrobial capacities against streptomycin resistant Listeria monocitogenes (Kim et al 2018).…”

Pressurized Liquid Extraction (PLE) as an Innovative Green Technology for the Effective Enrichment of Galician Algae Extracts with High Quality Fatty Acids and Antimicrobial and Antioxidant Properties

“…F. vesiculosus produced the best inhibition, IC 50 was 2.24 mg/mL ( E. coli ) and 1.27 mg/mL ( S. aureus ). Despite preliminary results showed that different species of algae have an antimicrobial potential especially against E. coli and S. aureus [ 33 , 34 , 35 ], there are no many studies about the antibacterial activity of seaweeds used in the present study. El-Amraoui and co-workers evaluated the antimicrobial activity of several macroalgae extracts from the Maroccan Atlantic Coast [ 36 ].…”

Algae Polyphenolic Compounds and Modern Antibacterial Strategies: Current Achievements and Immediate Prospects

“…The authors recommended these extracts as an antibacterial preparation against S. aureus , a common causative agent of foodborne toxicoinfections that are accompanied by vomiting, diarrhea, and intestinal spasms [ 122 ]. This bacterium also causes spoilage of meat, including poultry, dairy products, salads, shrimp, and ham [ 123 ]. The extracts have not only antibacterial but also antioxidant effects, suggesting their use as an effective food preservative in an appropriate combination.…”

“…H.J. Kim et al [ 123 ] established the anti-listerial effect of phlorotannins isolated from the alga E. bicyclis . Extraction and purification of compounds are carried out, as described.…”

“…The average value is from 0.32 to 0.37, i.e., there is a pronounced synergistic effect. The authors suggested that marine algae could be a source of new effective and low-toxic natural compounds for controlling the spread of L. monocytogenes in foods and in the human organism [ 123 ].…”