Abstract
Objective: The main aim of this research work was to evaluate the antibacterial and haemolytic activities of different extracts of Euglena viridis (E. viridis), a freshwater microalga.Methods: The solvent extraction has been followed by a preliminary screening of phytochemicals. The ethanolic extract, Eu(EtOH) was chromatographed on a silica gel column. The column was eluted with hexane and then with ethyl acetate/hexane mixtures of increasing polarity, 16 fractions (Ef1-Ef16) were collected and grouped according to their TLC (Thin layer chromatography). Antibacterial activities of different fractions of E. viridis against Pseudomonas putida (P. putida) ATCC49828, P. aeruginosa MTCC 35672, Aeromonas hydrophila (A. hydrophila) MTCC 646, ATCC 49140, eleven strains of Staphylococcus aureus (S. aureus) and thirteen strains of Flavobacterium columnare (F. columnare) was done using disc diffusion methods. Haemolytic activity was carried out by using blood agar plate method. The MIC (Minimum inhibitory concentration) values of active fractions were determined by the broth dilution method.Results: The results showed that the Eu(EtOH) poses significantly (p≤0.5) higher zone of inhibition (14.0±0.28, 13.5±0.28 mm) against FLV8 and FLV9 respectively. Three strains of Flavobacterium (FLV5, FLV6 and FLV10) were highly sensitive (zone size, 17 mm, 17.5 mm) towards 30% EA: Hex chromatographic eluents (Ef11) with lowest MIC values, e. i 60 µg and 30 µg respectively. Two chromatographic fractions, Ef11 and Ef13 were highly effective (zone size, 14.5 mm and 13.5 mm) against S. aureus (SA5) with lowest MIC value (60µg). Haemolytic activities of all the algal extracts were noticed that both Eu(EtOH) and methanolic extract, Eu(MeOH) of Euglena gives negative results.Conclusion: These findings suggest that the extract obtained from E. viridis have active substances contributing to the increasing antibacterial potential.
Highlights
Antibiotics are naturally occurring or synthetic organic compounds which inhibit or destroy selective bacteria, generally at low concentrations [1]
Some researchers have envisioned the enormous possibilities of algae and microalgae as potential source of bioactive compounds; some microalgae have been studied as a potential natural source of different functional compounds [3]
An alternative to the inhibition of bacterial growth would lie in an approach to prevent pathogens from establishing a successful infection that can be done through developing new antipathogenic drugs
Summary
Antibiotics are naturally occurring or synthetic organic compounds which inhibit or destroy selective bacteria, generally at low concentrations [1]. The success of antibiotics against diseasecausing microbes is among modern medicines’ great achievements. This kind of drug is beginning to lose its usefulness due to the development of resistance on the part of microbes. In the face of this scenario, the search for substances from natural sources, including algae, has been gaining importance in the pharmaceutical companies. Much attention has been focused on the microalgae as sources of the novel, biologically active compounds such as phycobiline, phenols, terpenoids, steroids and polysaccharide [4]. Freshwater algae are a rich source of structurally novel and biologically active metabolites. Many chemically unique compounds with various biological activities have been isolated and some of them are under investigation and are being used to develop new pharmaceuticals
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
