Antimicrobial therapeutics isolated from algal source: retrospect and prospect

Abstract

In the last few decades, attention on new natural antimicrobial compounds has arisen due to a change in consumer preferences and the increase in the number of resistant microorganisms. Algae are defined as photosynthetic organisms that demonstrate a wide range of adaptability to adverse environmental conditions like temperature extremes, photo-oxidation, high or low salinity, and osmotic stress. Algae are primarily known to produce large amounts of secondary metabolite against various kinds of pathogenic microbes. Among these algae, micro and microalgae of river, lake, and algae of oceanic origin have been reported to have antimicrobial activity against the bacteria and fungi of pathogenic nature. Various polar and non- polar extracts of micro- and macro algae have been used for the suppression of these pathogenic fungi. Apart from these, certain algal derivatives have also been isolated from these having antibacterial and antifungal potential. Among the bioactive molecules of algae, polysaccharides, sulphated polysaccharides, phyco-cyanobilins polyphenols, lectins, proteins lutein, vitamin E, B 12 and K 1 , peptides, polyunsaturated fatty acids and pigments can be highlighted. In the present review, we will discuss the biological activity of these derived compounds as antifungal/ antibacterial agents and their most promising applications. A brief outline is also given for the prospects of these isolated phytochemicals and using algae as therapeutic in the dietary form. We have also tried to answer whether alga-derived metabolites can serve as potential therapeutics for the treatment of SARS-CoV-2 like viral infections too.

Profile of secondary metabolites of Citrus hystrix DC from several solvents and its potential as an antibacterial substance

“…Several other studies reported similar results, extraction using ethanol solvents produced better tannin yields than other solvents [25][26][27] Low amounts of tannins added to bovine feed can improve rumen microbial function and have antioxidant and pathogenic antibacterial effects [22]. Tannin have an anti-microbial effect against several types of bacteria such as of E. coli O157:H7 [28], Bacillus subtilis, Salmonella Enteritica, Clostridium perfringens, and Staphylococcus aureus [26] . Tannins have also been reported to inhibit the growth of methanogenic bacteria [20,29] However, tannins become antinutritional factors at large concentrations, decreasing the ability of nutrients, particularly proteins and carbohydrats, to be digested [30] .…”

Characterization of Pseudomonas sp. NIBR-H-19, an Antimicrobial Secondary Metabolite Producer Isolated from the Gut of Korean Native Sea Roach, Ligia exotica

“…Living organisms produce various types of bioactive secondary metabolites to defend themselves against environmental threats and infection by microbial pathogens [49][50][51][52][53][54]. Bacteria also produce a variety of high-value chemicals, including the unique biological functions of secondary metabolites.…”

A Survey of Recently Discovered Naturally Occurring Organohalogen Compounds

“…The algae emissions of volatile halocarbons and their impact on the environment are reviewed, 18 and the antimicrobial therapeutic potential of algae metabolites is outlined. 19…”