Antialgal, antibacterial and antifungal activity of two metabolites produced and excreted by cyanobacteria during growth

Abstract

The antimicrobial activity of two cyanobacterial exometabolites, norharmane (9H-pyrido(3,4-b)indole) and 4,4'-dihydroxybiphenyl, was determined in suspension assays. Good anticyanobacterial activities (concentrations of 8-80 microg ml(-1)) and moderate antibacterial (16-160 microg ml(-1)) and antifungal (32-40 microg ml(-1)) activities were found for both compounds. The natural function as allelopathic chemicals and a possible applicability as antifouling agents or leads for the development of new antifouling chemicals are discussed.

Cyanobacteria, Lyngbya aestuarii and Aphanothece bullosa as antifungal and antileishmanial drug resources

“…However, antifungal activity is also reported with crude extract and pure compounds from other freshwater cyanobacteria such as Anabaena, Nostoc, Aphanocapsa, Synechocystis, Synechococcus, Oscillatoria, Nodularia, Calothrix [20,21,[36][37][38][39] , while marine cyanobacteria are little explored with regard to antifungal activity except various species of as Leishmania confervoides, Leishmania majuscula [12,13] . This activity was caused due to species specific biomolecules as specific secondary metabolite produces in specific organism and in specific habitat [5][6][7] .…”

“…Fresh water Aphanothece pallida and Aphanothece stagnina were found to possess antifungal activity [20] . Although many fresh water cyanobacteria were screened for antialgal, antibacterial as well as antifungal activity such as Nodularia harveyana for Norharmane (9H-pyrido-3,4-b-indole), Nostoc insulare for 4,4'-dihydroxy biphenyl [21] , Fischerella musciola for herbicidal and antifungal, Fischerellin A and Synechocystis for partially purified AK3 as antifungal [22,23] . In the present investigation we have selected two cyanobacterium from different habitats, Leishmania aestuarii (L. aestuarii) from brackish water in Chilka Lake, Orissa and Aphanothece bullosa (A. bullosa) from paddy field around Banaras Hindu University (fresh water) for their antifungal and antileishmanial activities.…”

Characterization of the Biocidal Spectrum of Extracellular Filtrates of Microcystis aeruginosa

“…4) in the inhibition of the fungus. The presence of anti-fungal compounds has been reported in a few cyanobacterial genera [6,7,28,29].…”

“…The culture filtrate of the cyanobacterium Microcystis aeruginosa isolated from Laxmikund pond, Varanasi, showed algicidal activity [7]. Preliminary chemical characterization of the extract (in different solvent systems) was carried out through TLC.…”

“…Ecologically, these antimicrobial compounds of cyanobacteria are important as they may play a critical role in the allelopathic interactions among microorganisms in any ecological community/niche. Only recently the chemical, pharmaceutical, immuno-modulatory, bio-regulatory and therapeutic potential of these exciting bio-molecules have been recognized internationally [6,7]. Scientists all over the world are now looking for the commercial exploitation of these bioactive molecules with novel chemical and molecular structures [8].…”