Biological screening of terrestrial and freshwater cyanobacteria for antimicrobial activity, brine shrimp lethality, and cytotoxicity

A total of 44 lipophilic and hydrophilic extracts obtained from 22 samples of cultured terrestrial and freshwater cyanobacteria were investigated for their biological activities. Of these, 54.5% of all extracts showed activity against Grampositive bacteria while 9.1% possessed antifungal activity against Candida albicans. No extract was active against Gram-negative bacteria. Two extracts exhibited significant activity against brine shrimp (Artemia salina). Cytotoxic activity against KB cells was demonstrated for 38.6% of the extracts. Of the 22 cyanobacteria investigated, 19 were active in at least one of the assays used. These results prove that terrestrial and freshwater cyanobacteria are still a promising source of new bioactive natural products.