Nostoc piscinale Gt-319, a New Cyanobacterial Strain with Cytotoxic Activity

A total of 100 supernatant and methanol extract samples obtamed from three weeks' incubation or 50 different isolate strains of cyanobacteria with paddy-fields origin were investigated for their cytotoxicity properties. Fifteen supernatants and 10 methanol extract samples exhibited cytotoxic activity against Balb-C cells while one methanol extract sample possessed a cytotoxic effect against five different cell lines including HeLa, Vero, Caco-2, HepG-2 and CHO more than vincristine, 5-fluorouracil and methotrexate when used at their IC sub(50) concentrations. The later potent extract was achieved from the cyanobacterium strain GT-319. It was characterized as Nostoc piscinale Kuetzing ex Bornet and Flahault 1888 according to the morphological studies. Identification of the species was performed following molecular taxonomy by 16S rRNA sequencing. This is the first report on the cytotoxic activity of N. piscinale GT-319.