This study was conducted to evaluate the total phenolic, flavonoid content, antioxidant, and antibacterial activity of hydomethanolic Limnospira fusiformis TL03 .

The total phenolics and flavonoids were determined by using the Folin-Ciocalteu and aluminum chloride methods, respectively. The YL 9100 HPLC was used to identify the phenolic compounds. 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and beta-carotene-linoleic acid tests were used to evaluate antioxidant activity in vitro. The antimicrobial activities were tested against six bacteria using the disc diffusion method and the agar dilution method.

The total phenolic and flavonoids contained in the hydromethanolic extract were 18.41 ±0.18 mg GAE/g DW and 2.11 ±0.12 mg quercetin/g DW, respectively. The polyphenol analysis showed the presence of: Ascorbic acid, Gallic acid, Luteotin , Quercetine, Kaempferol.

This extract shows strong DPPH radical scavenging and β-carotene bleaching activities with a percentage of 86.19±1.61% and 85.87±1.65%, respectively, in addition to activity antibacterial, in which the zone inhibition diameters (ZID) range from 33.33±1.53 to 11±1 mm, with the higher value antibacterial activity (33.33±1.53 mm) registered against S. aureus and the lower minimum inhibitory concentrations (MIC) observed against K pneumonia.