Optimization of extraction process of polyphenols from wild halotolerant cyanobacteria, Phormidium versicolor (NCC 466)

This study focuses on the extraction optimization and characterization of polyphenols from the wild blue-green microalga Phormidium versicolor, as well as in vitro evaluation of antioxidant and antimicrobial activities. The optimal extraction conditions were as follows: extraction temperature at 52 degrees C, extraction time of 30 min, and solid-to-liquid ratio of 1:50 g mL(-1) under ultrasonic-assisted extraction in the ethanol-based solvent. Yield of the polyphenol extract of Phormidium versicolor (P-Pv) increased from 40.35 to 76.74 mg g(-1) dw. Polyphenol compounds of P-Pv were analyzed through high-performance liquid chromatography and Fourier transform infrared (FTIR) spectroscopy. Results revealed the presence of four polyphenol compounds with the highest concentration of kaempferol (31.8 mu g mg(-1)) extract. The FTIR analysis shows the existence of alcohol bond and flavonoids. In vitro antioxidant activity suggested that P. versicolor polyphenol extract had effective scavenging activity of DPPH, ABTS, and nitric oxide radicals. Furthermore, the current extract exhibited effective antimicrobial properties in vitro. Such pharmaceutical activities could prove valuable for potential future applications involving the P. versicolor cyanobacteria.