Separation and characterization of antioxidants from Spirulina platensis microalgacombining pressurized liquid extraction, TLC and HPLC-DAD

A new procedure has been developed to separate and characterize antioxidant compounds from Spirulina platensis microalga based on the combination of pressurized liquid extraction (PLE) and different chromatographic procedures, such as Thin-Layer Chromatography (TLC), at preparative scale, and High Performance Liquid Chromatography (HPLC) with a Diode Array Detector (DAD). Different solvents were tested for PLE extraction of antioxidants from Spirulina platensis microalga. An optimized pressurized liquid extraction process using ethanol (generally recognized as safe, GRAS) as extraction solvent has been obtained that provides natural extracts with high yields and good antioxidant properties. TLC analysis of this ethanolic extract obtained at 115°C for 15 min was carried out and the silica layer was stained with a DPPH• (diphenyl-pycril-hydrazyl) radical solution to determine the antioxidant activity of the different chromatographic bands. Next, these coloured bands were collected for their subsequent analysis by HPLC-DAD revealing that the compounds with the most important antioxidant activity present in Spirulina extracts were carotenoids, as well as phenolic compounds and degradation products of chlorophylls.JAM and MH thank MCYT for FPI grants. Authors thank MCYT (project AGL2002-04621- C02-02) for financial support.Peer reviewe