The purpose of this work is to underline the potential of cyanobacteria in the production of health foods and as an antioxidant carrier in the food and pharmaceutical industries. The present study investigates the phenolic profile of extracts of several cyanobacteria (Nostoc sp., Nostoc cf. commune, Nodularia spumigena, Leptolyngbya protospira, Phormidiochaete sp., and Arthrospira platensis) from the culture collection at the Spanish Bank of Algae. The use of reversed-phase high-performance liquid chromatography (RP-HPLC) permited the identification of 6 phenolic constituents: gallic acid, (+) catechin, (-) epicatechin, syringic acid, protocatechuic acid and chlorogenic acid. The extracts were screened for their antioxidant activity in inhibiting the stable radical 1,1-diphenyl-2- picrylhydrazyl (DPPH). Cyanobacteria Nostoc cf. commmune was the only one that showed the presence of phenolic compounds (71 µg of gallic acid and 2.16 µg of protocatechuic acid per gram of freeze-dried biomass). The tested phenolic compounds were not detected in thee extracts derived from Leptolyngbya protospira, Phormidiochaete sp., Nodularia spumigena and Nostoc sp. However, these four cyanobacteria strains showed antioxidant activity.

178

177

2