In vitro toxicity of microalgal and cyanobacterial strains of interest as food source

The general objective of the present work was to evaluate the toxicity of 11 microalgal strains and one natural bloom, selected as potential food or food ingredients due to their nutritional quality, in two models, human dermal fibroblasts and Artemia salina. Methanolic and aqueous extracts of the biomasses were tested on A. salina for 24 and 48 h at concentrations up to 12.5 g L-1 of extracted biomass. Only aqueous extracts were tested on fibroblasts for 24 h. Chlorella vulgaris Roquette, C. vulgaris Allma, Tetraselmis suecica F&M-M33, and Porphyridium purpureum F&M-M46 showed no toxicity towards A. salina and fibroblasts. Only Klamath powder was toxic to both models with all types of extracts. Tisochrysis lutea (T-ISO) F&M-M36, Chlorella sorokiniana F&M-M49 grown in BG11, and C. sorokinina IAM C-212 showed toxicity, even if to different extents, to fibroblasts and, only with the methanolic extract, to A. salina. The remaining strains showed no toxicity towards A. salina, but were toxic to fibroblasts: Arthrospira platensis F&M-C256 and Nannochloropsis oceanica F&M-M24 exhibited low toxicity, Nostoc sphaeroides F&M-C117 medium toxicity and Phaeodactylum tricornutum F&M-M40 high toxicity. Although in some cases the two models provided contrasting results, this work confirms their validity for preliminary screening of toxicity. The models are able to indicate organisms and substrates of potential toxicity and may well serve as guidelines for in vivo tests on mammals, which are necessary to apply for novel food in the EU.