Evaluation of cytotoxicity, analysis of metals and cumulative risk assessment in microalgae

Abstract

Microalgae are one promising source for the production of bioactive compounds. However, microalgae can accumulate harmful substances. So, our objectives were (i) to evaluate cell viability after Phaeodactylum triconutum (0% and 65% cell disruption, DR) and Tetraselmis chuii (0% and 67% DR) freeze-dried exposure in HepG2 cells by MTT assay; (ii) to evaluate cell viability after P. triconutum and T. chuii extract exposure; (iii) to assess the effect in cell viability when they were simultaneously exposed to T-2 toxin and, (iv) to evaluate if inflammatory response is related to the mechanism of toxicity of these microalgae by qPCR assays. Results demonstrated that cell viability did not increase after freeze-dried microalgae exposure in HepG2 cells. And, no IC₅₀ values were observed. However, an increase in HepG2 cell viability after exposure of T. chuii 0% DR extract at 5, 25 and 100 µg/mL was observed. Additionally, 1:64 diluted T. chuii 0% DR with IC₅₀/4 T-2 and with IC₅₀/2 T-2 and 1:32 diluted T. chuii 0% DR with IC₅₀/4 T-2 showed an increase in cell viability. Both microalgae increased the relative TNF-α, IL-1β and IL-6 mRNA expression. Concluding, no cytotoxic effect was evidenced but, it was noted up-regulation of inflammatory genes after T. chuii exposure in HepG2 cell. Thus, more studies related the mechanistic toxicity of microalgae are needed to evaluate the potential toxicological risk of inflammation of these novel foods. .

Keywords:

• microalgae
• T-2 toxin
• HepG2 cells
• cytotoxicity
• inflammation

Additional information

Funding

This research was funded by the Spanish Ministry of Science and Innovation Project (PID2020-115871RB-I00). M. Taroncher thanks the FPI grant (PRE2021-096941) provided by Spanish Ministry of Science and Innovation Project. The authors are thankful to Katerina Kousoulaki (NOFIMA, Norway), Marielena Kokkali (NOFIMA, Norway), Dorinde Kleingris and her team at the National Algae pilot plant in Mongstad (NAM) in Norway for cultivating and providing the microalgal biomass samples to carry out the experiments. Finally, the authors also acknowledge the Research Council of Norway, which provided funding through the A2F (Algae 2 Future) project (Project No. 267872/E50) for the production of the microalgae biomass used in this study.