Bioactive potential of Cyanobium sp. pigment-rich extracts

Cyanobacteria are able to synthesize high-value compounds, such as pigments, known for their bioactivities and several industrial uses. One of the key points for the extraction of pigments is solvent selection. Solvent interferes on pigments concentration, thus affecting the bioactive potential of the extracts. In this work, using frozen-dried biomass of Cyanobium sp. LEGE 06113, organic and aqueous pigment-rich extracts were obtained by a classic extraction methodology using four solvents — acetone (A), ethyl acetate (EA), ethanol (E) and water (W). In order to increase the efficiency of extraction from the cyanobacterium biomass, successive extractions were performed by using water after organic extraction (A-W, E-W, EA-W) and acetone after the aqueous extraction (W-A). Extraction yield and profile of carotenoids, phycobiliproteins, and phenolic compounds were quantified. The bioactive potential of Cyanobium sp. extracts was assessed in terms of antioxidant capacity (ABTS•+, •NO, O2•− scavenging), anti-inflammatory capacity (COX inhibition), and cytotoxicity (HepG2). W-A showed the higher antioxidant capacity and higher content in carotenoids. E-W showed the highest content in phycobiliproteins and great antioxidant capacity. In terms of anti-inflammatory capacity, 100 μgE mL−1 of E-W extract exhibited capacity to inhibit both COX-1 and COX-2 enzymes. Finally, in what concerns the cytotoxic evaluation, E, W, A-W, E-W, and EA-W revealed to have no cytotoxic effects in concentrations up to 750 μgE mL−1. Overall, this work constitutes a valid contribution for the valorisation of Cyanobium sp. pigment-rich extracts for biotechnological applications.

A PhD fellowship (SFRH/BD/136767/2018) for author F.P. was granted by Fundação para a Ciência e Tecnologia (FCT, Portugal) under the auspices of Programa Operacional Capital Humano (POCH), supported by the European Social Fund and Portuguese funds (MECTES). This work was financially co-supported by the strategical funding from FCT UIDB/04423/2020 and UIDP/04423/2020, European Union Horizon 2020 programme - GenialG - Genetic diversity exploitation for innovative macro-algal biorefinery (ID: 727892) and the Atlantic Interreg Projects Enhance MicroAlgae - high-added value industrial opportunities for microalgae in the Atlantic Area (EAPA_338/2016), and BLUEHUMAN - BLUE biotechnology as a road for innovation on HUMAN’s health aiming smart growth in Atlantic Area (EAPA_151/2016). The authors acknowledge the support and the use of resources of EMBRC-ERIC, specifically of the Portuguese infrastructure node of the European Marine Biological Resource Centre (EMBRC-PT) CIIMAR–PINFRA/22121/2016–ALG-01-0145-FEDER-022121, financed by the European Regional Development Fund (ERDF) through COMPETE2020–Operational Programme for Competitiveness and Internationalisation (POCI) and national funds through FCT/MCTES.