Exploitation of filamentous and picoplanktonic cyanobacteria for cosmetic applications: potential to improve skin structure and preserve dermal matrix components

The use of natural products in skin care formulations gained interest as a concern for modern societies. The undesirable side effects of synthetic compounds, as well as the associated environmental hazards, have driven investigation on photosynthetic organisms as sustainable sources of effective and environmentally friendly ingredients. The use of natural extracts in cosmetics has been highlighted and, along with plants and algae, cyanobacteria have come into focus. Due to their low culture demands, high grow rates and ability to produce a wide variability of bioactive metabolites, cyanobacteria emerged as an economic and sustainable base for the cosmetic industry. In this study, we evaluated the potential of ethanol extracts of picocyanobacteria strains of the genera Cyanobium and Synechocystis and filamentous strains of the genera Nodosilinea, Phormidium and Tychonema for skin applications, with focus in the field of anti-aging. The extracts were analyzed for their pigment profile, phenolic content, antioxidant potential, cytotoxicity against keratinocytes (HaCat), fibroblasts (3T3L1), endothelial cells (hCMEC/D3) and capacity to inhibit hyaluronidase (HAase). The total carotenoid content ranged from 118.69 to 383.89 μg g−1 of dry biomass, and the total phenolic content from 1.07 to 2.45 mg GAE g−1. Identified carotenoids consisted of zeaxanthin, lutein, canthaxanthin, echinenone and β-carotene, with zeaxanthin and lutein being the most representative (49.82 and 79.08 μg g−1, respectively). The highest antioxidant potential was found for Phormidium sp. LEGE 05292 and Tychonema sp. LEGE 07196 for superoxide anion radical (O2•−) scavenging (IC50 of 822.70 and 924 μg mL−1, respectively). Low or no cytotoxicity were registered. Regarding HAase inhibition, Tychonema sp. LEGE 07196 and Cyanobium sp. LEGE 07175 showed the best IC50 (182.74 and 208.36 μg mL−1, respectively). In addition, an increase in fibroblast proliferation was registered with these same strains. From this work, the ethanol extracts of the species Tychonema sp. and Cyanobium sp. are particularly interesting for their potential application in anti-aging formulations, once they stimulated fibroblast proliferation and inhibit hyaluronic acid digestion.

This work was done in the framework of the projects: BLUEHUMAN-BLUE biotechnology as a road for innovation on HUMAN’s health aiming smart growth in Atlantic Area-EAPA_151/2016 of the Interreg Atlantic Area Programme funded by the European Regional Development Fund; EnhanceMicroAlgae - High added-value industrial opportunities for microalgae in the Atlantic Area (EAPA_338/2016) of the Interreg Atlantic Area Programme funded by the European Regional Development Fund; ALGAVALOR - MicroALGAs: integrated production and valorization of biomass and its various applications - SI I&DT no. 352234-supported by the PORTUGAL 2020 through the European Regional Development Fund; and supported by the FCT Projects UIDB/04423/2020 and UIDP/04423/2020. 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.