Marine macroalgae as a promising source of natural product

From the ancient time, marine macroalgae have proven to be a promising source of natural products with various pharmacological and biological activities, including antiviral, anticoagulant, anti-tumoral, antimetastatic, and anti-inflammatory effects (Leandro et al. 2019, Wang et al. 2020). Today more than ever, macroalgae are a precious resource for the extraction of active molecules, and interest on them has increased widely in recent years, also due to the intrinsic eco-sustainability of the algal industry. In our studies, different species of macroalgae were collected from Venice Lagoon, Lake Ganzirri, and the Strait of Messina, in Italy, to investigate the biological activity of sulphated polysaccharides and secondary metabolites. Extracts from Undaria pinnatifida (Ochrophyta) and Asparagopsis taxiformis (Rhodophyta) were tested against Leishmania infantum, the prevalent agent of leishmaniasis in the Mediterranean, showing a remarkable activity and demonstrating the potential of macroalgae as a relevant source of antiprotozoal products (Genovese et al. 2012, 2013, Vitale et al. 2015, Armeli Minicante et al. 2016) Additionally, marine macroalgae were found to produce a wide variety of bioactive metabolites, which exhibit antiviral, hypocholesterolaemic, hypotensive, antibacterial, anticoagulant, anthelmintic, anticancer, cytotoxic, and antifungal activities (Faggio et al. 2015, Rocha et al. 2018, Álvarez-Viñas et al. 2021). In this context, the biological activity of polysaccharides from Chaetomorpha aerea (Chlorophyta), Agardhiella subulata and Hypnea cornuta (Rhodophyta) were evaluated for their effects on the adhesion and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus (Zammuto et al. 2022). Crude extracts showed dose-dependent inhibitory effects on biofilm formation, without exerting any antibacterial activity. In conclusion, macroalgae demostrated their amazing potential as a source of natural products for the development of biomolecules, which may provide novel drugs. Furthermore, when marine macroalgal biomass collected in dystrophic environments are exploited, the added value of transforming a waste into an economic resource is gained (Spagnuolo et al. 2022).