064 | Sustainable extraction and functional characterization of bioactive compounds from Spirulina platensis for nutraceutical and cosmetic applications

Carmen Sica¹, Chiara Copat¹, Gea Oliveri Conti¹, Sheima Inoubli², Margherita Ferrante¹ | ¹Department of Medical, Surgical Sciences and Advanced Technologies "G.F. Ingrassia", University of Catania, Italy; ²Department of Chemical Engineering, Universidade de Vigo, Campus de Ourense, Spain.

The growing demand for sustainable bioactive compounds in the nutraceutical and cosmetic sectors has highlighted Spirulina platensis as a promising microalgal resource, due to its rich content in phenolic compounds, pigments, fatty acids, and proteins. However, the development of environmentally friendly and efficient extraction methods is essential to fully exploit its functional potential. This study applied integrated green extraction techniques, including microwave-assisted extraction (MAE) at 80°C and 180 °C, using eco-friendly solvents such as p-cymene, D-limonene, 2-methyltetrahydrofuran (2-MeTHF), and distilled water. In parallel, a freeze–thaw protocol using ultrapure water was implemented to extract phycocyanin. Spectrophotometric assays were used to determine total phenolic content (via Folin–Ciocalteu method), pigment concentration, and antioxidant capacity (DPPH, FRAP, TEAC). Fatty acids were analyzed using the UNE-EN ISO 12966-3 method. Biological evaluation was carried out via MTT assays on olfactory ensheathing cells (OECs), previously isolated from P2 mice and cultured under defined conditions. Among all conditions tested, green solvents showed excellent extraction performance. In particular, p-cymene at 80°C yielded the highest extraction of phenolic compounds (69.88%) with strong antioxidant potential (FRAP: 1.25 mmol Fe²⁺/g extract; DPPH inhibition: 82.4%; TEAC: 1.10 mmol Trolox/g). Fatty acid profiling confirmed palmitic acid as the dominant component (38.6%). The freeze–thaw method successfully extracted phycocyanin using only ultrapure water. Lyophilized phycocyanin showed significant antioxidant and cytoprotective effects. In OECs stressed with hydrogen peroxide (H₂O₂), which caused a 40% reduction in viability compared to the control, treatment with lyophilized phycocyanin restored cell viability with an 80% increase, indicating a robust protective effect. This result suggests that the extracted phycocyanin exerts not only antioxidant but also cellular repair-promoting activity under oxidative stress. Furthermore, the MTT assay performed with the p-cymene extract at concentrations of 50, 100, and 200 µg/mL demonstrated strong biocompatibility (>90% viability) and anti-inflammatory potential. Specifically, at 100 µg/mL, the extract restored viability from 62% (LPS-stressed cells) to 88%, confirming a clear inflammation-modulating effect. Although the antioxidant capacity under stress was not quantified through intracellular ROS assays, the observed cellular response strongly supports the extract’s antioxidant efficacy. The optimized use of green solvents not only improved extraction yields and antioxidant activity but also preserved the bioactivity of the extracts in vitro. The Spirulina extract, particularly that obtained with p-cymene, showed excellent biocompatibility and anti-inflammatory potential in OEC cultures. These findings support its application in nutraceutical and cosmeceutical formulations and contribute to the development of sustainable biorefinery processes.