Sustainable Phytosterol Extraction from Codium tomentosum Using Eutectic Solvents

Macroalgae are a promising source of natural compounds like phytosterols, known for their cholesterol-lowering effects and other biological properties. However, they have often been challenging to extract efficiently due to a lack of sustainable extraction techniques. This study aimed to exploit eutectic solvents (ES) in the sustainable extraction of phytosterols. The conductor-like screening model for real solvents (COSMO-RS) was used as an initial screening tool to select the most suitable combination from a pool of 35 HBA and 64 HBD (2240 mixtures in total), thus reducing the number of experiments required. ES composed of terpenes, fatty acids, and some alcohols were found to be the most suitable solvents for phytosterols extraction. After validation using a standard mixture of sterols, the selected ES were successfully used to extract phytosterols from the macroalga Codium tomentosum. A maximum extraction yield of 3.16 ± 0.01 mg phytosterols/g dry macroalgae weight was obtained with ES menthol:octanoic acid (Men:AcC8), which was further selected to perform a sequential extraction procedure, allowing to obtain an enriched extract with a 4.4-fold increase in the phytosterol content after four extraction cycles. Overall, this study provides a promising, sustainable, and environmentally friendly approach to obtain bioactive phytosterols enriched extracts from macroalgae.