Cystoseira abies-marina is one of the most important brown algae species found in the Mediterranean Sea and Atlantic Ocean ecosystems and has been reported as a promising source of phenolic compounds, including phlorotannins. These compounds have recently raised attention due to their potential for the functional food and pharmaceutical industries due to the different bioactivities attributed to them. However, classical extracts of phlorotannins contained also other compounds like lipids or carbohydrates. In order to obtain more concentrated extracts, purification steps are needed and liquid/liquid procedures are frequently used to achieve this goal. Based on their behavior, new green processes can be proposed to eliminate/replace the use of traditional polluting and often toxic solvents, looking for higher efficiency and complying with the rules of green chemistry. In this regard, with the purpose to provide information on the chemical composition of the extract and drive the proposal in a properly way, pressurized liquid extraction (PLE) was employed to obtain extracts using mixtures of ethanol/water 95:5 and acetone/water 70:30 at 100 and 160ºC. The total phlorotannin content was quantified in the extract before and after the purification by DMBA colorimetric assay. Besides, a comprehensive two-dimensional liquid chromatography (LC × LC) method was applied to the richest samples to chemically characterize the native complex phlorotannins composition of C. abies-marina. Phlorotannins containing from 3 to 16 phloroglucinol units were identified. A study of solubility parameters of the most abundant phlorotannins in solvent mixtures and individual solvents ranging from non-polar to highly polar was carried out. Lastly, based on this information about the behavior of brown algae extracts, a new extraction strategy was designed to purify phlorotannins which involves a sequential procedure using supercritical fluid extraction (SFE) with pure carbon dioxide, SFE using ethanol as co-solvent and PLE using ethanol/water mixtures.

Resumen del trabajo presentado a la IV Iberoamerican Conference on Supercritical Fluids, celebrada en Viña del Mar (Chile) del 28 de marzo al 1 de abril de 2016.

Peer Reviewed