Screening of effective solvents for obtaining antioxidant-rich seaweed extracts using principal component analysis

Supercritical fluid extraction (SFE) has garnered significant attention as a promising green technology for the isolation of bioactive constituents from natural sources. In the present study, an attempt has been made to investigate the comparative effectiveness of supercritical carbon dioxide and conventional food grade solvents such as water, 60%, 40%, and absolute ethanol, in extracting bioactive compounds from brown seaweeds (Sargassum wightii and Turbinaria conoides). The antioxidant potential of seaweed extracts prepared using conventional methodologies and SFE was evaluated in terms of total phenolics, antioxidant activity, etc. SFE was significantly (p < .05) effective in extracting seaweed constituents with highest total phenolic (27.56 mg gallic acid equivalents/g extract), flavonoid, and total antioxidant activity compared to conventional solvents. Observations on biplots of principal component analysis also concurred with the above research findings. The present findings highlighted that SFE can be recommended as an environmentally friendly technology for obtaining antioxidant-rich seaweed extracts with potential bioactivity.

Practical applications

Seaweeds, an important marine bioresource, serve as galore repository of biologically active phytochemicals such as fucoidan, phlorotannins, alginates, carotenoids, etc. Owing to their immense bioactivities, seaweeds/extracts and seaweed-based biomolecules are finding extensive applications in the areas of pharmaceuticals, functional food, biotechnology, etc. Conventional extraction which is the most commonly employed method for obtaining seaweed extracts has so many drawbacks. In this context, the use of a sustainable method such as SFE garners significant attention. The present work highlights the potential of SFE in obtaining extracts with high bioactivity from commercially important seaweeds, S. wightii, and T. conoides.