Extraction, structural characterization, and antioxidant activity of polysaccharides from three microalgae

Area of Science:

• Biochemistry
• Marine Biology
• Biotechnology

Background:

• Microalgal polysaccharides are recognized for their potential in managing oxidative damage.
• Oxidative stress is implicated in various physiological and pathological conditions.

Purpose of the Study:

• To investigate the yield, structure, and antioxidant effects of polysaccharides from Golenkinia sp. (GPS), Chlorella sorokiniana (CPS), and Spirulina subsalsa (SPS).
• To elucidate the mechanisms by which these microalgal polysaccharides regulate oxidative stress, focusing on gene expression pathways.

Main Methods:

• Extraction of polysaccharides from three microalgal species using a standardized method.
• Characterization of polysaccharide structure, including molecular weight distribution and monosaccharide composition (primarily galactose).
• In vitro antioxidant activity assays and gene expression analysis (Nrf2-ARE pathway) to assess oxidative stress regulation.

Main Results:

• All extracted polysaccharides (GPS, CPS, SPS) were heteropolysaccharides with a high proportion of small molecular fractions, mainly galactose.
• SPS exhibited the highest yield and antioxidant activity, attributed to its higher proportion of small molecular fractions and galactose.
• GPS, CPS, and SPS demonstrated significant in vitro antioxidant capacity and effective regulation of cellular oxidative stress, with SPS showing slightly superior effects.

Conclusions:

• Microalgal polysaccharides, particularly SPS, possess significant antioxidant and oxidative stress-regulating properties.
• The Nrf2-ARE signaling pathway is a key mechanism through which these polysaccharides exert their effects on cellular oxidative stress.
• Findings support the potential of microalgal polysaccharides for applications in health products and further research.