Functional evaluation of spirulina extract: antioxidant properties and immune regulation in aged mice models

Background: Spirulina platensis is a cyanobacterium rich in protein, commonly regarded as a functional food due to its exceptional nutritional profile. Among its components, phycocyanin (a water-soluble pigment-protein complex) has gained attention for its strong antioxidant, anti-inflammatory, immunoregulatory, and liver-protective properties. Both oxidative stress and chronic inflammation are key drivers of the aging process and play major roles in the development of disease, namely metabolic syndromes and neurodegenerative disorders. Although spirulina has been widely studied for its health-promoting effects, its precise role in regulating systemic redox balance and modulating age-related immune responses remains insufficiently explored. This study aims to evaluate the antioxidant and anti-inflammatory activities of spirulina extract through in vitro assays and a murine aging model. Methods: Spirulina extract was prepared via enzymatic cell wall degradation followed by fermentation. Antioxidant activity was measured in vitro through four key assays: reducing power, total antioxidant capacity, DPPH radical scavenging, and superoxide anion scavenging. Additionally, young and middle-aged mice were orally administered spirulina extract at a dose of 7 mg per day for 28 days. Blood samples were collected to assess levels of GSSG and cytokines associated with Th1/Th2 immune regulation. Results: In vitro assays showed strong antioxidant activities, particularly DPPH radical scavenging (88.58 ± 3.68%). Spirulina extract significantly increased the GSH/GSSG ratio in middle-aged mice, indicating improved antioxidant status, while no changes were seen in young mice. Additionally, spirulina upregulated Th1 cytokines and downregulated Th2 cytokines in middle-aged mice, with significant reductions in IL-6 and -10. Spirulina extract demonstrated potent antioxidant and immunomodulatory effects, alleviating oxidative stress and correcting Th1/Th2 imbalance during aging. These results support its potential as a supplement for promoting healthy aging in the mouse model. Conclusion: Combining cell-based experiments with an aging mouse model, this research reveals new perspectives on spirulina’s impact on maintaining redox balance and modulating immune function. The results indicate that spirulina extract could be a beneficial supplement for addressing oxidative stress and immune aging during midlife. Further clinical studies are warranted to explore its potential as a functional food or nutraceutical aimed at reducing age-associated immune dysfunction and inflammation. Keywords: spirulina extract, antioxidant activity, cytokine, immune regulation.