New Insights into Potential Anti-Aging Effects of a Dietary Supplement from Chlorella Growth Factor and γ-PGA in Aged SAMP8 Mice

Aging is closely associated with oxidative stress, which contributes to functional decline and increased vulnerability to neurodegenerative diseases. Natural antioxidants, such as Chlorella Growth Factor (CGF) and γ-polyglutamic acid (γ-PGA), possess antioxidant and anti-aging properties; however, their combined effects remain unknown. This study investigated the potential synergistic effects of CGF and γ-PGA supplementation in senescence-accelerated mouse-prone 8 (SAMP8) mice, a model characterized by early cognitive decline, locomotor deficits, and elevated oxidative DNA damage. Three-month-old male SAMP8 mice (n = 40) were divided into four groups: control, CGF (49.2 mg/kg BW/day), γ-PGA (20.5 mg/kg BW/day), and combined CGF + γ-PGA (69.7 mg/kg BW/day), and were treated for 13 weeks. Behavioral and physiological assessments included locomotor activity, aging index, and cognitive function (passive and active avoidance tests). Biochemical analysis focused on brain 8-hydroxy-2'-deoxyguanosine (8-OHDG) as a biomarker of oxidative DNA damage. Supplementation with CGF and γ-PGA, particularly in combination, significantly improved locomotor activity, aging scores, and cognitive functions. Notably, the combined treatment yielded the greatest reduction in brain 8-OHDG levels. These findings indicate that CGF and γ-PGA, when administered together, exert enhanced protective effects against functional and molecular aging. In conclusion, long-term supplementation with CGF and γ-PGA protects against aging-related decline in SAMP8 mice. This study highlights the potential of CGF and γ-PGA as safe, natural candidates for the development of functional foods or nutraceuticals aimed at promoting healthy aging and reducing oxidative stress-associated disorders.