Investigating the protective and therapeutic potential of new generation antioxidant combinations in the brain: an experimental aging model

The increasing elderly population has brought healthy aging into focus. Aging is a multifactorial process characterized by the progressive decline of cellular and tissue functions, largely due to cumulative oxidative stress. Antioxidant-based strategies have therefore gained prominence as potential interventions. This study investigated the protective and therapeutic effects of Squalene (SQ) and Saponin (SP), individually and in combination, on aging-related biomarkers in brain tissue using a D-Galactose (D-Gal)-induced rat model. Forty-eight male Sprague-Dawley rats (200-250 g) were randomly divided into eight groups (n = 6). Aging was induced in four groups via intraperitoneal administration of D-Gal (300 mg/kg/day) for six weeks. One group received no antioxidants, while others were treated orally with SQ (2.66 mL/kg/day), SP (100 mg/kg/day), or their combination. Non-aging groups received the same antioxidant treatments without D-Gal. At the end of the intervention, brain tissues were collected for biochemical analysis. Spectrophotometric assessments included Malondialdehyde (MDA), Glutathione (GSH), Nitric oxide derivatives (NOx), Ascorbic acid (AA), and Protein carbonyls (PC). Forkhead Box O3A (FOXO3A), Nuclear factor erythroid 2-related factor 2 (NRF2), Sirtuin 1 (SIRT1), Paraoxonase 1 (PON1), and Klotho were quantified by ELISA. Combined SQ and SP treatment significantly decreased oxidative stress markers (MDA, NOx, PC) and increased antioxidant defenses (GSH, AA) as well as aging-related molecules (FOXO3A, NRF2, SIRT1, PON1, Klotho) (p < 0.05). Serum Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) levels were also reduced. These findings demonstrate, for the first time, that combined SQ and SP administration can mitigate aging-related oxidative stress and molecular alterations in brain tissue.