Multidimensional Neuroprotective Effects of Combined Ubisol-Q10 and Ashwagandha (Withania somnifera) in Male and Female 5XFAD Mice

Background/Objectives: Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterized by interconnected pathological processes including mitochondrial dysfunction, oxidative stress, impaired autophagic processes, neuroinflammation, neuronal degeneration, and progressive functional decline. Natural health products (NHPs), coenzyme-Q10 (CoQ10) and Ashwagandha (Withania somnifera) (ASH), have been previously reported to possess antioxidant, anti-inflammatory, mitochondrial-supportive, neuroprotective, and neurotrophic properties. This work investigates the neuroprotective effects of a bioavailability-enhanced formulation, Ubisol-Q10 (UQ), and ethanolic ASH extract, combined as a “Tonic,” across multiple domains of AD pathology. Methods: The effects of long-term administration were evaluated in male and female 5XFAD mice from 2.5 to 11 months of age. Longitudinal magnetic resonance imaging assessed hippocampal and white matter volumes, a frailty index assessed physiological resilience, Novel Object and Novel Location Recognition testing assessed spatial and non-spatial memory, while post-mortem Nissl, Golgi–Cox, and immunofluorescence evaluated cellular density, dendritic morphology, amyloid pathology, neuroinflammation, autophagy-associated signaling, and astrocytic activity. Results: Across these measures, Tonic treatment preserved brain volumes, reduced amyloid pathology and inflammation, and modulated autophagy-associated pathways. Treatment also preserved dendritic architecture, frailty progression, and novelty-recognition behavior. Females demonstrated particularly pronounced preservation of white matter structure and increased dendritic density, whereas males showed strong modulation of inflammatory and autophagy-associated markers. Astrocytic immunoreactivity also demonstrated sex- and region-specific patterns, suggesting that glial responses may contribute differently to structural preservation in males and females. Conclusions: Together, these findings support that UQ + ASH may provide diverse protection against AD neurodegeneration. The observed sex-specific responses emphasize the importance of incorporating sex into preclinical evaluation of novel interventions for neurodegenerative diseases.