Blood Metabolomic Profiling of Systemic Responses to Dried Black Lychee in a Scopolamine-Induced Cognitive Impairment...

Cognitive impairment and memory decline represent major health concerns affecting older adults worldwide, and systemic metabolic dysfunction plays a critical role in their progression. Black lychee is produced from Litchi chinensis Sonn. through postharvest thermal processing. It contains polyphenolic compounds known for their neuroprotective properties. This study investigated the cognitive-enhancing effects of black lychee in a rat model of scopolamine-induced cognitive impairment. Male rats (n = 8 per group) received scopolamine (2 mg/kg, i.p.) alone or in combination with black lychee at 100, 200, or 400 mg/kg/day for 20 days. Untargeted blood metabolites and the phytochemical composition of black lychee were identified using ¹H-NMR spectroscopy. Cognitive performance was assessed using the passive avoidance test. Phytochemical analysis confirmed that black lychee is rich in polyphenols. All black lychee-treated groups showed a significant increase in step-through latency compared with the scopolamine group. Blood metabolomic analysis revealed alterations in 26 metabolic pathways associated with oxidative stress and energy metabolism. These findings suggest that polyphenols in black lychee attenuate scopolamine-induced cognitive impairment by reducing oxidative stress and restoring key metabolites involved in energy metabolism. These results support the potential of black lychee as a functional food for mitigating age-related cognitive decline.