Polyherbal formulation mitigates age-associated cognitive deficits in rats.

BACKGROUND: Age-related cognitive decline is a common biological phenomenon that appears to be driven by accelerated oxidative stress pathways. As natural polyherbal phytoconstituents positively modulate such pathological changes, herbal formulations are gaining notable attention in the mitigation of age-associated cognitive impairments. OBJECTIVES: To study the effect of polyherbal extracts on cognitive functions in 52-54 weeks old rats compared to young adult rats. MATERIAL AND METHODS: The anxiety as well as learning and memory functions were assessed employing elevated plus maze, Morris water maze (MWM), and novel object recognition test (NORT). The levels of antioxidant enzymes, acetylcholinesterase (AChE), neurotransmitters, cytokines, and brain-derived neurotrophic factor (BDNF) were estimated in blood and/or brain samples using biochemical assays, LC-MS/MS, ELISA, and immunofluorescence methods. RESULTS: The peroral administration of polyherbal plant extracts for 12 weeks showed trends toward improvement of learning and memory functions in the MWM and/or NORT in 52-54 weeks old rats. The locomotor activity and anxiety-like behavior remained similar in young vs. aged rats. We noted lowered levels of antioxidant enzymes (superoxide dismutase, catalase, reduced glutathione, glutathione peroxidase, and homocysteine) and AChE in the frontal cortex of brain and/or blood samples of 52-54 weeks old rats. We also observed the negative impact of aging on the levels of neurotransmitters (dopamine, noradrenaline, and 5-HT), cytokines (TNF-α, IL-6, and CRP), BDNF, and NeuN expression in the hippocampus/frontal cortex in 52-54 weeks old rats vs. young rats. The altered levels of these antioxidant enzymes, AChE, neurotransmitters, cytokines, and other biogenic substances were reversed in polyherbal-recipient rats. CONCLUSIONS: Our results indicate that the memory-improving activity of polyherbal formulation may be attributed to antioxidant, anti-inflammatory, and neuroprotective properties. Thus, we suggest the utility of this Indian polyherbal formulation in delaying the onset or reducing age-associated cognitive impairments.