Objectives: Beta vulgaris, commonly known as beetroot, is a vegetable that contains red pigment and rich in betalains, phenolic acids, and flavonoids. This study was designed to assess the effect of beetroot supplemented diet (BRSD) on cognitive function and altered neurochemicals associated with Alzheimer's disease (AD) in the brain of rats treated with scopolamine (SCOP).
Methods: Rats were fed with BRSD (2 and 4%) for 14 days and administered with 2 mg/kg of SCOP intraperitoneally on the last day. Morris water Maze and Y-maze tests were performed to assess cognitive function. Purinergic enzymes [ectonucleotidase (NTPdase) and adenosine deaminase (ADA)], monoamine oxidase (MAO), and angiotensin-I converting enzyme (ACE) activities were determined in rat brain tissues. Furthermore, catalase activity, total thiol (T-SH) and non-protein thiol (NP-SH) levels were also assessed. Beetroot was characterized using liquid chromatography-mass spectrometry, and the structure-activity relationship between the constituents and target enzymes was assessed.
Results: BRSD improved cognitive function by increasing memory index in SCOP treated rats. An increase in NTPdase, ADA, MAO, and ACE activities were observed in the brain of rats treated with SCOP. However, the activities of these enzymes were significantly lower after treatment with BRSD. Treatment with BRSD triggered a significant increase in catalase activity, T-SH and NP-SH levels in SCOP-treated rats. Catechin, 6,7-benzocoumarin, gentisin, 5,7-dimethoxyflavone, and vulgaxanthin I was identified in beetroots.
Discussion: The result suggests that beetroot could prevent cognitive dysfunction in SCOP-treated rats, and enhance memory function, via modulation of purinergic enzymes, MAO and ACE activities, and neuronal antioxidant status.
Keywords: Alzheimer's disease; Beetroot; cognitive function; diets; neurodegeneration; oxidative stress; polyphenols; purinergic enzymes.