Abstract
The prevalence of dementia following cerebral ischemia in metabolic syndrome (MetS) condition is increasing, and most of the cases are often severe. Unfortunately, no effective strategy for treating this condition is available. Based on the positive modulation effect of a polyphenol-rich substance on dementia and the improvement in bioavailability and stability of polyphenols induced by the phytosome technique together with the use of the synergistic concept, we hypothesized that a phytosome containing the combined extract of mulberry fruit and ginger (PMG) should mitigate dementia and memory impairment following ischemic stroke in MetS. MetS was induced in male Wistar rats weighing 180-200 g by exposure to a 16-week feeding period of high-carbohydrate high-fat (HCHF) diet. MetS rats were orally given PMG at doses of 50, 100, and 200 mg·kg(-1) BW 21 days before and 21 days after the occlusion of the right middle cerebral artery (Rt. MCAO). Then, their spatial memory was determined and the possible underlying mechanisms explored via the alterations of acetylcholinesterase (AChE), neuron density, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), interleukin-6 (IL-6), and signal transduction via extracellular signal-regulated kinase (ERK) pathway in both the cerebral cortex and the hippocampus. It was found that PMG significantly enhanced memory. It also decreased AChE, IL-6, and MDA but increased SOD, CAT, GSH-Px, neuron density, and phosphorylation of ERK. These data suggested the cognitive enhancing effect of PMG. The possible underlying mechanisms might occur partly via the improvement of cholinergic function via the ERK pathway together with the decrease in neurodegeneration induced by the reduction of oxidative stress and inflammation. However, a subchronic toxicity study is also required to assure the safety of PMG consumption before moving forward to a clinical trial study.