Prabhat Upadhyay,Ananya Sad
Abstract Epidemiological, clinical and experimental studies have shown a strong correlation between Diabetes mellitus (DM) and neurodegenerative disorders. Type II diabetes mellitus (T2DM) leads to elevated levels of plasma glucose and causes neurological complications including impairment of learning and memory processes. The pathogenesis mainly includes metabolic dysfunction due to brain insulin resistance, oxidative stress, inflammation and vascular complications. In this study we explored a new pharmacological intervention by investigating the neuroprotective effects of a standardized polyherbal formulation (PF) [(Bacopa monnieri (20 mg/kg), Hippophae rhamnoides (25 mg/kg), and Dioscorea bulbifera (15 mg/kg), p.o] on passive avoidance learning (PAL) and memory in normal and streptozotocin (STZ) induced diabetic rats. Treatment was started after the onset of hyperglycemia following STZ (60 mg/kg, i.p) injection. PAL and memory were assessed 30 days after treatment, followed by retention test 24 h after training. At the beginning and end, body weights and blood glucose measurements of the animals were done. The results showed STZ induced diabetic rats had severe impairments in acquisition and retrieval processes of PAL and memory. Treatment with the PF significantly improved cognitive deficits, increased body weight and lowered plasma glucose levels in the treated as compared to untreated diabetic rats. We hypothesize that acetyl choline enhancing, antioxidant, hypoglycemic and hypolipidemic properties of phytomolecule such as bacosides, quercetin, and diosgenin in the PF might be responsible for the nootropic effects of polyherbal formulation. Our study highlights the therapeutic potential of this polyherbal formulation for multi-targeted treatment of diabetes induced cognitive impairment.