Ameliorative potential of phloridzin in type 2 diabetes-induced memory deficits in rats

Diabetes associated oxidative stress and impaired cholinergic neurotransmission causes cognitive deficits. Although phloridzin shows antioxidant- and insulin sensitizing-activities, its ameliorative potential in diabetes-induced memory dysfunction remains unexplored. In the present study, type 2 diabetes (T2D) was induced by streptozotocin (35 mg/kg, intraperitoneal) in rats on ad libitum high-fat diet. Diabetic animals were treated orally with phloridzin (10 and 20 mg/kg) for four weeks. Memory functions were evaluated by passive avoidance test (PAT) and novel object recognition (NOR) test. Brains of rats were subjected to biochemical analysis of glutathione (GSH), brain-derived neurotrophic factor (BDNF), malonaldehyde (MDA) and acetylcholinesterase (AChE). Role of cholinergic system in the effects of phloridzin was evaluated by scopolamine pre-treatment in behavioral studies. While diabetic rats showed a significant decrease in step through latency in PAT, and exploration time and discrimination index in NOR test; a substantial increase in all parameters was observed following phloridzin treatment. Phloridzin reversed abnormal levels of GSH, BDNF, MDA and AChE in the brain of diabetic animals. Moreover, in silico molecular docking study revealed that phloridzin acts as a potent agonist at M1 receptor as compared to acetylcholine. Viewed collectively, reversal of T2D-induced memory impairment by phloridzin might be attributed to upregulation of neurotrophic factors, reduced oxidative stress and increased cholinergic signaling in the brain. Therefore, phloridzin may be a promising molecule in the management of cognitive impairment comorbid with T2D.