2',6'-dihydroxy-4'-methoxy Dihydrochalcone Improves the Cognitive Impairment of Alzheimer's Disease: A Structure-activity Relationship Study.

Background: Chalcones and dihydrochalcones present potent inhibition of acetylcholinesterase, currently considered the most efficient approach for symptomatic treatment of Alzheimer's disease.

Objective: The present study aimed to explore the potential benefits of 2',6'-dihydroxy-4'-methoxy dihydrochalcone on the cognitive deficits of animals submitted to the streptozotocin-induced Alzheimer's model, as well as evaluating the possible mechanisms of action.

Methods: Learning and memory functions of different groups of animals were submitted to the streptozotocin-induced Alzheimer's model (STZ 2.5 mg/mL, i.c.v.) and subsequently treated with 2',6'-dihydroxy-4'-methoxy dihydrochalcone (DHMDC) administered at doses of 5, 15, and 30 mg/kg (p.o.), respectively. Rivastigmine (0,6 mg/kg, i.p.) and vehicle were evaluated in aversive memory test (inhibitory avoidance test) and spatial memory test (object recognition test). Molecular docking simulations were performed to predict the binding mode of DHMDC at the peripheral site of AChE, to analyze noncovalent enzyme-ligand interactions. DFT calculations were carried out to study well-known acetylcholinesterase inhibitors and DHMDC.

Results: DHMDC markedly increased the learning and memory of mice. STZ caused a significant decline of spatial and aversive memories in mice, attenuated by DHMDC (15 and 30 mg/kg). Furthermore, STZ conspicuously increased lipid peroxidation and compromised the antioxidant levels in mice brains. DHMDC pretreatment significantly increased GSH activity and other oxidative stress markers and decreased TBARS level in the brain of STZ administered mice. AChE activity was significantly decreased by DHMDC in the brain of mice.

Conclusion: The results together point out that DHMDC may be a useful drug in the management of dementia.