The Effects of Flavonoids in Curcumin on Neurobehavioral Deficits in Insulin-resistant Rats

Abstract

Background: Diabetes mellitus is a risk factor for dementia, particularly Alzheimer's disease (AD). In a Wistar rat model, we studied Alzheimer-like symptoms using a high-fat diet (HFD) and streptozotocin (STZ) to replicate insulin resistance and the resulting neurobehavioral abnormalities. Curcumin, a flavonoid in turmeric, was studied for its potential therapeutic effects. Aim: This study sought to look at the exploratory, discriminatory, and spatial cognitive indices in rats. Materials and Methods: Thirty-six male Wistar rats were randomized into six groups and given the following treatments: olive oil only for control; curcumin only for the curcumin group; HFD and three doses STZ for the diabetic rats; HFD, three doses STZ, and concurrent treatment with curcumin for the protective group; pretreatment with curcumin, then HFD and three doses STZ for a preventive group; and HFD, three doses STZ, and curcumin for a therapeutic group. Subsequently, line and center line crossing frequency assessed rats' exploratory activities; rearing frequency data assessed novel environment behavior. The novel object recognition test and Morris water maze test assessed discrimination and spatial memory. Data were analyzed using one-way analysis of variance and Tukey's post hoc test. P < 0.05 was considered statistically significant. Results: Our findings revealed that insulin resistance prolonged escape latency of untreated diabetic rats; contrariwise, curcumin significantly reduced escape latency, increased difference score in novel object recognition paradigm, and increased explorative activities. Conclusion: Oral curcumin improves exploratory activity, discriminating memory, and spatial memory in male Wistar rats with AD-like neurobehavioral impairments. Patients with neurobehavioral abnormalities and comorbid insulin resistance may benefit from the flavonoids in curcumin.