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نمایش مقاله

Title:

Study of the ameliorative effects of chamomile hydroalcoholic extract on memory impairment in the experimental model of Alzheimer's-diabetes induced by streptozotocin in rats

Subject:

Personalized Interventions and Diagnosis of Complex Neurological Disorders

Presenter Author:
Name:	Fatemeh Moradian

Author:
Name 1:	Fatemeh Moradian - Corresponding - Presenter
Affiliation 1:	Student Research Committee, School of Pharmacy Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Name 2:	Zahra babaei
Affiliation 2:	Master of Animal Physiology, Azad University, Marand, Iran

Name 3:	Seyyed Rezapour Rabi
Affiliation 3:	Assistant professor, Department of Biology, Faculty of Basic sciences, Azad University, Marand, Iran

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Abstract

Original Research

introduction :

Alzheimer's disease is a progressive neurodegenerative disorder characterized by a devastating decline in cognitive functions, particularly memory and learning. A key pathological feature involves the degeneration of cholinergic neurons in brain regions like the hippocampus and frontal cortex, coupled with the detrimental activity of the acetylcholinesterase (AChE) enzyme, which breaks down the essential neurotransmitter acetylcholine. Given the limitations and side effects of current pharmaceutical treatments, this study sought to investigate the potential neuroprotective properties of a hydroalcoholic extract of Matricaria chamomilla in a rat model of Alzheimer's disease. The model was established by inducing diabetes with streptozotocin (STZ), a compound known to cause central insulin resistance, hyperglycemia, and subsequent memory impairments that closely mirror the cognitive deficits observed in Alzheimer's disease.

Methods:

The experimental design utilized adult male Wistar rats, which were randomly allocated into several groups. The control group remained untreated, while the diabetic model groups received an intraperitoneal injection of STZ (40 mg/kg). Diabetic groups were then treated for 21 consecutive days with varying doses of the chamomile extract (100, 200, or 400 mg/kg, administered via gavage), the standard AChE inhibitor drug donepezil (4 mg/kg, IP), or a combination of the 200 mg/kg chamomile extract with donepezil. Additional vehicle control groups were also included to account for solvent effects. The critical assessment of cognitive function was performed using the passive avoidance learning test, a behavioral paradigm that effectively measures short-term (STL1) and long-term (STL2) memory retention based on the latency of the animals to enter a dark compartment where they had previously received a mild foot shock.

Results:

Induction of diabetes with STZ successfully resulted in significant memory impairment, as demonstrated by a significant reduction in latency time in the passive avoidance test compared to control groups. Treatment with chamomile extract showed a clear dose-dependent therapeutic effect. The lowest dose, 100 mg/kg, failed to produce any significant improvement in memory measures. However, the middle dose, 200 mg/kg, resulted in statistically significant improvements in both STL1 and STL2. Most strikingly, the highest dose of chamomile extract, 400 mg/kg, normalized memory performance, returning it to levels indistinguishable from healthy controls. As expected, the positive control drug donepezil also significantly reduced memory deficits. The most profound finding came from the combination treatment group, where co-administration of chamomile extract 200 mg/kg with donepezil had a powerful synergistic effect, producing the strongest and most complete recovery of memory function among all treatment groups.

Conclusion:

This research provides compelling experimental evidence that the hydroalcoholic extract of chamomile possesses substantial efficacy in mitigating learning and memory impairments in an STZ-induced rat model of Alzheimer's disease. The results underscore a definitive dose-response relationship, with the higher doses conferring significant neuroprotective benefits. Furthermore, the observed synergistic interaction between chamomile and the established drug donepezil suggests a promising potential for chamomile to be developed as a complementary or adjunctive therapy. This approach could potentially allow for lower dosages of conventional drugs, thereby minimizing their adverse side effects while enhancing therapeutic outcomes for cognitive disorders.

Keywords:

Alzheimer's Disease, Streptozotocin, Matricaria chamomilla, Donepezil, Passive Avoidance Learning, Memory