Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Alzheimer's disease (AD) as the most common type of dementia, is affecting the life of many senior individuals around the world. Vinca herbacea Waldst. & Kit. (V. herbacea) as a middle east originated plant demonstrated antioxidant and antitumor effects. This plant traditionally used to treat diabetes and hypertension, but its mechanism remains unclear. AIM OF THE STUDY: In the present study, post-treatment effects of V. herbacea on learning and memory functions, antioxidant cellular defense and oxidative stress were investigated using the scopolamine rat model of AD. MATERIALS AND METHODS: Wistar male rats (170-190 g) were administered Scopolamine, an anti-muscarinic drug, (2 mg/kg) for 10 days followed by V. herbacea extract (200, 300 and 400 mg/kg) and/or donepezil (DON; 1 mg/kg, which were administered before behavioral studies for 10 consecutive days. All the rats were then subjected to Morris water maze (MWM) task. Biochemical parameters of oxidative stress were quantified using the whole brain. RESULTS: Our data showed significant decrease performance in target quadrant in water maze task following administration of scopolamine (SCOP). Also, V. herbacea and DON, did not induce any neurotoxicity and hepatotoxic effects at the highest utilized doses in healthy rats. Treatment with V. herbacea extract (200&400 mg/kg) and DON improved memory performance significantly in comparison with AD rats. In addition, V. herbacea extract in AD rats exhibited a decrease in malondialdehyde (MDA) and protein carbonyl (PCO) levels and an increase in total antioxidant capacity (FRAP) and glutathione (GSH) amounts in brain and liver. CONCLUSION: It seems that cholinergic deficits and oxidative stress are consistently associated with Alzheimer's disease (AD). The richness of V. herbacea in case of indole alkaloids and flavonoids confirms the potentials of this herb in management of oxidative stress, resorting synaptic acetylcholine level and improving cellular antioxidant resources.