Neuroprotective Effects of Myrtenal in an Experimental Model of Dementia Induced in Rats

Abstract

There is growing attention on natural substances capable of stimulating the cholinergic system and of exerting antioxidant effects, as potential therapeutic agents in Alzheimer’s disease (AD). The aim of the present study is to evaluate the expected neuroprotective mechanisms of myrtenal (M) in an experimental model of dementia in rats. Dementia was induced in male Wistar rats by scopolamine (Sc) administration (0.1 mg/kg for 8 days and 20.0 mg/kg on day 9). The animals were divided into 5 groups (1) Controls; (2) Sc; (3) Sc+Myrtenal (40 mg/kg); (4) Sc+Galantamine (1 mg/kg); (5) Sc + Lipoic acid (30 mg/kg). Changes in recognition memory and habituation were evaluated via the Novel Object Recognition and Open Field tests. Acetylcholinesterase (AChE) activity, ACh levels, and changes in oxidative status of the brain were measured biochemically. The histological changes in two brain regions—cortex and hippocampus, were evaluated qualitatively and quantitatively. Myrtenal improved recognition memory and habituation, exerted antioxidant effects and significantly increased ACh brain levels. Histologically, the neuroprotective capacity of myrtenal was also confirmed. For the first time, we have demonstrated the neuroprotective potential of myrtenal in an experimental model of dementia. Our study provides proof-of-concept for the testing of myrtenal, in association with standard of care treatments, in patients affected by cognitive decline.

New Myrtenal–Adamantane Conjugates Alleviate Alzheimer’s-Type Dementia in Rat Model

“…The ameliorative activity of M in conditions of scopolamine-induced AD-type dementia and the 6-OHDA-induced experimental model of Parkinson’s disease has been already demonstrated in our previous research [ 9 , 10 ]. Our results revealed its complex neuroprotective mechanisms of action, which are beneficial to the memory of rodents, neuromodulatory, and antioxidant, as supported by histopathological examinations.…”

“…As a muscarinic antagonist, Scop is widely used to initiate experimental dementia of the AD type [ 31 , 32 , 33 , 34 ]. Its intraperitoneal administration causes dysregulation of the brain’s cholinergic system with these consequences: increased AChE activity, oxidative stress, and decreased levels of ACh [ 9 , 35 , 36 ]. On the behavioral level, these biochemical changes are revealed as a pronounced cognitive deficit in the experimental animals.…”

“…M has demonstrated in vivo neuroprotective effects in scopolamine-induced dementia, manifested by memory improvement, cholinergic mediation stimulation, and specific antioxidant effects in rats’ brains. A histopathological investigation found a significantly increased number of vital neurons in the rat cerebral cortex [ 8 , 9 ]. In another experiment, we discovered that M had beneficial effects in the 6-hydroxydopamine (6-OHDA)-induced experimental model of Parkinson’s disease, with positive effects on memory and coordination, reduced oxidative stress, and increased dopamine content in the lesioned cerebral hemisphere in rats [ 10 ].…”

Mesenchymal stromal cell treatment attenuates repetitive mild traumatic brain injury-induced persistent cognitive deficits via suppressing ferroptosis

“…We performed the NOR test to evaluate the recognition memory of mice on days 28–30 post-rmTBI as reported [ 33 ]. The NOR tests are performed every morning in a quiet behavioral testing room (temperature 25 °C, humidity 56%).…”

Small Vessel Disease: Ancient Description, Novel Biomarkers

“…In the same way, rosmarinic acid induced a promotion of oxidative stress response and a reduced lipid-peroxidation [ 225 ], but also reduced the gene expression of inducible nitric oxide synthase [ 225 , 226 ], and promoted neuroprotection, reducing matrix metallopeptidase 2 (MMP2), and IL-1 beta [ 225 , 226 , 227 ]. Myrtenal has been recently employed as a multi-property substance (anti-inflammatory and anti-oxidant) [ 228 ] but results are only promising.…”