Inhibitory effect of carvacrol on lipopolysaccharide-induced memory impairment in rats

Abstract

Neuroinflammation is an important process underlying a wide variety of neurodegenerative diseases. Carvacrol (CAR) is a phenolic monoterpene commonly used as a food additive due to its antibacterial properties, but it has also been shown to exhibit strong antioxidative, anti-inflammatory, and neuroprotective effects. Here, we sought to investigate the effects of CAR on inflammation in the hippocampus and prefrontal cortex, as well as the molecular mechanisms underlying these effects. In our study, lipopolysaccharide was injected into the lateral ventricle of rats to induce memory impairment and neuroinflammation. Daily administration of CAR (25, 50, and 100 mg/kg) for 21 days improved recognition, discrimination, and memory impairments relative to untreated controls. CAR administration significantly attenuated expression of several inflammatory factors in the brain, including interleukin-1β, tumor necrosis factor-α, and cyclooxygenase-2. In addition, CAR significantly increased expression of brain-derived neurotrophic factor (BDNF) mRNA, and decreased expression of Toll-like receptor 4 (TLR4) mRNA. Taken together, these results show that CAR can improve memory impairment caused by neuroinflammation. This cognitive enhancement is due to the anti-inflammatory effects of CAR medicated by its regulation of BDNF and TLR4. Thus, CAR has significant potential as an inhibitor of memory degeneration in neurodegenerative diseases.

Natural Dietary Supplement, Carvacrol, Alleviates LPS-Induced Oxidative Stress, Neurodegeneration, and Depressive-Like Behaviors via the Nrf2/HO-1 Pathway

“…31 Furthermore, carvacrol also attenuated behavioral deficits and memory impairment in a rat model possibly by enhancing brainderived neurotrophic factor (BDNF) associated with a decreased expression of TLR4 mRNA. 32 In another study, Melo et al demonstrated that carvacrol can mitigate depression-like symptoms by modulating dopamine levels. 33 Similarly, carvacrol attenuated ethanol-induced cognitive deficits by modulating MAPK cascade and mitochondrial pathways.…”

Protective Effects of Quercetin on Anxiety‐Like Symptoms and Neuroinflammation Induced by Lipopolysaccharide in Rats

“…Twenty-three days after LPS injection, IL-6, IL-1β, TNF-α, cyclooxygenase-2 (COX-2), and NF-κB levels were measured in the hippocampus as based on a previous study [22]. ree rats from each group were severely anesthetized with 1.2% isoflurane and were sacrificed.…”

“…Reaction. e expressions of inducible brain-derived neurotrophic factor (BDNF), TLR4, and nitric oxide synthase (iNOS) mRNA using RT-PCR were analyzed according to a previous study [22]. Total RNA was extracted from the hippocampus of each rat using TRIzol reagent.…”

Biopolymer nanoparticles: a strategy to enhance stability, bioavailability, and biological effects of phenolic compounds as functional ingredients

“…3 Different mechanisms have been described concerning the effects of phenolic compounds on healthfor example, reducing expression of inflammatory factors, and increasing brain-derived neurotrophic factor (BDNF) expression, which has an important role in growth, survival, and preservation of neurons. 18 Other action mechanisms include modulation of the gut microbiota, 19 decreased cancer cell proliferation, and increased apoptosis induction. 20 In addition to the pharmacological interest in these compounds, their biological activities have also been explored in other industry sectors (Fig.…”