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.